Merge branch 'master' into feat/issue-657-mcp-restart-path-inventory-guard

Merge pull request 'fix(reconciler): PR-scoped post-merge cleanup executor + expired reviewer-lease reclaim (Closes #855 )' (#866 ) from fix/issue-855-pr-scoped-merged-cleanup into master
Merge branch 'master' into fix/issue-855-pr-scoped-merged-cleanup
2026-07-24 04:10:08 -05:00 · 2026-07-24 03:24:53 -05:00 · 2026-07-24 03:15:43 -05:00 · 2026-07-24 03:04:24 -05:00 · 2026-07-24 02:42:52 -05:00 · 2026-07-24 02:26:02 -05:00
29 changed files with 10176 additions and 142 deletions
@@ -525,6 +525,90 @@ def assess_ownership_record_activity(record: dict[str, Any]) -> dict[str, Any]:
    }


+# Reviewer-lease reclaim is only reachable from a non-live (expired/stale) lease.
+_RECLAIMABLE_REVIEWER_STATUSES = _EXPIRED_STATUSES | _STALE_STATUSES
+
+
+def is_active_ownership_status(status: str | None) -> bool:
+    """True when *status* denotes live/active ownership of a branch (#855).
+
+    Used to decide whether a *competing* active claimant still uses a branch
+    when weighing an expired reviewer lease for reclaim. Expired, stale,
+    released, and terminal statuses are not active.
+    """
+    return _norm_str(status).lower() in _ACTIVE_OWNERSHIP_STATUSES
+
+
+def assess_expired_reviewer_lease_reclaim(
+    *,
+    role: str,
+    status: str,
+    pr_merged: bool | None,
+    owner_pid_alive: bool | None,
+    competing_active_claimant: bool | None,
+) -> dict[str, Any]:
+    """Decide, explicitly and fail-closed, whether an expired reviewer lease
+    may stop protecting an already-merged branch (#855 AC4).
+
+    An expired reviewer lease should not protect a merged branch forever once
+    its work is done and no live claimant remains. Reclaim is permitted only
+    when **every** condition below is provably satisfied; any unknown
+    (``None``) or contrary value keeps the lease protective:
+
+    - the lease is a ``reviewer`` lease (author/merger/controller/reconciler
+      leases are out of scope and always keep protecting);
+    - its status is expired or stale (never an active/live lease);
+    - the PR is proven merged (``pr_merged is True``);
+    - the lease owner process is proven dead (``owner_pid_alive is False``);
+    - no competing active claimant uses the branch
+      (``competing_active_claimant is False``).
+
+    Returns a decision dict with ``reclaim_allowed`` and, when refused, the
+    fail-closed ``reasons``. The reasons never contain secrets — only the
+    role, the status, and which condition was unproven.
+    """
+    reasons: list[str] = []
+    normalized_role = _norm_str(role).lower()
+    normalized_status = _norm_str(status).lower()
+
+    if normalized_role != "reviewer":
+        reasons.append(
+            f"lease role '{normalized_role or 'unknown'}' is not a reviewer "
+            "lease; expired-reviewer reclaim does not apply"
+        )
+    if normalized_status not in _RECLAIMABLE_REVIEWER_STATUSES:
+        reasons.append(
+            f"lease status '{normalized_status or 'unknown'}' is not expired "
+            "or stale; only a non-live reviewer lease may be reclaimed"
+        )
+    if pr_merged is not True:
+        reasons.append(
+            "PR merged state is not proven true; reclaim requires an "
+            "already-merged PR (fail closed)"
+        )
+    if owner_pid_alive is not False:
+        reasons.append(
+            "lease owner process liveness is not proven dead; a live owner "
+            "still protects the branch (fail closed)"
+        )
+    if competing_active_claimant is not False:
+        reasons.append(
+            "a competing active claimant may still use the branch; reclaim "
+            "requires no other active ownership (fail closed)"
+        )
+
+    allowed = not reasons
+    return {
+        "reclaim_allowed": allowed,
+        "role": normalized_role,
+        "status": normalized_status,
+        "decision": (
+            "reclaim_expired_reviewer_lease" if allowed else "keep_protecting"
+        ),
+        "reasons": [] if allowed else reasons,
+    }
+
+
 def assess_active_branch_ownership(
    *,
    remote: str,
@@ -46,6 +46,17 @@ _FIELD_RE = re.compile(
 )


+def is_known_cth_type(value: str | None) -> bool:
+    """True when *value* is a declared member of the :data:`CTH_TYPES` contract.
+
+    ``CTH_TYPES`` is the single authority for what a CTH type may be. The
+    heading a comment carries is free text, so a *read* path that turns a parsed
+    type into something durable — a serialized field, a routing decision — must
+    check membership here rather than trust the parse or keep a list of its own.
+    """
+    return (value or "").strip() in CTH_TYPES
+
+
 def format_cth_body(
    *,
    cth_type: str,
@@ -60,7 +71,7 @@ def format_cth_body(
 ) -> str:
    """Render a canonical CTH comment body."""
    normalized_type = (cth_type or "").strip()
-    if normalized_type not in CTH_TYPES:
+    if not is_known_cth_type(normalized_type):
        raise ValueError(
            f"unknown CTH type '{cth_type}'; expected one of {sorted(CTH_TYPES)}"
        )
@@ -101,6 +112,12 @@ def parse_cth_comment(body: str) -> dict[str, Any] | None:
        fields[key] = match.group(2).strip()
    return {
        "cth_type": cth_type,
+        # The heading capture is unconstrained free text, so the parse states
+        # whether it satisfies the CTH_TYPES contract instead of leaving every
+        # reader to decide (or forget). Parsing stays total — an unknown type is
+        # still parsed and reported, never raised on — but a reader that turns
+        # the type into a durable value can now tell the two apart.
+        "cth_type_known": is_known_cth_type(cth_type),
        "fields": fields,
        "raw_body": text,
    }
@@ -119,7 +136,7 @@ def assess_cth_comment(body: str) -> dict[str, Any]:
        }

    cth_type = parsed.get("cth_type") or ""
-    if cth_type not in CTH_TYPES:
+    if not is_known_cth_type(cth_type):
        reasons.append(
            f"unknown CTH type '{cth_type}'; expected one of {sorted(CTH_TYPES)}"
        )
@@ -0,0 +1,223 @@
+# ADR: MCP restart governance and authorization policy
+
+- **Status:** Accepted (policy effective immediately for LLM and operator sessions; enforcement tooling may lag)
+- **Date:** 2026-07-23
+- **Tracking issue:** [#656](https://gitea.prgs.cc/Scaled-Tech-Consulting/Gitea-Tools/issues/656)
+- **Policy version:** `restart-governance/v1`
+- **Related:**
+  - Umbrella: [#655](https://gitea.prgs.cc/Scaled-Tech-Consulting/Gitea-Tools/issues/655) — governed MCP restart coordination and zero-disruption recovery
+  - Vision: [#652](https://gitea.prgs.cc/Scaled-Tech-Consulting/Gitea-Tools/issues/652) — MCP Control Plane Web Console product vision (§A system health and process control)
+  - Roadmap: [#653](https://gitea.prgs.cc/Scaled-Tech-Consulting/Gitea-Tools/issues/653) — Control Plane Web Console phased delivery (Phase 2 restart controls)
+  - Contamination guard: [#630](https://gitea.prgs.cc/Scaled-Tech-Consulting/Gitea-Tools/issues/630) — blocks manual process-kill recovery
+  - Console restart UX: [#642](https://gitea.prgs.cc/Scaled-Tech-Consulting/Gitea-Tools/issues/642) — sanctioned restart and graceful reload
+  - Existing restart / reconnect paths to inventory: [#591](https://gitea.prgs.cc/Scaled-Tech-Consulting/Gitea-Tools/issues/591) — auto-restart on master advance (closed); [#584](https://gitea.prgs.cc/Scaled-Tech-Consulting/Gitea-Tools/issues/584) — host auto-reconnect on transport flap
+  - Stable-control runtime split: `docs/architecture/mcp-stable-control-runtime-policy-adr.md` (#615)
+  - Client-namespace health: `docs/mcp-namespace-health.md` (#543)
+  - Reconnect-only EOF recovery: `docs/mcp-namespace-eof-recovery.md`
+
+## 1. Context
+
+The Gitea MCP server is the **control plane** for real issue and PR mutations
+(create, comment, lock, review, merge, reconcile). The same process serves every
+role namespace (`gitea-author`, `gitea-reviewer`, `gitea-merger`,
+`gitea-reconciler`, `gitea-controller`) and holds the in-memory capability-gate
+code loaded at startup.
+
+Restarting that process is destructive to concurrent work:
+
+- It resets every session's identity, preflight, and capability-lease binding.
+- It can interrupt a mutation mid-critical-section (a lock acquire, a review
+  submit, a merge), leaving durable state half-written.
+- Relaunching from the wrong checkout or worktree silently changes which code
+  the control plane runs, defeating master-parity gates (#420 / #615).
+
+Today there is **no durable written policy** stating who may restart MCP, under
+what conditions, that restart is a last resort, and how controller approval,
+automated safety gates, and break-glass interact. Operators and LLM sessions
+therefore invent restart behavior ad hoc, which makes concurrent multi-role work
+unsafe. #630 and #642 need this policy as their backbone.
+
+This ADR defines that policy. It does **not** implement coordinator code or HA
+multi-instance restart (those are later children of #655).
+
+## 2. Decision
+
+### 2.1 v1 decision (recorded)
+
+**Restart authority in v1 is `controller approval + automated safety gates`.**
+
+A restart of the stable control runtime is authorized only when **both** hold:
+
+1. A **controller** role explicitly approves the restart, recording an audit
+   entry (who, why, scope, affected sessions), **and**
+2. The **automated safety gates** pass: a completed drain acknowledgement (no
+   affected session is mid-critical-section) or a declared break-glass incident
+   (§2.5).
+
+Quorum among multiple controllers is **not** required day-one. It is deferred
+unless a later investigation (tracked under #653) proves single-controller
+approval is insufficient. This ADR records the v1 decision so enforcement code
+(#630) has a fixed target; changing it requires a superseding ADR.
+
+### 2.2 Restart is a last resort — the recovery ladder
+
+Restart is the **last** rung. Before any restart, exhaust the narrower
+recoveries, in order:
+
+1. **Reconnect** the IDE/client MCP namespace (transport EOF, `client is
+   closing: EOF`, transient `#584` flap). No process change. See
+   `docs/mcp-namespace-eof-recovery.md`.
+2. **Refresh / rebind** the session workspace: re-run `gitea_whoami`,
+   `gitea_resolve_task_capability`, and pass an explicit validated
+   `worktree_path`. Fixes stale session context without touching the process.
+3. **Scoped restart** of a single misbehaving namespace/service (where the
+   deployment supports per-service restart) rather than the whole control plane.
+4. **Full restart** of the stable control runtime process — operator-owned,
+   controller-approved, drained.
+5. **Host / infrastructure restart** — the broadest action; same authorization
+   as a full restart plus infrastructure ownership.
+
+A session **must** try rungs 1–2 and record why they were insufficient before
+requesting a restart at rung 3 or above. Skipping straight to restart is a
+policy violation.
+
+### 2.3 Authorization matrix
+
+| Role | Reconnect (1) | Refresh/rebind (2) | Scoped restart (3) | Full restart (4) | Host restart (5) |
+|---|---|---|---|---|---|
+| **author** | self | self | request only | **forbidden** | forbidden |
+| **reviewer** | self | self | request only | **forbidden** | forbidden |
+| **merger** | self | self | request only | **forbidden** | forbidden |
+| **reconciler** | self | self | request only | **forbidden** | forbidden |
+| **controller** | self | self | **approve** (+gates) | **approve** (+gates) | request to operator |
+| **operator** | self | self | execute (controller-approved) | execute (controller-approved) | execute (controller-approved) |
+| **admin** | self | self | execute | execute | execute (break-glass) |
+
+Legend: *self* = may perform for its own client session; *request only* = may
+raise a restart request but not authorize or execute it; *approve* = may
+authorize under §2.1 gates; *execute* = may perform the process action after the
+authorization is recorded.
+
+Key invariants:
+
+- **No LLM worker role (author/reviewer/merger/reconciler) may perform or
+  authorize a full or host restart.** They may only reconnect/rebind their own
+  client and file a restart request.
+- **Controller approval authorizes; operator/admin executes.** The approving
+  controller and the executing operator may be the same human, but both the
+  approval and the execution are audited.
+- Privileged process actions (full restart, host restart) are reserved to
+  **operator/admin**, never to an automated worker.
+
+### 2.4 Approved conditions
+
+A restart at rung 3+ is approved only under one of these recorded conditions:
+
+- **No affected sessions:** the control plane has no live session that would be
+  interrupted (verified, not assumed).
+- **Full drain acknowledged:** every affected session has drained
+  (no open critical section — no held mutation lease mid-write) and the drain is
+  acknowledged in the audit record.
+- **Controller + gates:** controller approval plus passing automated safety
+  gates (§2.1), the standard v1 path.
+- **Quorum:** not required in v1; reserved for a future superseding ADR.
+- **Break-glass:** an incident-backed emergency exception (§2.5).
+
+Restart **never** bypasses mutation gates mid-critical-section. Drain before
+restart is mandatory except under break-glass with a declared incident.
+
+### 2.5 Break-glass
+
+Break-glass is a **separate, narrower** authorization path for emergencies where
+the normal drain-and-approve path cannot complete (e.g. the control plane is
+wedged and cannot drain).
+
+Break-glass conditions:
+
+- A declared incident record exists (id, timestamp, declarer) **before** the
+  action.
+- The action is taken by **operator or admin** authority only — never by an LLM
+  worker role, and never unilaterally by an operator with active peers when a
+  controller is reachable.
+- The scope is the minimum necessary rung of the ladder.
+- A **mandatory post-hoc audit** entry is filed: what was restarted, why the
+  normal path was impossible, which sessions were affected, and the incident id.
+
+Break-glass suspends the drain requirement, not the audit requirement.
+
+### 2.6 Explicit prohibitions
+
+- **A unilateral LLM or operator full restart while active peer sessions
+  exist is forbidden.** An LLM worker role must not kill, restart, or relaunch
+  the MCP process; a lone operator must not full-restart over live peer work
+  without controller approval or a break-glass incident.
+- Process-kill recovery is forbidden as a routine tool (#630). This ADR does not
+  introduce a kill path.
+- Ambiguous policy state **denies** restart (§4).
+
+## 3. Security requirements
+
+- Full restart and host restart are **privileged**; only operator/admin execute
+  them, only after a controller approval or break-glass incident is recorded.
+- Break-glass is a distinct authorization path with its own audit mandate; it is
+  never the default and never silent.
+- **Every approval and every restart action is audited** (who approved, who
+  executed, scope, affected sessions, condition, policy version). No restart is
+  authorized without a durable audit entry.
+
+## 4. Failure behavior
+
+**Ambiguous policy → deny restart.** If it cannot be established that a
+restart is authorized under §2 — unknown affected-session state, missing
+controller approval, absent break-glass incident, or an unclassifiable request —
+the safe action is to **refuse** the restart and stop with a recovery report,
+never to restart on assumption.
+
+## 5. Policy IDs (for enforcement code)
+
+Enforcement code — the restart coordinator (a later child of #655), the #630
+contamination guard, and the #642 console restart UX — binds to these stable
+policy identifiers rather than to prose:
+
+| Policy ID | Statement |
+|---|---|
+| `RG-01` | Restart is last resort; rungs 1–2 must be tried and recorded first (§2.2). |
+| `RG-02` | v1 authority = controller approval + automated safety gates (§2.1). |
+| `RG-03` | No LLM worker role performs or authorizes full/host restart (§2.3). |
+| `RG-04` | Full/host restart executed by operator/admin only, post approval (§2.3). |
+| `RG-05` | Drain before restart is mandatory except break-glass with incident (§2.4). |
+| `RG-06` | Break-glass requires a pre-declared incident and post-hoc audit (§2.5). |
+| `RG-07` | Unilateral LLM/operator full restart with active peers is forbidden (§2.6). |
+| `RG-08` | Ambiguous policy state denies restart (§4). |
+
+The `restart-governance/v1` **policy version** field is emitted on future
+restart audit events so approvals can be reconciled against the policy revision
+in force.
+
+## 6. Dogfooding
+
+Gitea-Tools governs its own MCP control plane by this policy. Author, reviewer,
+merger, and reconciler sessions operating on this repository use the recovery
+ladder (§2.2) — reconnect and rebind, never self-restart — and any real restart
+of the Gitea-Tools stable control runtime follows the controller-approval +
+drain path defined here.
+
+## 7. Acceptance and cross-links
+
+This ADR is the authoritative restart-governance policy. It **must** stay
+cross-linked from the safety model and the web-console deployment boundary:
+
+- `docs/safety-model.md` § Process restart governance references this ADR.
+- `docs/webui-deployment.md` references this ADR for restart/reload disposition.
+
+It is linked to its issue lineage — umbrella **#655**, vision **#652**, roadmap
+**#653**, contamination guard **#630**, and console restart UX **#642** — in
+§ Related above.
+
+## 8. Non-goals
+
+- Implementing the restart coordinator or approval state machine (#630, later
+  children of #655).
+- Implementing HA multi-instance restart or quorum machinery.
+- Introducing any process-kill or auto-restart tool; existing auto-restart
+  behavior must be inventoried before any new restart tool is enabled.
@@ -0,0 +1,90 @@
+# MCP restart / reload / kill path inventory (#657)
+
+Complete inventory of every code, script, and host path that can **restart,
+reload, reconnect, kill, or force-recreate** an MCP process in this project,
+with each path classified and linked to the guard that constrains it.
+
+This document is the human-readable companion to the machine-readable registry
+in [`mcp_restart_paths.py`](../mcp_restart_paths.py). The two are kept in
+lock-step by [`tests/test_mcp_restart_paths.py`](../tests/test_mcp_restart_paths.py):
+every `path_id` below must appear in this file, and the source guards are run
+against the live tree.
+
+Roadmap linkage: this inventory is the enumeration step of the restart
+governance work — parent **#655**, restart-governance ADR **#656**, vision
+**#652**, roadmap **#653**. Related detection/guard work: master-advance
+staleness **#591**/**#420**, side-effect-free resolver **#685**, transport flap
+**#584**, manual-kill contamination **#630**.
+
+## Classifications
+
+| Classification | Meaning |
+|---|---|
+| `sanctioned_narrow_recovery` | One-shot, safe-by-construction recovery that never targets the running daemon. |
+| `guarded_fail_closed` | Detects a restart-requiring condition, then fails mutations closed and emits reconnect guidance. Never self-restarts. |
+| `forbidden` | A workflow-safety violation; where an LLM tool could invoke it, it is marked contamination. |
+| `removed` | A previously-existing unguarded restart primitive that has been deleted; a regression guard keeps it absent. |
+| `host_residual` | Behavior owned by the host/IDE, outside this process's control. Documented, not code-guarded here. |
+
+## The rule
+
+**No component may perform an unguarded full restart of the MCP daemon.** The
+in-process daemon (`gitea_mcp_server.py`, `mcp_server.py`,
+`role_session_router.py`) must never replace or terminate its own process:
+replacing the process after the host has wired up the stdio pipes desyncs the
+JSON-RPC transport (observed with Antigravity/Cascade hosts). Recovery is owned
+by the host/operator via a client reconnect — the daemon only ever *detects*
+and *fails closed*.
+
+## Inventory
+
+| path_id | Classification | Mechanism | Guard | Refs |
+|---|---|---|---|---|
+| `cli_venv_bootstrap_execv` | sanctioned_narrow_recovery | CLI wrapper scripts re-exec into `venv/bin/python3` via `os.execv`, guarded by `sys.executable != venv_python`. | One-shot pre-import bootstrap; runs before any MCP transport exists and only when not already on the venv interpreter; idempotent guard prevents a re-exec loop. | #657 |
+| `daemon_self_replacement` | forbidden | The daemon replacing/terminating its own process (`os.execv`/`os.kill`/`os._exit`) to reload code. | Forbidden by design; enforced against the source tree by `assert_no_daemon_self_replacement()`. | #657, #584 |
+| `legacy_auto_restart_helper` | removed | A helper (`_trigger_mcp_auto_restart`) that actively restarted the server from the read-only resolver path. | Removed in #685; kept absent by `assert_auto_restart_helper_absent()`. | #685, #657 |
+| `config_touch_reload` | removed | Touching (utime) the MCP client config to make the host reload the server. | Removed from the resolver in #685: stale detection is report-only, never mutating config, spawning threads, or calling `os._exit`. | #685, #657 |
+| `master_advance_auto_restart` | guarded_fail_closed | On-disk master advancing past the running code. | `master_parity_gate` captures startup parity and blocks mutations while stale, emitting restart guidance; the process never self-restarts. | #420, #591, #657 |
+| `stale_runtime_resolver_reconnect` | guarded_fail_closed | The capability resolver detecting a stale serving process. | Report-only (#685): returns `restart_required`/`stop_required` and an exact reconnect action; no restart, thread, config touch, or `os._exit`. | #685, #657 |
+| `manual_daemon_kill` | forbidden | Shell kills of the daemon: `pkill -f mcp_server.py`, `killall`, broad `pkill -f python` sweeps, or `kill <pid>` of a daemon pid. | Forbidden (#630): `runtime_recovery_guard` classifies these as contamination and `gitea_record_daemon_process_kill_attempt` writes a durable marker that fails later mutations closed. Operator maintenance authorization is read only from the environment. | #630, #657 |
+| `conflict_marker_infra_stop` | guarded_fail_closed | The daemon entrypoint scans for unresolved merge-conflict markers at startup and stops (`sys.exit(1)`). | Fail-closed startup stop, not a restart: the process exits and waits for the operator to resolve conflicts and relaunch; never loops. | #657 |
+| `ide_client_reconnect` | host_residual | A manual `/mcp reconnect` (or equivalent host action) that recreates the MCP client connection. | Outside this process's control; the sanctioned recovery the gates point operators toward. No in-process code initiates it. | #584, #656, #657 |
+| `profile_switch_runtime` | sanctioned_narrow_recovery | Switching the active execution profile at runtime (dynamic-profile mode). | In-process and restart-free: `runtime_switching_supported` is true, so a switch rebinds capability without recreating the process. | #656, #657 |
+
+## Guards enforced in CI
+
+`tests/test_mcp_restart_paths.py` asserts, against the live source tree:
+
+1. **Registry well-formedness** — every path has a valid classification, a
+   non-empty guard description, references, and locations; ids are unique; all
+   five classifications are represented.
+2. **Unknown restart attempts fail closed** —
+   `assert_restart_attempt_registered()` raises `UnknownRestartPathError` for
+   any path id not in this inventory, so a novel/unnamed restart primitive
+   cannot slip through silently.
+3. **Daemon never self-replaces** — `assert_no_daemon_self_replacement()` scans
+   the daemon modules for `os.execv`/`os.kill`/`os._exit`/`os.abort` calls
+   (comment/docstring mentions are ignored) and finds none.
+4. **Legacy helper stays removed** — `assert_auto_restart_helper_absent()`
+   confirms `_trigger_mcp_auto_restart` has not returned.
+5. **pkill stays forbidden** — a daemon `pkill` command still classifies as
+   contamination via `runtime_recovery_guard`.
+
+## Residual host behaviors (outside process control)
+
+* `/mcp reconnect` in the IDE/host — the sanctioned recovery for stale-runtime,
+  transport-flap (#584), and worktree-binding conditions. The daemon can only
+  emit guidance toward it.
+* Host-level process management (the operator relaunching the daemon after a
+  fail-closed stop, or after resolving merge conflicts).
+
+These are documented rather than code-guarded because the process cannot
+observe or gate them from inside itself.
+
+## Rollout
+
+Per #657, guards are introduced flag-free as **regression assertions** (they
+codify invariants that already hold) before any hard runtime block is layered
+on. When the restart coordinator (#655/#656) lands, registered paths gain a
+coordinator token/capability check; unregistered attempts already fail closed
+today via `assert_restart_attempt_registered()`.
@@ -46,3 +46,17 @@ If shell helpers are unavailable and MCP commit cannot run, stop with a recovery
 report (restart session, clear hung terminals, use MCP-native commit). See
 [`llm-workflow-runbooks.md`](llm-workflow-runbooks.md) § MCP-native commit path
 (#260) and agent temp artifact cleanup (#261).
+
+## 7. Process restart governance
+
+Restarting the MCP control-plane process is destructive to concurrent multi-role
+work and is governed by a dedicated policy. Restart is a **last resort** behind
+narrower recoveries (reconnect, rebind), full/host restart is reserved to
+operator/admin under **controller approval + automated safety gates**, a
+unilateral LLM or operator full restart with active peers is **forbidden**, and
+ambiguous policy state **denies** restart. Break-glass is a separate,
+incident-backed path with a mandatory audit.
+
+See [`architecture/mcp-restart-governance.md`](architecture/mcp-restart-governance.md)
+(#656) for the authorization matrix, the recovery ladder, break-glass
+conditions, and the `RG-01`–`RG-08` policy IDs.
@@ -55,6 +55,15 @@ shipped to the browser.
 assumption paths, and the client-secret policy. Use it to verify an instance is
 configured for internal-only operation.

+## Process restart / reload disposition
+
+The console never exposes a restart or reload control; process restart of the
+MCP control-plane runtime is governed separately. Restart is a last resort behind
+reconnect/rebind, full restart is operator/admin-only under controller approval
+plus safety gates, and break-glass is an incident-backed path. See
+[`architecture/mcp-restart-governance.md`](architecture/mcp-restart-governance.md)
+(#656).
+
 ## Non-goals (MVP)

 - Full SSO or session login in the UI
@@ -317,6 +317,108 @@ health, workflow/schema SHA-256 hashes, and stale-runtime warnings when the
 checkout is behind merged safety-gate changes. Restart guidance links to #420;
 no tokens or MCP restart actions are exposed.

+## Workflow-event timeline (#637)
+
+`GET /api/v1/timeline` is a read-only, versioned aggregation of workflow
+events from every available source into one normalised, filterable stream. It
+is the model layer for the Phase 1 timeline console view (a later child issue
+of #631); this issue ships the schema, adapters, and read API only.
+
+### Schema (versioned)
+
+`webui/timeline.py` declares `TIMELINE_SCHEMA_VERSION` (currently `1`) and the
+frozen `WorkflowEvent` record. Every response carries `schema_version` so a
+consumer can branch on shape. One event:
+
+```json
+{
+  "source": "control_plane",
+  "event_type": "lease.renew",
+  "event_key": "cp:1421",
+  "timestamp": "2026-07-23T02:00:00Z",
+  "actor": null,
+  "role": null,
+  "issue_number": 637,
+  "pr_number": null,
+  "session_id": null,
+  "tool_name": null,
+  "decision": null,
+  "message": "lease renewed",
+  "correlation_id": "issue#637",
+  "evidence_refs": [],
+  "sensitive": true
+}
+```
+
+`event_key` is stable and unique per source (`cp:<event_id>`,
+`cth:<kind>:<number>:<comment_id>`), so pagination and dedup are deterministic.
+
+### Sources and field authority
+
+| Source | Adapter | Authority |
+|---|---|---|
+| Control-plane `events` ⋈ `work_items` | `adapt_cp_events` | `event_type`, `message`, `timestamp`, issue/PR scope come from the CP database, read through a `mode=ro` URI (never creates the DB or runs migrations) |
+| Gitea Canonical Thread Handoff comments | `adapt_cth_comments` | `actor`, `role` (next owner), `decision`, `evidence_refs`, `timestamp` come from the parsed CTH comment body (`canonical_thread_handoff`) |
+
+Handoff comments are thread-scoped: they are only read when the request filters
+by a single `issue` or `pr`. Otherwise the handoff source reports `not run`
+with a reason — it is never rendered as empty-and-healthy. Each source degrades
+independently: an unavailable control-plane DB or a failed comment fetch is a
+`sources[]` entry with `ok:false` and a `reason`, never a dropped timeline.
+
+### Query parameters
+
+`issue`, `pr`, `session` (conjunctive filters); `limit` (default 50, max 500)
+and `offset` for pagination; `remote`, `org`, `repo` to override the default
+registry-project scope. Events sort ascending by
+`(timestamp, source_rank, event_key)`; missing timestamps sort last.
+
+### Filter authority, and refusing what cannot be answered
+
+A filter dimension is only meaningful for a source whose records carry it.
+Each source declares its own support in `_SOURCE_FILTER_SUPPORT` and reports it
+per response as `supported_filters` / `unsupported_filters`:
+
+| Source | issue | pr | session |
+|---|---|---|---|
+| `control_plane` | yes | yes | **no** — the `events` table is `(event_id, work_item_id, event_type, message, created_at)` and records no session |
+| `gitea_handoff` | yes | yes | yes — a CTH comment declares its own `Session:` field |
+
+`session_id` is read only from that declared CTH field. It is never inferred
+from a work item, an actor, or message text, and a value that is
+redaction-altering or bare-secret-shaped is dropped rather than emitted.
+
+When **no source that ran** can carry a requested dimension, the request is
+refused rather than answered: the response is `422` with `ok:false` and a
+structured `error` naming `unsupported_filters` and the per-source reason. A
+`200` with zero events would tell an operator that no such activity exists,
+which is a stronger — and false — claim than "this cannot be answered here".
+A source that *can* answer the dimension and simply matched nothing still
+returns `200` with `ok:true` and an empty page.
+
+### Redaction
+
+Every free-text field (event messages, decision/proof text, roles, actors) is
+passed through the console redaction policy (`webui.console_redaction`, backed
+by `gitea_audit.redact`) before it leaves the module, failing closed to the
+placeholder. No unredacted tool arguments or secrets are ever emitted, and a
+generation error never drops raw data to a caller or a log.
+
+Redaction also runs *before* any structured value is derived from free text.
+`evidence_refs` are extracted from already-redacted proof/decision text, and a
+commit reference is recognised only where the text declares one (`commit`,
+`head`, `base`, `sha`, …). An undeclared 40-character hex run has the exact
+shape of a Gitea access token, so it is never lifted out of prose into a
+structured field. Every reference is then independently revalidated against an
+allowed shape and a second redaction pass immediately before serialization;
+anything unproven is dropped and the event is flagged `sensitive`.
+
+### Tests
+
+```bash
+pytest tests/test_webui_timeline.py -q
+```
+
 ## Tests

 ```bash
@@ -16,11 +16,16 @@ ISSUE_LOCK_FILE = os.environ.get("GITEA_ISSUE_LOCK_FILE", "/tmp/gitea_issue_lock
 SOURCE_LOCK_ISSUE = "gitea_lock_issue"
 SOURCE_LOCK_ADOPTION = "gitea_lock_issue_adoption"
 SOURCE_OPERATOR_OVERRIDE = "operator_override"
+# #864: dirty-preserving same-claimant author-session rebind (dead owner PID).
+SOURCE_DIRTY_SAME_CLAIMANT_REBIND = (
+    "gitea_rebind_dirty_same_claimant_author_session"
+)

 SANCTIONED_LOCK_SOURCES = frozenset({
    SOURCE_LOCK_ISSUE,
    SOURCE_LOCK_ADOPTION,
    SOURCE_OPERATOR_OVERRIDE,
+    SOURCE_DIRTY_SAME_CLAIMANT_REBIND,
 })

 _OPERATOR_OVERRIDE_ENV = "GITEA_ISSUE_LOCK_OPERATOR_OVERRIDE"
@@ -85,6 +85,12 @@ HEAD_RELATION_STRICT_DESCENDANT = "strict_descendant"
 # #772: an unpublished claim has no recorded head to compare against at all, so
 # its head is measured against the base the branch was cut from instead.
 HEAD_RELATION_DESCENDS_FROM_BASE = "descends_from_recorded_base"
+# #871: the remote/PR head advanced *past* the recorded head via a sanctioned
+# merge-based branch synchronization (``gitea_update_pr_branch_by_merge``) while
+# the local worktree stayed at the recorded head. This is the inverse of the
+# #768 descendant relation — here the *remote* strictly descends the local head,
+# and only because a base was merged into the branch, proven server-side.
+HEAD_RELATION_REMOTE_MERGE_SYNCED = "remote_merge_synced"

 # Which body of evidence a recovery was decided on (#772 AC10). These are not
 # interchangeable: a published claim proves ownership against a remote/PR head,
@@ -266,6 +272,70 @@ def _assess_base_descendancy(
    ]


+def _assess_remote_merge_synced(
+    sync_provenance: Mapping[str, Any] | None,
+    *,
+    recorded_head: str,
+    remote_head: str,
+) -> tuple[bool, list[str]]:
+    """Did ``remote_head`` advance past ``recorded_head`` via a sanctioned
+    merge-based branch sync (#871)?
+
+    ``sync_provenance`` is the server-side git observation from
+    ``issue_lock_worktree.read_merge_sync_provenance``. Its own
+    ``prior_head_sha`` / ``synced_head_sha`` are re-checked against the heads
+    this assessment is actually reasoning about, so an observation taken for some
+    other pair of commits — stale, mismatched, or hand-built — can never
+    authorize recovery. This is the inverse of ``_assess_strict_descendant``: the
+    recorded head is the ancestor and the *remote* head is the descendant, and it
+    is accepted only because the remote head is a base-into-branch merge that
+    preserved the branch mainline back to the recorded head.
+
+    Returns ``(proven, notes)``. Notes name the exact missing element so a
+    refused caller sees why, never a bare "unproven".
+    """
+    if not isinstance(sync_provenance, Mapping):
+        return False, [
+            "no server-derived merge-sync provenance observation was available; a "
+            "remote head ahead of the recorded head cannot be accepted"
+        ]
+
+    probe_prior = _text(sync_provenance.get("prior_head_sha"))
+    probe_synced = _text(sync_provenance.get("synced_head_sha"))
+    if probe_prior != recorded_head or probe_synced != remote_head:
+        return False, [
+            f"merge-sync observation covers {probe_prior or 'unknown'} -> "
+            f"{probe_synced or 'unknown'}, not the heads under assessment "
+            f"({recorded_head} -> {remote_head})"
+        ]
+    if not sync_provenance.get("probe_ok"):
+        return False, (
+            list(sync_provenance.get("reasons") or [])
+            or ["merge-sync provenance probe did not complete; provenance unproven"]
+        )
+    if not sync_provenance.get("prior_is_ancestor"):
+        return False, [
+            f"recorded head {recorded_head} is not an ancestor of remote head "
+            f"{remote_head}; a rewritten or force-moved head cannot be recovered"
+        ]
+    if not sync_provenance.get("is_merge_sync"):
+        return False, (
+            list(sync_provenance.get("reasons") or [])
+            or [
+                f"remote head {remote_head} is not a sanctioned merge-based sync "
+                f"of the base into the branch above {recorded_head}"
+            ]
+        )
+
+    proof = _text(sync_provenance.get("proof")) or (
+        f"{remote_head} merged the base into the branch above {recorded_head}"
+    )
+    return True, [
+        f"remote head {remote_head} advanced past recorded head {recorded_head} "
+        f"via a sanctioned merge-based branch sync ({proof})"
+    ]
+
+
 def assess_dead_session_lock_recovery(
    existing_lock: Mapping[str, Any] | None,
    *,
@@ -290,6 +360,7 @@ def assess_dead_session_lock_recovery(
    remote_branch_exists: bool | None = None,
    recorded_base_sha: str | None = None,
    base_ancestry: Mapping[str, Any] | None = None,
+    sync_provenance: Mapping[str, Any] | None = None,
 ) -> dict[str, Any]:
    """Decide whether a dead-session author lock may be natively recovered.

@@ -469,19 +540,39 @@ def assess_dead_session_lock_recovery(
                    head_relation = HEAD_RELATION_STRICT_DESCENDANT
                    ancestry_proof = notes[0] if notes else None
                else:
-                    reasons.append(
-                        f"local head {local_head} does not match remote branch head "
-                        f"{remote_head}"
+                    # #871: the reverse relation — the remote head advanced past
+                    # the recorded/local head via a sanctioned merge-based branch
+                    # sync while the local worktree stayed put. Accepted only on
+                    # server-proven merge-sync provenance, never a caller claim.
+                    synced, sync_notes = _assess_remote_merge_synced(
+                        sync_provenance,
+                        recorded_head=local_head,
+                        remote_head=remote_head,
                    )
-                    reasons.extend(notes)
+                    if synced:
+                        head_relation = HEAD_RELATION_REMOTE_MERGE_SYNCED
+                        ancestry_proof = sync_notes[0] if sync_notes else None
+                    else:
+                        reasons.append(
+                            f"local head {local_head} does not match remote branch "
+                            f"head {remote_head}"
+                        )
+                        reasons.extend(notes)
+                        reasons.extend(sync_notes)
    evidence["recorded_base"] = recorded_base or None
    evidence["local_head"] = local_head or None
    evidence["remote_head"] = remote_head or None
    # ``recorded_head`` is the head recovery is being measured against;
    # ``accepted_head`` is the head this recovery actually adopts. They differ
    # only in the descendant case, and downstream gates need both (#768 AC2/AC7).
+    # #871: in the merge-sync case the branch/PR already carries the synced
+    # remote head, so that is the head recovery adopts; the local worktree stays
+    # at the ancestor recorded head.
    evidence["recorded_head"] = remote_head or None
-    evidence["accepted_head"] = local_head or None
+    if head_relation == HEAD_RELATION_REMOTE_MERGE_SYNCED:
+        evidence["accepted_head"] = remote_head or None
+    else:
+        evidence["accepted_head"] = local_head or None
    evidence["head_relation"] = head_relation
    evidence["ancestry_proof"] = ancestry_proof

@@ -493,12 +584,17 @@ def assess_dead_session_lock_recovery(
        # contradictory; re-stating it as a head mismatch would only obscure why.
        if not unpublished and local_head and pr_head != local_head:
            # A descendant recovery has not been published yet, so the open PR
-            # legitimately still points at the recorded head. Any other
-            # disagreement is a real mismatch.
+            # legitimately still points at the recorded head. A merge-sync
+            # recovery's PR legitimately sits at the advanced remote head. Any
+            # other disagreement is a real mismatch.
            if not (
                head_relation == HEAD_RELATION_STRICT_DESCENDANT
                and remote_head
                and pr_head == remote_head
+            ) and not (
+                head_relation == HEAD_RELATION_REMOTE_MERGE_SYNCED
+                and remote_head
+                and pr_head == remote_head
            ):
                reasons.append(
                    f"open PR #{pr_number} head {pr_head} does not match local head "
@@ -619,7 +715,11 @@ def assess_dead_session_lock_recovery(
        )
    if (
        head_relation
-        in (HEAD_RELATION_STRICT_DESCENDANT, HEAD_RELATION_DESCENDS_FROM_BASE)
+        in (
+            HEAD_RELATION_STRICT_DESCENDANT,
+            HEAD_RELATION_DESCENDS_FROM_BASE,
+            HEAD_RELATION_REMOTE_MERGE_SYNCED,
+        )
        and ancestry_proof
    ):
        proof.append(ancestry_proof)
@@ -697,6 +797,16 @@ def owning_pr_recovery_evidence(
            return None
        if accepted_head != local_head:
            return None
+    elif relation == HEAD_RELATION_REMOTE_MERGE_SYNCED:
+        # #871: the PR already sits at the advanced remote head; the local
+        # worktree is the ancestor the merge preserved. The head the open PR
+        # shows and the head recovery adopts are both the synced remote head.
+        if not remote_head or pr_head != remote_head:
+            return None
+        if accepted_head != remote_head:
+            return None
+        if not local_head or local_head == remote_head:
+            return None
    else:
        return None
    try:
@@ -765,6 +875,18 @@ def recovered_owning_pr_from_lock(
            return None
        if not accepted_head or accepted_head == recorded_head:
            return None
+    elif relation == HEAD_RELATION_REMOTE_MERGE_SYNCED:
+        # #871: PR sits at the advanced remote head, which is both the recorded
+        # measured-against head and the adopted head; the local worktree is the
+        # ancestor the merge preserved.
+        remote_head = _text(record.get("remote_head"))
+        local_head = _text(record.get("local_head"))
+        if not remote_head or pr_head != remote_head:
+            return None
+        if accepted_head and accepted_head != remote_head:
+            return None
+        if not local_head or local_head == remote_head:
+            return None
    else:
        return None
    try:
@@ -737,4 +737,308 @@ def format_lock_proof(
        parts.append("lock released")
    elif released is False:
        parts.append("lock retained")
-    return "; ".join(parts)
+    return "; ".join(parts)
+
+
+# ── #871: durable linked-issue lock head refresh after branch synchronization ──
+_FULL_SHA_RE = re.compile(r"^[0-9a-f]{40}$", re.IGNORECASE)
+
+# Provenance recorded on the lock when the head is refreshed by a sanctioned
+# merge-based branch synchronization (``gitea_update_pr_branch_by_merge``).
+LOCK_HEAD_REFRESH_PROVENANCE_MERGE_SYNC = "gitea_update_pr_branch_by_merge"
+
+
+def _norm_sha(value: Any) -> str | None:
+    text = str(value or "").strip().lower()
+    return text if _FULL_SHA_RE.match(text) else None
+
+
+def _lock_claimant_view(lock: dict[str, Any] | None) -> dict[str, Any]:
+    if not isinstance(lock, dict):
+        return {}
+    claimant = lock.get("claimant")
+    if not isinstance(claimant, dict):
+        lease = lock.get("work_lease")
+        claimant = lease.get("claimant") if isinstance(lease, dict) else None
+    return dict(claimant) if isinstance(claimant, dict) else {}
+
+
+def assess_durable_lock_head_refresh(
+    existing_lock: dict[str, Any] | None,
+    *,
+    remote: str,
+    org: str,
+    repo: str,
+    issue_number: int,
+    branch_name: str,
+    worktree_path: str,
+    pr_number: int | None,
+    identity: str | None,
+    profile: str | None,
+    current_pid: int | None,
+    expected_old_head: str | None,
+    new_head: str | None,
+    base_head: str | None = None,
+) -> dict[str, Any]:
+    """Fail-closed assessment for refreshing a durable lock's recorded head (#871).
+
+    A successful ``gitea_update_pr_branch_by_merge`` advances the *remote* PR head
+    but must also advance the durable linked-issue lock so a later dead-session
+    recovery can prove ownership. This decides whether that refresh is permitted;
+    it mutates nothing.
+
+    Every element of durable ownership is re-verified against the persisted lock —
+    repository, issue, branch, worktree, claimant identity/profile, and the live
+    owning session — and the recorded head is compare-and-swapped: the lock's
+    currently recorded synced head (if any) must equal ``expected_old_head``, so a
+    lock whose head or provenance changed concurrently is never overwritten.
+    """
+    reasons: list[str] = []
+    old = _norm_sha(expected_old_head)
+    new = _norm_sha(new_head)
+    evidence: dict[str, Any] = {
+        "issue_number": issue_number,
+        "branch_name": branch_name,
+        "worktree_path": worktree_path,
+        "pr_number": pr_number,
+        "expected_old_head": old,
+        "new_head": new,
+        "base_head": _norm_sha(base_head),
+    }
+
+    if not isinstance(existing_lock, dict) or not existing_lock:
+        reasons.append("no durable lock exists for this issue; nothing to refresh")
+        return {"allowed": False, "reasons": reasons, "evidence": evidence,
+                "expected_generation": 0}
+
+    lock = dict(existing_lock)
+    evidence["current_generation"] = lock_generation(lock)
+
+    if lock.get("issue_number") != issue_number:
+        reasons.append(
+            f"durable lock targets issue #{lock.get('issue_number')}, not "
+            f"#{issue_number}; refusing head refresh"
+        )
+
+    for field, expected in (("remote", remote), ("org", org), ("repo", repo)):
+        actual = str(lock.get(field) or "").strip()
+        if actual != str(expected or "").strip():
+            reasons.append(
+                f"lock {field} '{actual}' does not match requested "
+                f"'{str(expected or '').strip()}'"
+            )
+
+    locked_branch = str(lock.get("branch_name") or "").strip()
+    if locked_branch != str(branch_name or "").strip():
+        reasons.append(
+            f"lock branch '{locked_branch}' does not match requested "
+            f"'{str(branch_name or '').strip()}'"
+        )
+
+    locked_worktree = str(lock.get("worktree_path") or "").strip()
+    try:
+        same_wt = bool(locked_worktree) and bool(worktree_path) and (
+            os.path.realpath(locked_worktree) == os.path.realpath(worktree_path)
+        )
+    except OSError:
+        same_wt = locked_worktree == (worktree_path or "")
+    if not same_wt:
+        reasons.append(
+            f"lock worktree '{locked_worktree}' does not match declared "
+            f"'{str(worktree_path or '').strip()}'"
+        )
+
+    claimant = _lock_claimant_view(lock)
+    locked_identity = str(claimant.get("username") or "").strip()
+    locked_profile = str(claimant.get("profile") or "").strip()
+    if not locked_identity or not locked_profile:
+        reasons.append(
+            "durable lock does not record a claimant identity/profile; "
+            "ownership could not be proven for head refresh"
+        )
+    if not str(identity or "").strip() or not str(profile or "").strip():
+        reasons.append(
+            "active session identity/profile is unknown; ownership could not be "
+            "proven for head refresh"
+        )
+    if locked_identity and str(identity or "").strip() and locked_identity != str(identity).strip():
+        reasons.append(
+            f"lock claimant '{locked_identity}' does not match active identity "
+            f"'{str(identity).strip()}'"
+        )
+    if locked_profile and str(profile or "").strip() and locked_profile != str(profile).strip():
+        reasons.append(
+            f"lock profile '{locked_profile}' does not match active profile "
+            f"'{str(profile).strip()}'"
+        )
+
+    # The refresh is written by the LIVE owning author session. A refresh is not
+    # a recovery: the current process must be the recorded owner.
+    recorded_pid = lock.get("session_pid")
+    if recorded_pid is None:
+        recorded_pid = lock.get("pid")
+    evidence["recorded_pid"] = recorded_pid
+    evidence["current_pid"] = current_pid
+    if current_pid is None:
+        reasons.append("current session pid is unknown; cannot prove live ownership")
+    else:
+        try:
+            if recorded_pid is None or int(recorded_pid) != int(current_pid):
+                reasons.append(
+                    f"durable lock is owned by pid {recorded_pid}, not the current "
+                    f"session pid {current_pid}; head refresh requires the live owner"
+                )
+        except (TypeError, ValueError):
+            reasons.append(
+                "durable lock owner pid is malformed; cannot prove live ownership"
+            )
+
+    if not old:
+        reasons.append("expected_old_head is not a full 40-char hex SHA (fail closed)")
+    if not new:
+        reasons.append("new_head is not a full 40-char hex SHA (fail closed)")
+    if old and new and old == new:
+        reasons.append(
+            "new head equals the expected old head; a sync must advance the head"
+        )
+
+    # Compare-and-swap on the recorded head: if the lock already records a synced
+    # head it must be exactly the expected old head, else another sync moved it.
+    recorded_synced = _norm_sha(lock.get("synced_pr_head"))
+    evidence["recorded_synced_pr_head"] = recorded_synced
+    if recorded_synced is not None and old is not None and recorded_synced != old:
+        reasons.append(
+            f"durable lock already records synced head {recorded_synced}, not the "
+            f"expected old head {old}; a concurrent sync changed it (CAS fail closed)"
+        )
+
+    if reasons:
+        return {"allowed": False, "reasons": reasons, "evidence": evidence,
+                "expected_generation": lock_generation(lock)}
+
+    return {
+        "allowed": True,
+        "reasons": [
+            f"durable lock for issue #{issue_number} branch '{locked_branch}' is "
+            f"owned by the live session; refresh recorded head {old} -> {new}"
+        ],
+        "evidence": evidence,
+        "expected_generation": lock_generation(lock),
+    }
+
+
+def apply_durable_lock_head_refresh(
+    *,
+    remote: str,
+    org: str,
+    repo: str,
+    issue_number: int,
+    branch_name: str,
+    worktree_path: str,
+    pr_number: int | None,
+    identity: str | None,
+    profile: str | None,
+    current_pid: int | None,
+    expected_old_head: str | None,
+    new_head: str | None,
+    synced_at: str,
+    base_head: str | None = None,
+    provenance: str = LOCK_HEAD_REFRESH_PROVENANCE_MERGE_SYNC,
+    lock_dir: str | None = None,
+) -> dict[str, Any]:
+    """CAS-refresh the durable lock's recorded head after a branch sync (#871).
+
+    Reads the durable lock from disk, re-asserts ownership via
+    ``assess_durable_lock_head_refresh``, and — only when permitted — writes the
+    new synced head through ``bind_session_lock`` with a generation compare-and-
+    swap. Then re-reads the lock and proves it records the complete new head
+    (read-after-write). Any failure at any step returns ``refreshed=False`` with
+    reasons; the caller must treat that as a partial lifecycle failure and never
+    report a fully successful synchronization.
+    """
+    existing = load_issue_lock(
+        remote=remote, org=org, repo=repo, issue_number=issue_number, lock_dir=lock_dir
+    )
+    assessment = assess_durable_lock_head_refresh(
+        existing,
+        remote=remote,
+        org=org,
+        repo=repo,
+        issue_number=issue_number,
+        branch_name=branch_name,
+        worktree_path=worktree_path,
+        pr_number=pr_number,
+        identity=identity,
+        profile=profile,
+        current_pid=current_pid,
+        expected_old_head=expected_old_head,
+        new_head=new_head,
+        base_head=base_head,
+    )
+    result: dict[str, Any] = {
+        "refreshed": False,
+        "read_after_write_ok": False,
+        "prior_head": _norm_sha(expected_old_head),
+        "new_head": _norm_sha(new_head),
+        "reasons": list(assessment.get("reasons") or []),
+        "evidence": assessment.get("evidence"),
+    }
+    if not assessment.get("allowed"):
+        return result
+
+    new = _norm_sha(new_head)
+    old = _norm_sha(expected_old_head)
+    record = dict(existing or {})
+    sync_block = {
+        "last_synced_pr_head": new,
+        "prior_pr_head": old,
+        "base_head": _norm_sha(base_head),
+        "pr_number": pr_number,
+        "provenance": provenance,
+        "synced_at": synced_at,
+        "synced_by_pid": current_pid,
+        "synced_by": {
+            "username": str(identity or "").strip() or None,
+            "profile": str(profile or "").strip() or None,
+        },
+    }
+    record["synced_pr_head"] = new
+    record["branch_sync"] = sync_block
+    history = record.get("branch_sync_history")
+    if not isinstance(history, list):
+        history = []
+    history = list(history)
+    history.append(sync_block)
+    record["branch_sync_history"] = history
+
+    try:
+        bind_session_lock(
+            record,
+            lock_dir=lock_dir,
+            expected_generation=assessment.get("expected_generation"),
+            renewal_sanctioned=True,
+        )
+    except Exception as exc:  # CAS miss or write failure — partial lifecycle failure
+        result["reasons"].append(
+            f"durable lock head refresh write failed (fail closed): {exc}"
+        )
+        return result
+
+    after = load_issue_lock(
+        remote=remote, org=org, repo=repo, issue_number=issue_number, lock_dir=lock_dir
+    )
+    after_head = _norm_sha((after or {}).get("synced_pr_head"))
+    result["lock_generation_after"] = lock_generation(after)
+    if after_head == new and new is not None:
+        result["refreshed"] = True
+        result["read_after_write_ok"] = True
+        result["reasons"].append(
+            f"durable lock recorded head refreshed to {new} and verified by "
+            "read-after-write"
+        )
+    else:
+        result["reasons"].append(
+            "read-after-write verification failed: durable lock does not record "
+            f"the new head {new} (found {after_head}); partial lifecycle failure"
+        )
+    return result
@@ -145,6 +145,175 @@ def read_head_ancestry(
    return result


+def read_merge_sync_provenance(
+    worktree_path: str,
+    *,
+    prior_head_sha: str | None,
+    synced_head_sha: str | None,
+) -> dict:
+    """Observe whether ``synced_head_sha`` is a sanctioned merge-based branch sync
+    that advanced the PR branch past ``prior_head_sha`` (#871).
+
+    ``gitea_update_pr_branch_by_merge`` advances a PR branch by merging the base
+    branch *into* the branch (``POST /pulls/{n}/update?style=merge``). The result
+    is a merge commit ``M`` on the branch whose **first** parent is the prior
+    branch head and whose second parent is the base tip. When the owning session
+    then dies without the durable lock's recorded head being refreshed, the local
+    worktree still sits at ``prior_head_sha`` while the live PR head is ``M``.
+
+    Recovering that drift safely requires proving the remote head is *exactly*
+    such a merge-sync — not a rewrite, rebase, force-push, or an unrelated
+    commit. This is that server-side observation. It reports facts only; the
+    disposition lives in ``issue_lock_recovery``. Every field is read from git in
+    the declared worktree — nothing is supplied by, or reachable from, an MCP
+    caller (#871).
+
+    Provenance is proven only when ALL hold:
+
+    * both commits are present (a rewritten/force-moved prior head leaves the
+      object graph and fails closed);
+    * ``prior_head_sha`` is a strict ancestor of ``synced_head_sha`` (the branch
+      history is preserved, never replaced);
+    * ``synced_head_sha`` is a merge commit (two or more parents), i.e. a base
+      merged in — a plain fast-forward of new direct commits is not a sync;
+    * ``prior_head_sha`` is an ancestor of the merge's **first** parent, so the
+      branch mainline (first-parent lineage) still reaches the prior head — a
+      rebase/force-push that re-authored the branch side fails this.
+    """
+    path = (worktree_path or "").strip()
+    prior = (prior_head_sha or "").strip()
+    synced = (synced_head_sha or "").strip()
+    result: dict = {
+        "prior_head_sha": prior or None,
+        "synced_head_sha": synced or None,
+        "probe_ok": False,
+        "prior_present": False,
+        "synced_present": False,
+        "prior_is_ancestor": False,
+        "synced_is_merge": False,
+        "first_parent_reaches_prior": False,
+        "is_merge_sync": False,
+        "first_parent_sha": None,
+        "parent_count": None,
+        "proof": None,
+        "reasons": [],
+    }
+    if not path or not prior or not synced:
+        result["reasons"].append(
+            "merge-sync provenance probe requires a worktree path and both "
+            "commit SHAs"
+        )
+        return result
+    if prior == synced:
+        result["reasons"].append(
+            "prior and synced heads are identical; no branch sync occurred"
+        )
+        return result
+
+    def _present(sha: str) -> bool:
+        res = subprocess.run(
+            ["git", "-C", path, "rev-parse", "--verify", "--quiet", f"{sha}^{{commit}}"],
+            capture_output=True,
+            text=True,
+            check=False,
+        )
+        return res.returncode == 0
+
+    def _is_ancestor(ancestor: str, descendant: str) -> bool | None:
+        res = subprocess.run(
+            ["git", "-C", path, "merge-base", "--is-ancestor", ancestor, descendant],
+            capture_output=True,
+            text=True,
+            check=False,
+        )
+        if res.returncode == 0:
+            return True
+        if res.returncode == 1:
+            return False
+        return None  # failed probe — never a silent "no"
+
+    try:
+        result["prior_present"] = _present(prior)
+        result["synced_present"] = _present(synced)
+    except OSError as exc:  # git unavailable — fail closed, never assume
+        result["reasons"].append(f"merge-sync provenance probe could not run: {exc}")
+        return result
+
+    if not result["prior_present"]:
+        result["reasons"].append(
+            f"prior head {prior} is not reachable in '{path}'; history may have "
+            "been rewritten or force-moved"
+        )
+    if not result["synced_present"]:
+        result["reasons"].append(
+            f"synced head {synced} is not reachable in '{path}'"
+        )
+    if not (result["prior_present"] and result["synced_present"]):
+        return result
+
+    ancestor = _is_ancestor(prior, synced)
+    if ancestor is None:
+        result["reasons"].append(
+            "ancestry probe failed; merge-sync provenance unproven"
+        )
+        return result
+    result["prior_is_ancestor"] = bool(ancestor)
+    if not ancestor:
+        result["reasons"].append(
+            f"prior head {prior} is not an ancestor of synced head {synced}; "
+            "the branch history was not preserved (not a merge-based sync)"
+        )
+        return result
+
+    parents_res = subprocess.run(
+        ["git", "-C", path, "rev-list", "--parents", "-n", "1", synced],
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+    if parents_res.returncode != 0:
+        result["reasons"].append(
+            f"could not read parents of {synced}; merge-sync provenance unproven"
+        )
+        return result
+    tokens = (parents_res.stdout or "").split()
+    # tokens[0] is the commit itself; the rest are its parents.
+    parents = tokens[1:]
+    result["parent_count"] = len(parents)
+    result["synced_is_merge"] = len(parents) >= 2
+    if not result["synced_is_merge"]:
+        result["probe_ok"] = True
+        result["reasons"].append(
+            f"synced head {synced} has {len(parents)} parent(s); a merge-based "
+            "branch sync produces a merge commit (two or more parents)"
+        )
+        return result
+    first_parent = parents[0]
+    result["first_parent_sha"] = first_parent
+
+    fp_reaches = _is_ancestor(prior, first_parent) if prior != first_parent else True
+    if fp_reaches is None:
+        result["reasons"].append(
+            "first-parent ancestry probe failed; merge-sync provenance unproven"
+        )
+        return result
+    result["first_parent_reaches_prior"] = bool(fp_reaches)
+    result["probe_ok"] = True
+    if not fp_reaches:
+        result["reasons"].append(
+            f"merge first parent {first_parent} does not reach prior head "
+            f"{prior}; the branch mainline was re-authored (not a sanctioned sync)"
+        )
+        return result
+
+    result["is_merge_sync"] = True
+    result["proof"] = (
+        f"synced head {synced} is a merge commit (parents={len(parents)}) whose "
+        f"first-parent lineage reaches prior head {prior}; base merged into branch"
+    )
+    return result
+
+
 def read_recorded_base(
    worktree_path: str,
    *,
@@ -0,0 +1,475 @@
+"""Inventory and fail-closed guards for MCP restart/reload/kill paths (#657).
+
+Single source of truth enumerating every code/script/doc path that can
+restart, reload, reconnect, kill, or force-recreate an MCP process. Each path
+is classified and linked to the guard that constrains it. The companion
+human-readable inventory lives in ``docs/mcp-restart-path-inventory.md`` and is
+kept in lock-step with this module by ``tests/test_mcp_restart_paths.py``.
+
+Design intent (aligns with #655 restart-coordinator roadmap):
+
+* **No unguarded full restart.** The in-process MCP daemon
+  (``gitea_mcp_server.py`` / ``mcp_server.py`` / ``role_session_router.py``)
+  must never replace or kill its own process — replacing the process after the
+  host wired up the stdio pipes desyncs the JSON-RPC transport (observed with
+  Antigravity/Cascade hosts). ``assert_no_daemon_self_replacement`` enforces
+  this against the live source tree.
+* **No legacy auto-restart helper.** ``_trigger_mcp_auto_restart`` was removed
+  when the stale-runtime resolver became side-effect free (#685);
+  ``assert_auto_restart_helper_absent`` keeps it removed.
+* **Unknown restart attempts fail closed.** LLM tools must route any restart
+  intent through a *registered* path. ``assert_restart_attempt_registered``
+  raises ``UnknownRestartPathError`` for anything not in this inventory.
+* **pkill stays forbidden (#630).** Manual daemon kills are classified as
+  contamination by :mod:`runtime_recovery_guard`; this module records that path
+  and the test asserts the classification still holds.
+
+This module performs no restarts, spawns no threads, and touches no config or
+process state. It is pure inventory + read-only source assertions.
+"""
+
+from __future__ import annotations
+
+import os
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Iterable
+
+# --- Classifications -------------------------------------------------------
+
+#: A narrow, one-shot recovery that is safe by construction (e.g. a CLI wrapper
+#: re-execing into the venv interpreter before importing anything, or an
+#: in-process profile switch). Never targets the running MCP daemon process.
+CLASS_SANCTIONED_NARROW = "sanctioned_narrow_recovery"
+
+#: The path detects a condition that would require a restart, then *fails
+#: closed* on mutations and emits restart/reconnect guidance. It never restarts
+#: the process itself (recovery is owned by the host/operator).
+CLASS_GUARDED_FAIL_CLOSED = "guarded_fail_closed"
+
+#: The path is forbidden. Attempting it is a workflow-safety violation and,
+#: where an LLM tool could invoke it, is marked as contamination.
+CLASS_FORBIDDEN = "forbidden"
+
+#: A previously-existing unguarded restart primitive that has been deleted. A
+#: regression guard keeps it absent.
+CLASS_REMOVED = "removed"
+
+#: Behavior that lives in the host/IDE and is outside this process's control
+#: (e.g. a manual ``/mcp reconnect``). Documented, not code-guarded here.
+CLASS_HOST_RESIDUAL = "host_residual"
+
+VALID_CLASSIFICATIONS = frozenset(
+    {
+        CLASS_SANCTIONED_NARROW,
+        CLASS_GUARDED_FAIL_CLOSED,
+        CLASS_FORBIDDEN,
+        CLASS_REMOVED,
+        CLASS_HOST_RESIDUAL,
+    }
+)
+
+#: The in-process MCP daemon modules. These must never self-replace/self-kill.
+DAEMON_MODULES = (
+    "gitea_mcp_server.py",
+    "mcp_server.py",
+    "role_session_router.py",
+)
+
+#: The legacy auto-restart helper removed in #685. Must stay removed.
+LEGACY_AUTO_RESTART_HELPER = "_trigger_mcp_auto_restart"
+
+#: Call patterns that would let the daemon replace or terminate its own
+#: process. Matched as calls (trailing ``(``) so prose/docstring mentions such
+#: as "we do NOT os.execv() here" or "never calls ``os._exit``" do not trip the
+#: scanner (comment lines are stripped first regardless).
+DAEMON_SELF_REPLACEMENT_PRIMITIVES = (
+    "os.execv(",
+    "os.execve(",
+    "os.execvp(",
+    "os.execvpe(",
+    "os.kill(",
+    "os.killpg(",
+    "os._exit(",
+    "os.abort(",
+)
+
+
+@dataclass(frozen=True)
+class RestartPath:
+    """One classified restart/reload/kill path in the inventory."""
+
+    path_id: str
+    title: str
+    mechanism: str
+    classification: str
+    guard: str
+    locations: tuple[str, ...]
+    references: tuple[str, ...]
+    residual_host: bool = False
+    notes: str = ""
+
+
+class UnknownRestartPathError(RuntimeError):
+    """Raised when a restart attempt is not a registered, classified path."""
+
+
+# --- The inventory ---------------------------------------------------------
+
+_RESTART_PATHS: tuple[RestartPath, ...] = (
+    RestartPath(
+        path_id="cli_venv_bootstrap_execv",
+        title="CLI wrapper venv re-exec",
+        mechanism=(
+            "Standalone CLI scripts re-exec into venv/bin/python3 via os.execv "
+            "at import top, guarded by `sys.executable != venv_python`."
+        ),
+        classification=CLASS_SANCTIONED_NARROW,
+        guard=(
+            "One-shot, pre-import bootstrap; runs before any MCP transport "
+            "exists and only when not already on the venv interpreter, so it "
+            "cannot desync a live daemon. Idempotent guard condition prevents "
+            "a re-exec loop."
+        ),
+        locations=(
+            "create_pr.py",
+            "create_issue.py",
+            "close_issue.py",
+            "merge_pr.py",
+            "review_pr.py",
+            "edit_pr.py",
+            "delete_branch.py",
+            "mark_issue.py",
+            "manage_labels.py",
+            "list_issues.py",
+            "list_prs.py",
+        ),
+        references=("#657",),
+    ),
+    RestartPath(
+        path_id="daemon_self_replacement",
+        title="MCP daemon self-replacement",
+        mechanism=(
+            "The in-process MCP daemon replacing/terminating its own process "
+            "(os.execv/os.kill/os._exit) to reload code."
+        ),
+        classification=CLASS_FORBIDDEN,
+        guard=(
+            "Forbidden by design: replacing the process after the host wired "
+            "up stdio desyncs JSON-RPC (Antigravity/Cascade). Enforced against "
+            "the source tree by assert_no_daemon_self_replacement()."
+        ),
+        locations=("gitea_mcp_server.py:~155 (decision comment)",) + DAEMON_MODULES,
+        references=("#657", "#584"),
+    ),
+    RestartPath(
+        path_id="legacy_auto_restart_helper",
+        title="Legacy _trigger_mcp_auto_restart helper",
+        mechanism=(
+            "A helper that actively restarted the MCP server from the "
+            "read-only resolver path."
+        ),
+        classification=CLASS_REMOVED,
+        guard=(
+            "Removed in #685 when the resolver became side-effect free. Kept "
+            "absent by assert_auto_restart_helper_absent()."
+        ),
+        locations=("gitea_mcp_server.py", "mcp_server.py"),
+        references=("#685", "#657"),
+    ),
+    RestartPath(
+        path_id="config_touch_reload",
+        title="MCP client config-touch reload",
+        mechanism=(
+            "Touching (utime) the MCP client config file to make the host "
+            "reload/recreate the server process."
+        ),
+        classification=CLASS_REMOVED,
+        guard=(
+            "Removed from the resolver in #685: stale-runtime detection is "
+            "report-only and never mutates client config, spawns threads, or "
+            "calls os._exit."
+        ),
+        locations=("gitea_mcp_server.py (resolve_task_capability)",),
+        references=("#685", "#657"),
+    ),
+    RestartPath(
+        path_id="master_advance_auto_restart",
+        title="Master-advance staleness gate",
+        mechanism=(
+            "On-disk master advancing past the running code. The master-parity "
+            "gate detects it and fails mutations closed with restart guidance."
+        ),
+        classification=CLASS_GUARDED_FAIL_CLOSED,
+        guard=(
+            "Detect + fail closed only; the process never self-restarts. "
+            "master_parity_gate captures startup parity and blocks mutations "
+            "while stale, emitting restart/reconnect guidance."
+        ),
+        locations=(
+            "master_parity_gate.py",
+            "gitea_mcp_server.py (gitea_assess_master_parity)",
+        ),
+        references=("#420", "#591", "#657"),
+    ),
+    RestartPath(
+        path_id="stale_runtime_resolver_reconnect",
+        title="Stale-runtime resolver reconnect guidance",
+        mechanism=(
+            "The capability resolver detecting a stale serving process and "
+            "reporting restart_required/stop_required for a client reconnect."
+        ),
+        classification=CLASS_GUARDED_FAIL_CLOSED,
+        guard=(
+            "Report-only (#685): returns restart_required/stop_required and an "
+            "exact_safe_next_action pointing at IDE/client reconnect; performs "
+            "no restart, thread spawn, config touch, or os._exit."
+        ),
+        locations=("gitea_mcp_server.py (gitea_resolve_task_capability)",),
+        references=("#685", "#657"),
+    ),
+    RestartPath(
+        path_id="manual_daemon_kill",
+        title="Manual daemon kill (pkill/killall/kill)",
+        mechanism=(
+            "Shell kills of the MCP daemon: `pkill -f mcp_server.py`, "
+            "`killall`, broad `pkill -f python` sweeps, or `kill <pid>` of a "
+            "daemon pid."
+        ),
+        classification=CLASS_FORBIDDEN,
+        guard=(
+            "Forbidden (#630): runtime_recovery_guard classifies these as "
+            "contamination and gitea_record_daemon_process_kill_attempt writes "
+            "a durable marker that fails subsequent mutations closed. Operator "
+            "maintenance authorization is read only from the environment, not "
+            "from a tool argument."
+        ),
+        locations=(
+            "runtime_recovery_guard.py",
+            "gitea_mcp_server.py (gitea_record_daemon_process_kill_attempt)",
+        ),
+        references=("#630", "#657"),
+    ),
+    RestartPath(
+        path_id="conflict_marker_infra_stop",
+        title="Startup conflict-marker infra stop",
+        mechanism=(
+            "The daemon entrypoint scans for unresolved merge-conflict markers "
+            "at startup and stops (sys.exit(1)) if found."
+        ),
+        classification=CLASS_GUARDED_FAIL_CLOSED,
+        guard=(
+            "Fail-closed startup stop, not a restart: the process exits and "
+            "waits for the operator to resolve conflicts and relaunch. Never "
+            "self-restarts or loops."
+        ),
+        locations=("mcp_server.py (check_conflict_markers)",),
+        references=("#657",),
+    ),
+    RestartPath(
+        path_id="ide_client_reconnect",
+        title="Host/IDE MCP reconnect",
+        mechanism=(
+            "A manual `/mcp reconnect` (or equivalent host action) that the "
+            "IDE performs to recreate the MCP client connection."
+        ),
+        classification=CLASS_HOST_RESIDUAL,
+        guard=(
+            "Outside this process's control. It is the sanctioned recovery the "
+            "gates point operators toward; documented as residual host "
+            "behavior. No in-process code initiates it."
+        ),
+        locations=("host/IDE",),
+        references=("#584", "#656", "#657"),
+        residual_host=True,
+    ),
+    RestartPath(
+        path_id="profile_switch_runtime",
+        title="Runtime profile switch",
+        mechanism=(
+            "Switching the active execution profile at runtime "
+            "(dynamic-profile mode)."
+        ),
+        classification=CLASS_SANCTIONED_NARROW,
+        guard=(
+            "In-process and restart-free: runtime_switching_supported is true, "
+            "so a profile switch rebinds capability without recreating the "
+            "process. No restart primitive is invoked."
+        ),
+        locations=("gitea_mcp_server.py (gitea_activate_profile)",),
+        references=("#656", "#657"),
+    ),
+)
+
+_BY_ID: dict[str, RestartPath] = {p.path_id: p for p in _RESTART_PATHS}
+
+
+# --- Read-only accessors ---------------------------------------------------
+
+
+def iter_restart_paths() -> tuple[RestartPath, ...]:
+    """Return the full inventory as an immutable tuple."""
+
+    return _RESTART_PATHS
+
+
+def restart_path_ids() -> frozenset[str]:
+    """Return the set of registered path ids."""
+
+    return frozenset(_BY_ID)
+
+
+def get_restart_path(path_id: str) -> RestartPath:
+    """Return the registered path, or raise :class:`UnknownRestartPathError`."""
+
+    try:
+        return _BY_ID[path_id]
+    except KeyError as exc:
+        raise UnknownRestartPathError(
+            f"unknown restart path id {path_id!r}; not in the #657 inventory"
+        ) from exc
+
+
+def paths_by_classification(classification: str) -> tuple[RestartPath, ...]:
+    """Return all registered paths with the given classification."""
+
+    if classification not in VALID_CLASSIFICATIONS:
+        raise ValueError(f"unknown classification {classification!r}")
+    return tuple(p for p in _RESTART_PATHS if p.classification == classification)
+
+
+def assert_restart_attempt_registered(path_id: str) -> RestartPath:
+    """Fail closed unless ``path_id`` is a registered, classified restart path.
+
+    LLM tools that intend to trigger any restart/reload/reconnect must name a
+    registered path so an unknown/novel restart primitive cannot slip through
+    silently. Forbidden and removed paths are registered too — this only
+    asserts the attempt is *known*, not that it is *permitted*; callers must
+    still honor the classification.
+    """
+
+    return get_restart_path(path_id)
+
+
+def assert_registry_wellformed() -> None:
+    """Validate the inventory's own invariants (fail closed on drift)."""
+
+    seen: set[str] = set()
+    for path in _RESTART_PATHS:
+        if path.path_id in seen:
+            raise ValueError(f"duplicate restart path id {path.path_id!r}")
+        seen.add(path.path_id)
+        if path.classification not in VALID_CLASSIFICATIONS:
+            raise ValueError(
+                f"{path.path_id!r} has invalid classification "
+                f"{path.classification!r}"
+            )
+        if not path.guard.strip():
+            raise ValueError(f"{path.path_id!r} is missing a guard description")
+        if not path.references:
+            raise ValueError(f"{path.path_id!r} is missing references")
+        if not path.locations:
+            raise ValueError(f"{path.path_id!r} is missing locations")
+        if path.classification == CLASS_HOST_RESIDUAL and not path.residual_host:
+            raise ValueError(
+                f"{path.path_id!r} is host_residual but residual_host is False"
+            )
+
+
+# --- Source-tree guards ----------------------------------------------------
+
+
+def _repo_root(root: str | os.PathLike[str] | None = None) -> Path:
+    if root is not None:
+        return Path(root)
+    return Path(__file__).resolve().parent
+
+
+def _iter_code_lines(text: str) -> Iterable[tuple[int, str]]:
+    """Yield (1-based lineno, line) for lines that are not full-line comments."""
+
+    for lineno, line in enumerate(text.splitlines(), start=1):
+        if line.lstrip().startswith("#"):
+            continue
+        yield lineno, line
+
+
+def scan_daemon_self_replacement(
+    root: str | os.PathLike[str] | None = None,
+) -> list[dict[str, object]]:
+    """Return violations where a daemon module could self-replace/self-kill.
+
+    Scans :data:`DAEMON_MODULES` for calls in
+    :data:`DAEMON_SELF_REPLACEMENT_PRIMITIVES`. Full-line comments are ignored,
+    and only call forms (with a trailing ``(``) match, so decision comments and
+    docstrings that merely mention the primitives do not produce false hits.
+    """
+
+    repo = _repo_root(root)
+    violations: list[dict[str, object]] = []
+    for module in DAEMON_MODULES:
+        path = repo / module
+        if not path.exists():
+            continue
+        text = path.read_text(encoding="utf-8", errors="replace")
+        for lineno, line in _iter_code_lines(text):
+            for primitive in DAEMON_SELF_REPLACEMENT_PRIMITIVES:
+                if primitive in line:
+                    violations.append(
+                        {
+                            "module": module,
+                            "line": lineno,
+                            "primitive": primitive,
+                            "text": line.strip(),
+                        }
+                    )
+    return violations
+
+
+def assert_no_daemon_self_replacement(
+    root: str | os.PathLike[str] | None = None,
+) -> None:
+    """Fail closed if any daemon module can restart/kill its own process."""
+
+    violations = scan_daemon_self_replacement(root)
+    if violations:
+        rendered = "; ".join(
+            f"{v['module']}:{v['line']} {v['primitive']}" for v in violations
+        )
+        raise AssertionError(
+            "MCP daemon must never self-replace/self-kill (#657); found: "
+            f"{rendered}"
+        )
+
+
+def scan_auto_restart_helper(
+    root: str | os.PathLike[str] | None = None,
+) -> list[dict[str, object]]:
+    """Return occurrences of a *definition* of the legacy auto-restart helper."""
+
+    repo = _repo_root(root)
+    needle = f"def {LEGACY_AUTO_RESTART_HELPER}"
+    hits: list[dict[str, object]] = []
+    for module in DAEMON_MODULES:
+        path = repo / module
+        if not path.exists():
+            continue
+        text = path.read_text(encoding="utf-8", errors="replace")
+        for lineno, line in _iter_code_lines(text):
+            if needle in line:
+                hits.append({"module": module, "line": lineno})
+    return hits
+
+
+def assert_auto_restart_helper_absent(
+    root: str | os.PathLike[str] | None = None,
+) -> None:
+    """Fail closed if the removed ``_trigger_mcp_auto_restart`` reappears."""
+
+    hits = scan_auto_restart_helper(root)
+    if hits:
+        rendered = "; ".join(f"{h['module']}:{h['line']}" for h in hits)
+        raise AssertionError(
+            f"{LEGACY_AUTO_RESTART_HELPER} was removed in #685 and must not "
+            f"return (#657); found definition at: {rendered}"
+        )
@@ -566,6 +566,10 @@ def build_pr_cleanup_entry(
        worktree_state=worktree_state,
        active_lock=active_lock,
    )
+    planned = plan_cleanup_execution_order(
+        remote_assessment=remote,
+        local_assessment=local,
+    )
    return {
        "pr_number": pr_number,
        "issue_number": issue_number,
@@ -576,9 +580,63 @@ def build_pr_cleanup_entry(
        "merged": merged,
        "remote_branch": remote,
        "local_worktree": local,
+        # #851: dry-run and execute share the same lifecycle order description.
+        "planned_execution_order": planned,
    }


+def plan_cleanup_execution_order(
+    *,
+    remote_assessment: dict[str, Any] | None,
+    local_assessment: dict[str, Any] | None,
+) -> list[dict[str, Any]]:
+    """Describe independent worktree-then-reassess-then-remote cleanup order (#851).
+
+    Remote ownership protection remains fail-closed at execute time. A worktree
+    that is independently safe to remove is never skipped merely because remote
+    deletion may be blocked by that same ``worktree_binding``.
+    """
+    remote = remote_assessment or {}
+    local = local_assessment or {}
+    steps: list[dict[str, Any]] = []
+    worktree_safe = bool(local.get("safe_to_remove_worktree"))
+    remote_safe = bool(remote.get("safe_to_delete_remote"))
+
+    if worktree_safe:
+        steps.append(
+            {
+                "action": "remove_local_worktree",
+                "reason": "independently_safe_to_remove",
+                "phase": 1,
+            }
+        )
+    if remote_safe:
+        if worktree_safe:
+            steps.append(
+                {
+                    "action": "reassess_branch_ownership",
+                    "reason": "after_worktree_removal_clear_worktree_binding",
+                    "phase": 2,
+                }
+            )
+            steps.append(
+                {
+                    "action": "delete_remote_branch",
+                    "reason": "only_if_independently_safe_after_reassessment",
+                    "phase": 3,
+                }
+            )
+        else:
+            steps.append(
+                {
+                    "action": "delete_remote_branch",
+                    "reason": "safe_to_delete_and_no_independent_worktree_removal",
+                    "phase": 1,
+                }
+            )
+    return steps
+
+
 def build_reconciliation_report(
    *,
    project_root: str,
@@ -32,6 +32,17 @@ TASK_CAPABILITY_MAP: dict[str, dict[str, str]] = {
        "permission": "gitea.issue.comment",
        "role": "author",
    },
+    # #864: dirty-preserving same-claimant author-session rebind (dead owner PID).
+    # Author MCP tool path. Reconciler execute is gated inside the tool via
+    # authorize_reconciler_execute + role_kind checks (not this map entry).
+    "rebind_dirty_same_claimant_author_session": {
+        "permission": "gitea.issue.comment",
+        "role": "author",
+    },
+    "gitea_rebind_dirty_same_claimant_author_session": {
+        "permission": "gitea.issue.comment",
+        "role": "author",
+    },
    "set_issue_labels": {
        "permission": "gitea.issue.comment",
        "role": "author",
@@ -1266,6 +1266,730 @@ class TestSecondRemediationIntegration(unittest.TestCase):
        self.assertIn("delete_acknowledged", delete_actions[0])
        self.assertTrue(delete_actions[0].get("verified_absent"))

+    def test_issue_851_worktree_removed_when_remote_blocked_only_by_worktree_binding(self):
+        """#851: remote blocked by worktree_binding must not skip safe worktree removal.
+
+        Lifecycle: remove clean owned worktree → reassess ownership → delete
+        remote only if independently safe. Unrelated entries stay untouched.
+        """
+        from mcp_server import gitea_reconcile_merged_cleanups
+
+        target_branch = "fix/issue-844-exclude-epic-containers"
+        foreign_branch = "fix/issue-999-unrelated-active"
+        worktree_path = "/tmp/branches/fix-issue-844-exclude-epic-containers"
+        ownership_calls = []
+        remove_calls = []
+        delete_api_calls = []
+
+        def fake_collect(**kwargs):
+            ownership_calls.append(dict(kwargs))
+            # Ownership is reassessed *after* independent worktree removal (#851).
+            # Target worktree is already gone → no worktree_binding remains.
+            # Foreign branch keeps an active author lease → remote delete blocked.
+            if kwargs.get("branch") == foreign_branch:
+                # Match session-bound org/repo + host used by the tool resolve path.
+                return {
+                    "records": [
+                        {
+                            "category": guard.OWNERSHIP_CATEGORY_AUTHOR_LEASE,
+                            "status": "active",
+                            "remote": kwargs.get("remote") or "prgs",
+                            "host": kwargs.get("host") or "gitea.example.com",
+                            "org": kwargs.get("org") or "Scaled-Tech-Consulting",
+                            "repo": kwargs.get("repo") or "Gitea-Tools",
+                            "branch": foreign_branch,
+                            "reclaim_allowed": False,
+                        }
+                    ],
+                    "inventory_error": False,
+                }
+            return {"records": [], "inventory_error": False}
+
+        def fake_remove(project_root, branch, worktree_path=None):
+            remove_calls.append(
+                {"branch": branch, "worktree_path": worktree_path}
+            )
+            return {
+                "success": True,
+                "performed": True,
+                "message": f"removed worktree {worktree_path}",
+                "worktree_path": worktree_path,
+            }
+
+        def fake_probe(h, o, r, auth, br):
+            return guard.classify_branch_readback_http_status(
+                404, not_found_scope=guard.NOT_FOUND_SCOPE_BRANCH
+            )
+
+        def fake_api(method, url, auth, **kwargs):
+            if method == "DELETE":
+                delete_api_calls.append(url)
+            return {}
+
+        report = {
+            "entries": [
+                {
+                    "pr_number": 848,
+                    "head_branch": target_branch,
+                    "remote_branch": {"safe_to_delete_remote": True},
+                    "local_worktree": {
+                        "safe_to_remove_worktree": True,
+                        "worktree_path": worktree_path,
+                    },
+                },
+                {
+                    "pr_number": 999,
+                    "head_branch": foreign_branch,
+                    "remote_branch": {"safe_to_delete_remote": True},
+                    "local_worktree": {
+                        "safe_to_remove_worktree": False,
+                        "worktree_path": None,
+                    },
+                },
+            ],
+            "reviewer_scratch_entries": [],
+        }
+        patch(
+            "mcp_server.get_profile",
+            return_value={
+                "profile_name": "prgs-reconciler",
+                "role": "reconciler",
+                "allowed_operations": [
+                    "gitea.read",
+                    "gitea.branch.delete",
+                    "gitea.pr.close",
+                ],
+                "forbidden_operations": [],
+            },
+        ).start()
+        patch("mcp_server.api_get_all", return_value=[]).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.build_reconciliation_report",
+            return_value=report,
+        ).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.discover_reviewer_scratch_worktrees",
+            return_value=[],
+        ).start()
+        patch(
+            "mcp_server.audit_reconciliation_mode.check_cleanup_execution_allowed",
+            return_value=(True, []),
+        ).start()
+        patch("mcp_server.verify_preflight_purity", return_value=None).start()
+        patch(
+            "mcp_server._collect_branch_ownership_records",
+            side_effect=fake_collect,
+        ).start()
+        patch("mcp_server._probe_remote_branch", side_effect=fake_probe).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.remove_local_worktree",
+            side_effect=fake_remove,
+        ).start()
+        self.mock_api.side_effect = fake_api
+
+        res = gitea_reconcile_merged_cleanups(
+            dry_run=False,
+            execute_confirmed=True,
+            remote="prgs",
+        )
+        self.assertTrue(res.get("performed") or res.get("executed"))
+        actions = res.get("actions") or []
+
+        remove_actions = [
+            a for a in actions if a.get("action") == "remove_local_worktree"
+        ]
+        self.assertEqual(len(remove_actions), 1, actions)
+        self.assertTrue(remove_actions[0].get("success"))
+        self.assertEqual(remove_calls[0]["branch"], target_branch)
+        self.assertEqual(remove_calls[0]["worktree_path"], worktree_path)
+
+        # Target remote delete succeeds after worktree removal + reassessment.
+        target_deletes = [
+            a
+            for a in actions
+            if a.get("action") == "delete_remote_branch"
+            and a.get("branch") == target_branch
+        ]
+        self.assertEqual(len(target_deletes), 1, actions)
+        self.assertTrue(target_deletes[0].get("success"))
+        self.assertTrue(target_deletes[0].get("after_worktree_removal"))
+        self.assertTrue(target_deletes[0].get("ownership_reassessed"))
+        self.assertTrue(target_deletes[0].get("verified_absent"))
+
+        # Foreign branch remains protected (author lease) and is not deleted.
+        foreign_deletes = [
+            a
+            for a in actions
+            if a.get("action") == "delete_remote_branch"
+            and a.get("branch") == foreign_branch
+        ]
+        self.assertEqual(len(foreign_deletes), 1, actions)
+        self.assertFalse(foreign_deletes[0].get("success"))
+        self.assertEqual(
+            foreign_deletes[0].get("blocker_kind"), "active_branch_ownership"
+        )
+        self.assertIn(
+            guard.OWNERSHIP_CATEGORY_AUTHOR_LEASE,
+            foreign_deletes[0].get("blocking_categories") or [],
+        )
+        # Only the target branch should hit the DELETE API.
+        self.assertEqual(len(delete_api_calls), 1)
+
+        # Ownership collected for target (post-removal) and foreign; worktree
+        # removal happened before target remote delete in the action log.
+        target_idx = next(
+            i
+            for i, a in enumerate(actions)
+            if a.get("action") == "remove_local_worktree"
+        )
+        delete_idx = next(
+            i
+            for i, a in enumerate(actions)
+            if a.get("action") == "delete_remote_branch"
+            and a.get("branch") == target_branch
+            and a.get("success")
+        )
+        self.assertLess(target_idx, delete_idx)
+
+    def test_issue_851_dirty_worktree_not_removed_and_remote_stays_protected(self):
+        """#851: dirty/foreign worktrees remain protected; no unsafe cleanup."""
+        from mcp_server import gitea_reconcile_merged_cleanups
+
+        branch = "fix/issue-851-dirty"
+        remove_calls = []
+
+        def fake_collect(**kwargs):
+            return {
+                "records": [
+                    {
+                        "category": guard.OWNERSHIP_CATEGORY_WORKTREE_BINDING,
+                        "status": "active",
+                        "remote": kwargs.get("remote") or "prgs",
+                        "host": kwargs.get("host") or "gitea.example.com",
+                        "org": kwargs.get("org") or "Scaled-Tech-Consulting",
+                        "repo": kwargs.get("repo") or "Gitea-Tools",
+                        "branch": branch,
+                        "reclaim_allowed": False,
+                    }
+                ],
+                "inventory_error": False,
+            }
+
+        report = {
+            "entries": [
+                {
+                    "pr_number": 851,
+                    "head_branch": branch,
+                    "remote_branch": {"safe_to_delete_remote": True},
+                    "local_worktree": {
+                        "safe_to_remove_worktree": False,
+                        "worktree_path": "/tmp/dirty-wt",
+                    },
+                }
+            ],
+            "reviewer_scratch_entries": [],
+        }
+        patch(
+            "mcp_server.get_profile",
+            return_value={
+                "profile_name": "prgs-reconciler",
+                "role": "reconciler",
+                "allowed_operations": [
+                    "gitea.read",
+                    "gitea.branch.delete",
+                ],
+                "forbidden_operations": [],
+            },
+        ).start()
+        patch("mcp_server.api_get_all", return_value=[]).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.build_reconciliation_report",
+            return_value=report,
+        ).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.discover_reviewer_scratch_worktrees",
+            return_value=[],
+        ).start()
+        patch(
+            "mcp_server.audit_reconciliation_mode.check_cleanup_execution_allowed",
+            return_value=(True, []),
+        ).start()
+        patch("mcp_server.verify_preflight_purity", return_value=None).start()
+        patch(
+            "mcp_server._collect_branch_ownership_records",
+            side_effect=fake_collect,
+        ).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.remove_local_worktree",
+            side_effect=lambda *a, **k: remove_calls.append(k) or {
+                "success": True,
+                "performed": True,
+            },
+        ).start()
+        self.mock_api.side_effect = lambda *a, **k: {}
+
+        res = gitea_reconcile_merged_cleanups(
+            dry_run=False,
+            execute_confirmed=True,
+            remote="prgs",
+        )
+        actions = res.get("actions") or []
+        self.assertEqual(remove_calls, [])
+        self.assertFalse(
+            any(a.get("action") == "remove_local_worktree" for a in actions)
+        )
+        deletes = [
+            a for a in actions if a.get("action") == "delete_remote_branch"
+        ]
+        self.assertEqual(len(deletes), 1)
+        self.assertFalse(deletes[0].get("success"))
+        self.assertEqual(deletes[0].get("blocker_kind"), "active_branch_ownership")
+        self.assertIn(
+            guard.OWNERSHIP_CATEGORY_WORKTREE_BINDING,
+            deletes[0].get("blocking_categories") or [],
+        )
+
+    def test_issue_851_idempotent_resume_when_worktree_already_absent(self):
+        """#851: partial failures remain resumable and idempotent."""
+        from mcp_server import gitea_reconcile_merged_cleanups
+
+        branch = "fix/issue-851-resume"
+        ownership_calls = []
+
+        def fake_collect(**kwargs):
+            ownership_calls.append(kwargs)
+            return {"records": [], "inventory_error": False}
+
+        def fake_remove(project_root, branch, worktree_path=None):
+            return {
+                "success": False,
+                "performed": False,
+                "message": f"worktree not found: {worktree_path}",
+            }
+
+        def fake_probe(h, o, r, auth, br):
+            return guard.classify_branch_readback_http_status(
+                404, not_found_scope=guard.NOT_FOUND_SCOPE_BRANCH
+            )
+
+        report = {
+            "entries": [
+                {
+                    "pr_number": 851,
+                    "head_branch": branch,
+                    "remote_branch": {"safe_to_delete_remote": True},
+                    "local_worktree": {
+                        "safe_to_remove_worktree": True,
+                        "worktree_path": "/tmp/already-gone",
+                    },
+                }
+            ],
+            "reviewer_scratch_entries": [],
+        }
+        patch(
+            "mcp_server.get_profile",
+            return_value={
+                "profile_name": "prgs-reconciler",
+                "role": "reconciler",
+                "allowed_operations": [
+                    "gitea.read",
+                    "gitea.branch.delete",
+                ],
+                "forbidden_operations": [],
+            },
+        ).start()
+        patch("mcp_server.api_get_all", return_value=[]).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.build_reconciliation_report",
+            return_value=report,
+        ).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.discover_reviewer_scratch_worktrees",
+            return_value=[],
+        ).start()
+        patch(
+            "mcp_server.audit_reconciliation_mode.check_cleanup_execution_allowed",
+            return_value=(True, []),
+        ).start()
+        patch("mcp_server.verify_preflight_purity", return_value=None).start()
+        patch(
+            "mcp_server._collect_branch_ownership_records",
+            side_effect=fake_collect,
+        ).start()
+        patch("mcp_server._probe_remote_branch", side_effect=fake_probe).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.remove_local_worktree",
+            side_effect=fake_remove,
+        ).start()
+        self.mock_api.side_effect = lambda *a, **k: {}
+
+        res = gitea_reconcile_merged_cleanups(
+            dry_run=False,
+            execute_confirmed=True,
+            remote="prgs",
+        )
+        actions = res.get("actions") or []
+        removes = [a for a in actions if a.get("action") == "remove_local_worktree"]
+        deletes = [a for a in actions if a.get("action") == "delete_remote_branch"]
+        self.assertEqual(len(removes), 1)
+        self.assertFalse(removes[0].get("success"))
+        self.assertEqual(len(deletes), 1)
+        self.assertTrue(deletes[0].get("success"))
+        self.assertTrue(deletes[0].get("after_worktree_removal"))
+        self.assertTrue(ownership_calls)
+
+
+class TestIssue855ExactPrSelector(unittest.TestCase):
+    """#855: exact pr_number pin for reconcile_merged_cleanups (#851 lifecycle)."""
+
+    def setUp(self):
+        self._remotes = patch.dict(
+            mcp_server.REMOTES,
+            {
+                "prgs": {
+                    "host": "gitea.example.com",
+                    "org": "Scaled-Tech-Consulting",
+                    "repo": "Gitea-Tools",
+                }
+            },
+        )
+        self._remotes.start()
+        patch("gitea_audit.audit_enabled", return_value=False).start()
+        self.mock_api = patch("mcp_server.api_request").start()
+        self.mock_all = patch("mcp_server.api_get_all", return_value=[]).start()
+        patch("mcp_server.get_auth_header", return_value=FAKE_AUTH).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.is_head_ancestor_of_ref",
+            return_value=True,
+        ).start()
+        patch(
+            "mcp_server.get_profile",
+            return_value=dict(RECONCILER_WITH_DELETE),
+        ).start()
+        patch(
+            "mcp_server._profile_operation_gate",
+            return_value=[],
+        ).start()
+        patch(
+            "mcp_server._collect_branch_ownership_records",
+            return_value={"records": [], "inventory_error": False},
+        ).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.discover_reviewer_scratch_worktrees",
+            return_value=[],
+        ).start()
+        patch("mcp_server.verify_preflight_purity", return_value=None).start()
+        patch(
+            "mcp_server.audit_reconciliation_mode.check_cleanup_execution_allowed",
+            return_value=(True, []),
+        ).start()
+
+    def tearDown(self):
+        patch.stopall()
+
+    def _merged_pr(self, number, branch, sha="c" * 40):
+        return {
+            "number": number,
+            "title": f"PR {number}",
+            "body": f"Closes #{number - 4}",
+            "merged": True,
+            "merged_at": "2026-07-23T12:00:00Z",
+            "merge_commit_sha": "f" * 40,
+            "state": "closed",
+            "head": {"ref": branch, "sha": sha},
+            "base": {"ref": "master"},
+        }
+
+    def test_exact_pr_848_ignores_newer_852_in_batch_queue(self):
+        """pr_number=848 selects only #848 even when #852 is newer/first."""
+        from mcp_server import gitea_reconcile_merged_cleanups
+
+        pr_848 = self._merged_pr(
+            848, "fix/issue-844-exclude-epic-containers", sha="c3f282ba" + "0" * 32
+        )
+        # Closed list would rank #852 first in batch mode; exact pin must ignore it.
+        closed_batch = [
+            self._merged_pr(852, "fix/issue-851-cleanup-worktree-before-remote-delete"),
+            pr_848,
+            self._merged_pr(849, "fix/issue-849-other"),
+            self._merged_pr(846, "fix/issue-846-other"),
+            self._merged_pr(845, "fix/issue-845-other"),
+        ]
+        batch_fetch_calls = []
+
+        def fake_api(method, url, *args, **kwargs):
+            if method == "GET" and url.rstrip("/").endswith("/pulls/848"):
+                return dict(pr_848)
+            if method == "GET" and "/pulls/" in url:
+                raise AssertionError(f"unexpected PR fetch: {url}")
+            if method == "GET" and "/branches/" in url:
+                return {"name": "present"}
+            return {}
+
+        def fake_all(url, auth, limit=None):
+            batch_fetch_calls.append((url, limit))
+            if "state=open" in url:
+                return []
+            if "state=closed" in url:
+                # Exact mode must not use the closed batch list.
+                raise AssertionError(
+                    "exact pr_number mode must not page closed PRs: " + url
+                )
+            return []
+
+        self.mock_api.side_effect = fake_api
+        self.mock_all.side_effect = fake_all
+        patch(
+            "mcp_server._remote_branch_exists",
+            return_value=True,
+        ).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.build_reconciliation_report",
+            side_effect=lambda **kwargs: {
+                "entries": [
+                    {
+                        "pr_number": int(pr["number"]),
+                        "head_branch": (pr.get("head") or {}).get("ref"),
+                        "issue_number": 844,
+                        "remote_branch": {
+                            "safe_to_delete_remote": True,
+                            "head_branch": (pr.get("head") or {}).get("ref"),
+                        },
+                        "local_worktree": {
+                            "safe_to_remove_worktree": True,
+                            "worktree_path": (
+                                "/tmp/branches/fix-issue-844-exclude-epic-containers"
+                            ),
+                        },
+                        "planned_execution_order": (
+                            mcp_server.merged_cleanup_reconcile.plan_cleanup_execution_order(
+                                remote_assessment={"safe_to_delete_remote": True},
+                                local_assessment={"safe_to_remove_worktree": True},
+                            )
+                        ),
+                    }
+                    for pr in kwargs.get("closed_prs") or []
+                    if pr.get("merged_at") or pr.get("merged")
+                ],
+                "reviewer_scratch_entries": [],
+                "merged_pr_count": len(kwargs.get("closed_prs") or []),
+            },
+        ).start()
+
+        res = gitea_reconcile_merged_cleanups(
+            dry_run=True,
+            pr_number=848,
+            remote="prgs",
+            org="Scaled-Tech-Consulting",
+            repo="Gitea-Tools",
+        )
+        self.assertTrue(res.get("success"))
+        self.assertFalse(res.get("performed"))
+        self.assertEqual(res.get("selection_mode"), "exact_pr")
+        self.assertEqual(res.get("selected_pr_number"), 848)
+        entries = res.get("entries") or []
+        self.assertEqual(len(entries), 1, entries)
+        self.assertEqual(entries[0].get("pr_number"), 848)
+        self.assertEqual(
+            entries[0].get("head_branch"),
+            "fix/issue-844-exclude-epic-containers",
+        )
+        # No other PR appears in plan.
+        self.assertEqual(list((res.get("planned_execution_orders") or {}).keys()), ["848"])
+        plan = (res.get("planned_execution_orders") or {}).get("848") or []
+        actions = [s.get("action") for s in plan]
+        self.assertEqual(
+            actions,
+            [
+                "remove_local_worktree",
+                "reassess_branch_ownership",
+                "delete_remote_branch",
+            ],
+        )
+        # Prove we never scanned the multi-PR closed batch.
+        self.assertFalse(any("state=closed" in (u or "") for u, _ in batch_fetch_calls))
+        # closed_batch fixture must remain unused (sanity).
+        self.assertEqual(closed_batch[0]["number"], 852)
+
+    def test_exact_pr_execute_only_mutates_selected_pr(self):
+        """Execute with pr_number must never touch #845/#846/#849/#852."""
+        from mcp_server import gitea_reconcile_merged_cleanups
+
+        pr_848 = self._merged_pr(848, "fix/issue-844-exclude-epic-containers")
+        worktree_path = "/tmp/branches/fix-issue-844-exclude-epic-containers"
+        remove_calls = []
+        delete_api_calls = []
+        ownership_branches = []
+
+        def fake_api(method, url, *args, **kwargs):
+            if method == "GET" and url.rstrip("/").endswith("/pulls/848"):
+                return dict(pr_848)
+            if method == "DELETE":
+                delete_api_calls.append(url)
+                # Forbid foreign PR branch deletion by URL content.
+                for forbidden in ("845", "846", "849", "852"):
+                    self.assertNotIn(forbidden, url)
+            return {}
+
+        def fake_remove(project_root, branch, worktree_path=None):
+            remove_calls.append({"branch": branch, "worktree_path": worktree_path})
+            return {
+                "success": True,
+                "performed": True,
+                "message": f"removed {worktree_path}",
+                "worktree_path": worktree_path,
+            }
+
+        def fake_collect(**kwargs):
+            ownership_branches.append(kwargs.get("branch"))
+            return {"records": [], "inventory_error": False}
+
+        def fake_probe(h, o, r, auth, br):
+            return guard.classify_branch_readback_http_status(
+                404, not_found_scope=guard.NOT_FOUND_SCOPE_BRANCH
+            )
+
+        self.mock_api.side_effect = fake_api
+        self.mock_all.side_effect = lambda url, auth, limit=None: []
+        patch("mcp_server._remote_branch_exists", return_value=True).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.build_reconciliation_report",
+            return_value={
+                "entries": [
+                    {
+                        "pr_number": 848,
+                        "head_branch": "fix/issue-844-exclude-epic-containers",
+                        "remote_branch": {"safe_to_delete_remote": True},
+                        "local_worktree": {
+                            "safe_to_remove_worktree": True,
+                            "worktree_path": worktree_path,
+                        },
+                        "planned_execution_order": [
+                            {"action": "remove_local_worktree", "phase": 1},
+                            {"action": "reassess_branch_ownership", "phase": 2},
+                            {"action": "delete_remote_branch", "phase": 3},
+                        ],
+                    }
+                ],
+                "reviewer_scratch_entries": [
+                    # Foreign scratch must be filtered before report execute loop;
+                    # if present here it would still be a test failure if acted on.
+                ],
+                "merged_pr_count": 1,
+            },
+        ).start()
+        patch(
+            "mcp_server.merged_cleanup_reconcile.remove_local_worktree",
+            side_effect=fake_remove,
+        ).start()
+        patch(
+            "mcp_server._collect_branch_ownership_records",
+            side_effect=fake_collect,
+        ).start()
+        patch("mcp_server._probe_remote_branch", side_effect=fake_probe).start()
+
+        res = gitea_reconcile_merged_cleanups(
+            dry_run=False,
+            execute_confirmed=True,
+            pr_number=848,
+            remote="prgs",
+            org="Scaled-Tech-Consulting",
+            repo="Gitea-Tools",
+        )
+        self.assertTrue(res.get("performed") or res.get("executed"))
+        self.assertEqual(res.get("selection_mode"), "exact_pr")
+        self.assertEqual(res.get("selected_pr_number"), 848)
+        actions = res.get("actions") or []
+        pr_numbers_touched = {
+            a.get("pr_number") for a in actions if a.get("pr_number") is not None
+        }
+        self.assertTrue(pr_numbers_touched.issubset({None, 848}) or not pr_numbers_touched)
+        removes = [a for a in actions if a.get("action") == "remove_local_worktree"]
+        deletes = [a for a in actions if a.get("action") == "delete_remote_branch"]
+        self.assertEqual(len(removes), 1)
+        self.assertEqual(remove_calls[0]["branch"], "fix/issue-844-exclude-epic-containers")
+        self.assertEqual(len(deletes), 1)
+        self.assertTrue(deletes[0].get("success"))
+        self.assertTrue(deletes[0].get("after_worktree_removal"))
+        self.assertEqual(len(delete_api_calls), 1)
+        self.assertEqual(
+            ownership_branches, ["fix/issue-844-exclude-epic-containers"]
+        )
+
+    def test_exact_pr_unknown_fails_closed_without_mutation(self):
+        from mcp_server import gitea_reconcile_merged_cleanups
+
+        def fake_api(method, url, *args, **kwargs):
+            if method == "GET" and "/pulls/99999" in url:
+                raise RuntimeError("HTTP 404 Not Found")
+            raise AssertionError(f"unexpected API call {method} {url}")
+
+        self.mock_api.side_effect = fake_api
+        res = gitea_reconcile_merged_cleanups(
+            dry_run=True,
+            pr_number=99999,
+            remote="prgs",
+        )
+        self.assertFalse(res.get("success"))
+        self.assertFalse(res.get("performed"))
+        self.assertEqual(res.get("blocker_kind"), "pr_unresolvable")
+        self.assertIn("99999", " ".join(res.get("reasons") or []))
+
+    def test_exact_pr_not_merged_fails_closed(self):
+        from mcp_server import gitea_reconcile_merged_cleanups
+
+        def fake_api(method, url, *args, **kwargs):
+            if method == "GET" and url.rstrip("/").endswith("/pulls/900"):
+                return {
+                    "number": 900,
+                    "merged": False,
+                    "merged_at": None,
+                    "state": "open",
+                    "head": {"ref": "feat/x", "sha": "a" * 40},
+                }
+            raise AssertionError(f"unexpected {method} {url}")
+
+        self.mock_api.side_effect = fake_api
+        res = gitea_reconcile_merged_cleanups(
+            dry_run=False,
+            execute_confirmed=True,
+            pr_number=900,
+            remote="prgs",
+        )
+        self.assertFalse(res.get("success"))
+        self.assertFalse(res.get("performed"))
+        self.assertEqual(res.get("blocker_kind"), "pr_not_merged")
+
+    def test_exact_pr_invalid_number_fails_closed(self):
+        from mcp_server import gitea_reconcile_merged_cleanups
+
+        res = gitea_reconcile_merged_cleanups(
+            dry_run=True,
+            pr_number=0,
+            remote="prgs",
+        )
+        self.assertFalse(res.get("success"))
+        self.assertEqual(res.get("blocker_kind"), "invalid_pr_number")
+        self.mock_api.assert_not_called()
+
+    def test_batch_mode_still_works_without_pr_number(self):
+        """Unfiltered batch path remains backward compatible."""
+        from mcp_server import gitea_reconcile_merged_cleanups
+
+        self.mock_all.side_effect = lambda url, auth, limit=None: []
+        self.mock_api.side_effect = lambda *a, **k: {}
+        patch(
+            "mcp_server.merged_cleanup_reconcile.build_reconciliation_report",
+            return_value={
+                "entries": [],
+                "reviewer_scratch_entries": [],
+                "merged_pr_count": 0,
+            },
+        ).start()
+        res = gitea_reconcile_merged_cleanups(dry_run=True, remote="prgs", limit=10)
+        self.assertTrue(res.get("success"))
+        self.assertEqual(res.get("selection_mode"), "batch")
+        self.assertIsNone(res.get("selected_pr_number"))


 if __name__ == "__main__":
@@ -0,0 +1,244 @@
+"""#855 AC4: an expired reviewer lease must not indefinitely protect an
+already-merged branch when no live claimant exists.
+
+Two layers are covered:
+
+* ``branch_cleanup_guard.assess_expired_reviewer_lease_reclaim`` — the pure,
+  fail-closed reclaim decision. Every condition must be provably satisfied or
+  the lease keeps protecting the branch.
+* ``gitea_mcp_server._collect_branch_ownership_records`` — the wiring that
+  supplies authoritative evidence (PR merged state, owner-process liveness,
+  competing ownership) to that decision, and flips an expired reviewer lease
+  to reclaimable only under the full policy.
+
+All inputs are fabricated; no real repository, lease, or credential is used.
+"""
+
+import importlib
+import unittest
+from unittest.mock import patch
+
+import branch_cleanup_guard
+
+mcp_server = importlib.import_module("gitea_mcp_server")
+
+FAKE_AUTH = "token fake"
+REMOTE = "prgs"
+ORG = "Scaled-Tech-Consulting"
+REPO = "Gitea-Tools"
+HOST = "gitea.prgs.cc"
+BRANCH = "feat/issue-638-webui-app-shell-phase1"
+PR_NUMBER = 818
+
+
+class TestAssessExpiredReviewerLeaseReclaim(unittest.TestCase):
+    """Pure fail-closed reclaim decision (#855 AC4)."""
+
+    def _call(self, **overrides):
+        base = dict(
+            role="reviewer",
+            status="expired",
+            pr_merged=True,
+            owner_pid_alive=False,
+            competing_active_claimant=False,
+        )
+        base.update(overrides)
+        return branch_cleanup_guard.assess_expired_reviewer_lease_reclaim(**base)
+
+    def test_full_policy_satisfied_allows_reclaim(self):
+        out = self._call()
+        self.assertTrue(out["reclaim_allowed"])
+        self.assertEqual(out["reasons"], [])
+        self.assertEqual(out["decision"], "reclaim_expired_reviewer_lease")
+
+    def test_stale_dead_process_reviewer_also_reclaimable(self):
+        out = self._call(status="stale_dead_process")
+        self.assertTrue(out["reclaim_allowed"])
+
+    def test_non_reviewer_role_never_reclaims(self):
+        for role in ("author", "merger", "controller", "reconciler", "unknown"):
+            with self.subTest(role=role):
+                out = self._call(role=role)
+                self.assertFalse(out["reclaim_allowed"])
+                self.assertTrue(out["reasons"])
+                self.assertEqual(out["decision"], "keep_protecting")
+
+    def test_active_status_never_reclaims(self):
+        out = self._call(status="active")
+        self.assertFalse(out["reclaim_allowed"])
+
+    def test_pr_not_merged_blocks_reclaim(self):
+        out = self._call(pr_merged=False)
+        self.assertFalse(out["reclaim_allowed"])
+
+    def test_pr_merged_unknown_fails_closed(self):
+        out = self._call(pr_merged=None)
+        self.assertFalse(out["reclaim_allowed"])
+
+    def test_owner_process_alive_blocks_reclaim(self):
+        out = self._call(owner_pid_alive=True)
+        self.assertFalse(out["reclaim_allowed"])
+
+    def test_owner_liveness_unknown_fails_closed(self):
+        out = self._call(owner_pid_alive=None)
+        self.assertFalse(out["reclaim_allowed"])
+
+    def test_competing_active_claimant_blocks_reclaim(self):
+        out = self._call(competing_active_claimant=True)
+        self.assertFalse(out["reclaim_allowed"])
+
+    def test_competing_claimant_unknown_fails_closed(self):
+        out = self._call(competing_active_claimant=None)
+        self.assertFalse(out["reclaim_allowed"])
+
+    def test_reasons_never_leak_secrets(self):
+        out = self._call(role="author")
+        blob = " ".join(out["reasons"]).lower()
+        self.assertNotIn("token", blob)
+        self.assertNotIn("password", blob)
+
+
+class _FakeLease(dict):
+    pass
+
+
+class TestCollectorExpiredReviewerReclaimWiring(unittest.TestCase):
+    """`_collect_branch_ownership_records` supplies authoritative evidence and
+    flips an expired reviewer lease to reclaimable only under the full policy."""
+
+    def _run(
+        self,
+        *,
+        lease_role="reviewer",
+        lease_freshness="stale_dead_process",
+        owner_pid_alive=False,
+        pr_merged=True,
+        extra_leases=None,
+        worktree_on_branch=False,
+    ):
+        lease = _FakeLease(
+            role=lease_role,
+            work_kind="pr",
+            work_number=PR_NUMBER,
+            branch=BRANCH,
+            status="active",
+            owner_pid=999999,
+            remote=REMOTE,
+            org=ORG,
+            repo=REPO,
+            host=HOST,
+            freshness={
+                "freshness": lease_freshness,
+                "owner_pid": 999999,
+                "owner_pid_alive": owner_pid_alive,
+                "expired_by_time": lease_freshness == "expired",
+            },
+        )
+        leases = [lease] + list(extra_leases or [])
+
+        pr_payload = {
+            "number": PR_NUMBER,
+            "merged": pr_merged,
+            "merged_at": "2026-07-23T00:00:00Z" if pr_merged else None,
+            "head": {"ref": BRANCH},
+        }
+
+        def fake_api_request(method, url, *a, **k):
+            if method == "GET" and f"/pulls/{PR_NUMBER}" in url:
+                return pr_payload
+            raise AssertionError(f"unexpected api_request {method} {url}")
+
+        wt_entries = []
+        if worktree_on_branch:
+            wt_entries = [{"branch": BRANCH, "path": f"/x/branches/{BRANCH}"}]
+
+        with patch.object(
+            mcp_server.lease_lifecycle,
+            "list_active_leases",
+            return_value={"leases": leases},
+        ), patch.object(
+            mcp_server.control_plane_db, "get_db", return_value=object(), create=True
+        ), patch.object(
+            mcp_server.issue_lock_store, "iter_lock_files", return_value=[]
+        ), patch.object(
+            mcp_server.worktree_cleanup_audit,
+            "list_worktrees",
+            return_value=wt_entries,
+        ), patch.object(
+            mcp_server, "api_get_all", return_value=[]
+        ), patch.object(
+            mcp_server, "api_request", side_effect=fake_api_request
+        ):
+            return mcp_server._collect_branch_ownership_records(
+                remote=REMOTE,
+                host=HOST,
+                org=ORG,
+                repo=REPO,
+                branch=BRANCH,
+                pr_number=PR_NUMBER,
+                project_root="/x",
+                auth=FAKE_AUTH,
+                base_api="https://gitea.prgs.cc/api/v1/repos/x/y",
+            )
+
+    def _reviewer_records(self, bundle):
+        return [
+            rec
+            for rec in bundle["records"]
+            if rec.get("category")
+            == branch_cleanup_guard.OWNERSHIP_CATEGORY_REVIEWER_LEASE
+        ]
+
+    def test_merged_dead_uncontested_reviewer_lease_is_reclaimable(self):
+        bundle = self._run()
+        self.assertFalse(bundle["inventory_error"])
+        recs = self._reviewer_records(bundle)
+        self.assertEqual(len(recs), 1)
+        self.assertTrue(recs[0]["reclaim_allowed"])
+        # And the guard consequently does not block deletion on it.
+        ownership = branch_cleanup_guard.assess_active_branch_ownership(
+            remote=REMOTE, org=ORG, repo=REPO, branch=BRANCH, host=HOST,
+            records=bundle["records"],
+        )
+        self.assertFalse(ownership["block"])
+
+    def test_unmerged_pr_keeps_reviewer_lease_protective(self):
+        bundle = self._run(pr_merged=False)
+        recs = self._reviewer_records(bundle)
+        self.assertEqual(len(recs), 1)
+        self.assertFalse(recs[0]["reclaim_allowed"])
+        ownership = branch_cleanup_guard.assess_active_branch_ownership(
+            remote=REMOTE, org=ORG, repo=REPO, branch=BRANCH, host=HOST,
+            records=bundle["records"],
+        )
+        self.assertTrue(ownership["block"])
+
+    def test_owner_process_alive_keeps_reviewer_lease_protective(self):
+        bundle = self._run(owner_pid_alive=True, lease_freshness="expired")
+        recs = self._reviewer_records(bundle)
+        self.assertFalse(recs[0]["reclaim_allowed"])
+
+    def test_competing_worktree_binding_keeps_reviewer_lease_protective(self):
+        bundle = self._run(worktree_on_branch=True)
+        recs = self._reviewer_records(bundle)
+        self.assertFalse(recs[0]["reclaim_allowed"])
+        ownership = branch_cleanup_guard.assess_active_branch_ownership(
+            remote=REMOTE, org=ORG, repo=REPO, branch=BRANCH, host=HOST,
+            records=bundle["records"],
+        )
+        self.assertTrue(ownership["block"])
+
+    def test_expired_author_lease_never_reclaimed_by_reviewer_policy(self):
+        bundle = self._run(lease_role="author")
+        author_recs = [
+            rec
+            for rec in bundle["records"]
+            if rec.get("category")
+            == branch_cleanup_guard.OWNERSHIP_CATEGORY_AUTHOR_LEASE
+        ]
+        self.assertEqual(len(author_recs), 1)
+        self.assertFalse(author_recs[0]["reclaim_allowed"])
+
+
+if __name__ == "__main__":
+    unittest.main()
@@ -0,0 +1,551 @@
+"""Merged-PR awareness for the worktree cleanup audit (#858).
+
+Before #858 an ``issue_work`` worktree could never leave ``active_issue_work``:
+the audit had no PR linkage at all (``pr_number`` was structurally ``None``)
+and its only route to ``clean_stale_removable`` was a TTL derived from a
+``last_used_at`` that nothing ever populated. A merged, clean, unprotected
+worktree was therefore reported as active work forever, disagreeing with the
+PR-scoped reconciler.
+
+These tests use fabricated temporary repositories and synthetic PR records
+only. Nothing here removes a worktree or deletes a branch.
+"""
+
+import os
+import subprocess
+import sys
+import tempfile
+import unittest
+from unittest.mock import patch
+
+sys.path.insert(0, str(__import__("pathlib").Path(__file__).resolve().parent.parent))
+
+import merged_cleanup_reconcile as mcr  # noqa: E402
+import worktree_cleanup_audit as wca  # noqa: E402
+
+
+MERGED_BRANCH = "feat/issue-777-timeline"
+MERGED_PATH = "/repo/branches/issue-777-timeline"
+HEAD_SHA = "a" * 40
+
+
+def _pr(number, branch, *, merged=True, sha=HEAD_SHA, state=None):
+    """Synthetic Gitea PR payload."""
+    return {
+        "number": number,
+        "head": {"ref": branch, "sha": sha},
+        "merged_at": "2026-07-24T01:00:00Z" if merged else None,
+        "state": state or ("closed" if merged else "open"),
+    }
+
+
+def _porcelain(*entries):
+    out = []
+    for path, branch, sha in entries:
+        out.append(f"worktree {path}")
+        out.append(f"HEAD {sha}")
+        if branch is None:
+            out.append("detached")
+        else:
+            out.append(f"branch refs/heads/{branch}")
+        out.append("")
+    return "\n".join(out)
+
+
+class _AuditHarness(unittest.TestCase):
+    """Runs audit_branches_directory over a fabricated worktree listing."""
+
+    PORCELAIN = _porcelain(
+        ("/repo", "master", "f" * 40),
+        (MERGED_PATH, MERGED_BRANCH, HEAD_SHA),
+    )
+
+    def run_audit(self, *, dirty_paths=(), contained=True, **kwargs):
+        def fake_dirty(path):
+            if path in dirty_paths:
+                return {"exists": True, "dirty": True, "dirty_files": [" M x.py"]}
+            return {"exists": True, "dirty": False, "dirty_files": []}
+
+        with patch.object(
+            wca, "list_worktrees",
+            return_value=wca.parse_worktree_porcelain(self.PORCELAIN),
+        ), patch.object(
+            wca, "read_worktree_dirty", side_effect=fake_dirty
+        ), patch.object(
+            wca, "git_worktree_list", return_value="(mocked)"
+        ), patch.object(
+            wca, "is_head_ancestor_of_ref", return_value=contained
+        ):
+            report = wca.audit_branches_directory("/repo", **kwargs)
+        return {wt["path"]: wt for wt in report["worktrees"]}, report
+
+    def merged_audit(self, **kwargs):
+        kwargs.setdefault("pr_index", wca.build_pr_index([_pr(849, MERGED_BRANCH)]))
+        kwargs.setdefault("master_ref", "prgs/master")
+        return self.run_audit(**kwargs)
+
+
+class TestMergedWorktreeBecomesRemovable(_AuditHarness):
+    def test_clean_merged_issue_worktree_is_linked_and_removable(self):
+        by_path, report = self.merged_audit()
+        entry = by_path[MERGED_PATH]
+
+        self.assertEqual(entry["classification"], wca.CLASS_CLEAN_STALE_REMOVABLE)
+        self.assertTrue(entry["removable"])
+        self.assertEqual(entry["merged_pr_linkage"]["status"], wca.LINKAGE_MERGED)
+        self.assertEqual(entry["merged_pr_cleanup"]["block_reasons"], [])
+        self.assertIn(MERGED_PATH, [c["path"] for c in report["removable_candidates"]])
+
+    def test_pr_number_populated_from_authoritative_linkage(self):
+        by_path, _ = self.merged_audit()
+        self.assertEqual(by_path[MERGED_PATH]["pr_number"], 849)
+
+    def test_regression_without_pr_evidence_stays_active_issue_work(self):
+        """The pre-#858 behaviour, still correct when no PR state is supplied."""
+        by_path, _ = self.run_audit()
+        entry = by_path[MERGED_PATH]
+        self.assertEqual(entry["classification"], wca.CLASS_ACTIVE_ISSUE_WORK)
+        self.assertFalse(entry["removable"])
+        self.assertIsNone(entry["pr_number"])
+
+
+class TestProtectiveSignalsSurvive(_AuditHarness):
+    def test_open_pr_worktree_is_not_removable(self):
+        index = wca.build_pr_index([_pr(900, MERGED_BRANCH, merged=False)])
+        by_path, _ = self.run_audit(
+            pr_index=index,
+            master_ref="prgs/master",
+            open_pr_branches={MERGED_BRANCH},
+        )
+        entry = by_path[MERGED_PATH]
+        self.assertEqual(entry["classification"], wca.CLASS_ACTIVE_OPEN_PR)
+        self.assertFalse(entry["removable"])
+        # linkage still reports the owning PR, it just is not merge proof
+        self.assertEqual(entry["merged_pr_linkage"]["status"], wca.LINKAGE_OPEN)
+        self.assertEqual(entry["pr_number"], 900)
+
+    def test_dirty_tracked_worktree_is_not_removable(self):
+        by_path, _ = self.merged_audit(dirty_paths=(MERGED_PATH,))
+        entry = by_path[MERGED_PATH]
+        self.assertEqual(entry["classification"], wca.CLASS_DIRTY_LOCAL)
+        self.assertFalse(entry["removable"])
+        self.assertIn(
+            "worktree has uncommitted changes",
+            entry["merged_pr_cleanup"]["block_reasons"],
+        )
+
+    def test_untracked_only_worktree_is_not_removable(self):
+        """``git status --porcelain`` reports untracked files as dirty too."""
+        def untracked(path):
+            if path == MERGED_PATH:
+                return {"exists": True, "dirty": True, "dirty_files": ["?? scratch.txt"]}
+            return {"exists": True, "dirty": False, "dirty_files": []}
+
+        with patch.object(
+            wca, "list_worktrees",
+            return_value=wca.parse_worktree_porcelain(self.PORCELAIN),
+        ), patch.object(
+            wca, "read_worktree_dirty", side_effect=untracked
+        ), patch.object(
+            wca, "git_worktree_list", return_value="(mocked)"
+        ), patch.object(
+            wca, "is_head_ancestor_of_ref", return_value=True
+        ):
+            report = wca.audit_branches_directory(
+                "/repo",
+                pr_index=wca.build_pr_index([_pr(849, MERGED_BRANCH)]),
+                master_ref="prgs/master",
+            )
+        entry = {wt["path"]: wt for wt in report["worktrees"]}[MERGED_PATH]
+        self.assertEqual(entry["classification"], wca.CLASS_DIRTY_LOCAL)
+        self.assertFalse(entry["removable"])
+
+    def test_active_lease_by_issue_number_is_protective(self):
+        by_path, _ = self.merged_audit(leased_issue_numbers={777})
+        entry = by_path[MERGED_PATH]
+        self.assertTrue(entry["has_active_lease"])
+        self.assertEqual(entry["classification"], wca.CLASS_ACTIVE_ISSUE_WORK)
+        self.assertFalse(entry["removable"])
+
+    def test_active_lease_by_branch_is_protective(self):
+        by_path, _ = self.merged_audit(leased_branches={MERGED_BRANCH})
+        entry = by_path[MERGED_PATH]
+        self.assertTrue(entry["has_active_lease"])
+        self.assertFalse(entry["removable"])
+
+    def test_active_issue_lock_is_protective(self):
+        by_path, _ = self.merged_audit(active_issue_branches={MERGED_BRANCH})
+        entry = by_path[MERGED_PATH]
+        self.assertTrue(entry["has_active_issue_lock"])
+        self.assertEqual(entry["classification"], wca.CLASS_ACTIVE_ISSUE_WORK)
+        self.assertFalse(entry["removable"])
+
+    def test_live_session_worktree_is_protective(self):
+        by_path, _ = self.merged_audit(live_session_paths={MERGED_PATH})
+        entry = by_path[MERGED_PATH]
+        self.assertTrue(entry["has_live_session"])
+        self.assertEqual(entry["classification"], wca.CLASS_ACTIVE_ISSUE_WORK)
+        self.assertFalse(entry["removable"])
+
+    def test_head_not_contained_in_master_is_not_removable(self):
+        by_path, _ = self.merged_audit(contained=False)
+        entry = by_path[MERGED_PATH]
+        self.assertEqual(entry["classification"], wca.CLASS_ACTIVE_ISSUE_WORK)
+        self.assertFalse(entry["removable"])
+        self.assertIn(
+            "worktree head is not contained in authoritative master "
+            "(unmerged commits remain)",
+            entry["merged_pr_cleanup"]["block_reasons"],
+        )
+
+    def test_unknown_containment_fails_closed(self):
+        by_path, _ = self.merged_audit(contained=None)
+        entry = by_path[MERGED_PATH]
+        self.assertFalse(entry["removable"])
+        self.assertIn(
+            "containment of the worktree head in master is unknown",
+            entry["merged_pr_cleanup"]["block_reasons"],
+        )
+
+    def test_missing_master_ref_fails_closed(self):
+        by_path, _ = self.run_audit(
+            pr_index=wca.build_pr_index([_pr(849, MERGED_BRANCH)])
+        )
+        self.assertFalse(by_path[MERGED_PATH]["removable"])
+
+    def test_unmerged_owning_pr_is_not_removable(self):
+        index = wca.build_pr_index([_pr(901, MERGED_BRANCH, merged=False)])
+        by_path, _ = self.run_audit(pr_index=index, master_ref="prgs/master")
+        entry = by_path[MERGED_PATH]
+        self.assertFalse(entry["removable"])
+        self.assertIn(
+            "owning PR #901 is not merged",
+            entry["merged_pr_cleanup"]["block_reasons"],
+        )
+
+    def test_control_checkout_is_never_removable(self):
+        by_path, _ = self.merged_audit()
+        control = by_path["/repo"]
+        self.assertTrue(control["is_protected"])
+        self.assertEqual(control["classification"], wca.CLASS_UNSAFE_UNKNOWN)
+        self.assertFalse(control["removable"])
+
+    def test_control_checkout_not_removable_even_if_linked_and_merged(self):
+        """A merged PR on the control checkout must not unlock removal."""
+        porcelain = _porcelain(("/repo", MERGED_BRANCH, HEAD_SHA))
+        with patch.object(
+            wca, "list_worktrees", return_value=wca.parse_worktree_porcelain(porcelain)
+        ), patch.object(
+            wca, "read_worktree_dirty",
+            return_value={"exists": True, "dirty": False, "dirty_files": []},
+        ), patch.object(
+            wca, "git_worktree_list", return_value="(mocked)"
+        ), patch.object(
+            wca, "is_head_ancestor_of_ref", return_value=True
+        ):
+            report = wca.audit_branches_directory(
+                "/repo",
+                pr_index=wca.build_pr_index([_pr(849, MERGED_BRANCH)]),
+                master_ref="prgs/master",
+            )
+        entry = report["worktrees"][0]
+        self.assertEqual(entry["classification"], wca.CLASS_UNSAFE_UNKNOWN)
+        self.assertFalse(entry["removable"])
+
+
+class TestAmbiguousLinkageFailsClosed(_AuditHarness):
+    def test_competing_prs_on_one_branch_fail_closed(self):
+        index = wca.build_pr_index(
+            [_pr(849, MERGED_BRANCH), _pr(860, MERGED_BRANCH)]
+        )
+        by_path, _ = self.run_audit(pr_index=index, master_ref="prgs/master")
+        entry = by_path[MERGED_PATH]
+        self.assertEqual(entry["merged_pr_linkage"]["status"], wca.LINKAGE_AMBIGUOUS)
+        self.assertIsNone(entry["pr_number"])
+        self.assertEqual(entry["classification"], wca.CLASS_ACTIVE_ISSUE_WORK)
+        self.assertFalse(entry["removable"])
+
+    def test_merged_plus_open_pr_on_one_branch_fails_closed(self):
+        index = wca.build_pr_index(
+            [_pr(849, MERGED_BRANCH), _pr(861, MERGED_BRANCH, merged=False)]
+        )
+        by_path, _ = self.run_audit(pr_index=index, master_ref="prgs/master")
+        entry = by_path[MERGED_PATH]
+        self.assertEqual(entry["merged_pr_linkage"]["status"], wca.LINKAGE_AMBIGUOUS)
+        self.assertFalse(entry["removable"])
+
+    def test_no_owning_pr_fails_closed(self):
+        by_path, _ = self.run_audit(
+            pr_index=wca.build_pr_index([_pr(849, "feat/other-branch")]),
+            master_ref="prgs/master",
+        )
+        entry = by_path[MERGED_PATH]
+        self.assertEqual(entry["merged_pr_linkage"]["status"], wca.LINKAGE_NONE)
+        self.assertFalse(entry["removable"])
+
+    def test_malformed_pr_records_are_dropped_not_guessed(self):
+        index = wca.build_pr_index(
+            [
+                {"number": None, "head": {"ref": MERGED_BRANCH}},
+                {"number": 5, "head": {}},
+                {"number": "not-an-int", "head": {"ref": MERGED_BRANCH}},
+            ]
+        )
+        self.assertEqual(index, {})
+        self.assertEqual(
+            wca.resolve_owning_pr(branch=MERGED_BRANCH, pr_index=index)["status"],
+            wca.LINKAGE_NONE,
+        )
+
+    def test_detached_worktree_has_no_branch_linkage(self):
+        self.assertEqual(
+            wca.resolve_owning_pr(branch=None, pr_index={})["status"],
+            wca.LINKAGE_UNKNOWN,
+        )
+
+
+class TestUnrelatedClassificationsUnchanged(unittest.TestCase):
+    """Non-issue_work worktrees keep their pre-#858 classifications."""
+
+    PORCELAIN = _porcelain(
+        ("/repo", "master", "f" * 40),
+        ("/repo/branches/review-pr42", "review-pr42", "2" * 40),
+        ("/repo/branches/baseline-master-x", "baseline-master-x", "3" * 40),
+        ("/repo/branches/conflict-fix-pr50", "conflict-fix-pr50", "4" * 40),
+        ("/repo/branches/review-pr99", None, "5" * 40),
+    )
+
+    def _audit(self, **kwargs):
+        with patch.object(
+            wca, "list_worktrees",
+            return_value=wca.parse_worktree_porcelain(self.PORCELAIN),
+        ), patch.object(
+            wca, "read_worktree_dirty",
+            return_value={"exists": True, "dirty": False, "dirty_files": []},
+        ), patch.object(
+            wca, "git_worktree_list", return_value="(mocked)"
+        ), patch.object(
+            wca, "is_head_ancestor_of_ref", return_value=True
+        ):
+            report = wca.audit_branches_directory("/repo", **kwargs)
+        return {wt["path"]: wt for wt in report["worktrees"]}
+
+    def test_classifications_identical_with_and_without_pr_evidence(self):
+        without = self._audit()
+        with_evidence = self._audit(
+            pr_index=wca.build_pr_index([_pr(849, MERGED_BRANCH)]),
+            master_ref="prgs/master",
+        )
+        self.assertEqual(
+            {p: e["classification"] for p, e in without.items()},
+            {p: e["classification"] for p, e in with_evidence.items()},
+        )
+
+    def test_lease_on_issue_does_not_capture_similarly_named_scratch_trees(self):
+        """A lease on issue 777 protects issue work, not baseline/review trees."""
+        porcelain = _porcelain(
+            ("/repo/branches/baseline-master-issue-777", "baseline-issue-777", "7" * 40),
+            ("/repo/branches/issue-777-timeline", MERGED_BRANCH, HEAD_SHA),
+        )
+        with patch.object(
+            wca, "list_worktrees", return_value=wca.parse_worktree_porcelain(porcelain)
+        ), patch.object(
+            wca, "read_worktree_dirty",
+            return_value={"exists": True, "dirty": False, "dirty_files": []},
+        ), patch.object(
+            wca, "git_worktree_list", return_value="(mocked)"
+        ), patch.object(
+            wca, "is_head_ancestor_of_ref", return_value=True
+        ):
+            report = wca.audit_branches_directory(
+                "/repo",
+                pr_index=wca.build_pr_index([_pr(849, MERGED_BRANCH)]),
+                master_ref="prgs/master",
+                leased_issue_numbers={777},
+            )
+        by_path = {wt["path"]: wt for wt in report["worktrees"]}
+
+        baseline = by_path["/repo/branches/baseline-master-issue-777"]
+        self.assertFalse(baseline["has_active_lease"])
+        self.assertEqual(baseline["classification"], wca.CLASS_CLEAN_STALE_REMOVABLE)
+
+        issue_work = by_path["/repo/branches/issue-777-timeline"]
+        self.assertTrue(issue_work["has_active_lease"])
+        self.assertFalse(issue_work["removable"])
+
+    def test_review_and_baseline_still_removable(self):
+        by_path = self._audit(
+            pr_index=wca.build_pr_index([]), master_ref="prgs/master"
+        )
+        self.assertEqual(
+            by_path["/repo/branches/review-pr42"]["classification"],
+            wca.CLASS_CLEAN_STALE_REMOVABLE,
+        )
+        self.assertEqual(
+            by_path["/repo/branches/baseline-master-x"]["classification"],
+            wca.CLASS_CLEAN_STALE_REMOVABLE,
+        )
+        self.assertEqual(
+            by_path["/repo/branches/review-pr99"]["classification"],
+            wca.CLASS_DETACHED_REVIEW_LEFTOVER,
+        )
+
+    def test_conflict_fix_ttl_behaviour_unchanged(self):
+        """conflict_fix still needs only TTL expiry; #858 did not touch it."""
+        self.assertEqual(
+            wca.classify_worktree(
+                workflow_type=wca.WORKFLOW_CONFLICT_FIX,
+                is_dirty=False,
+                ttl_expired=True,
+            ),
+            wca.CLASS_CLEAN_STALE_REMOVABLE,
+        )
+        self.assertEqual(
+            wca.classify_worktree(
+                workflow_type=wca.WORKFLOW_CONFLICT_FIX,
+                is_dirty=False,
+                ttl_expired=False,
+            ),
+            wca.CLASS_ACTIVE_ISSUE_WORK,
+        )
+
+    def test_issue_work_ttl_alone_no_longer_grants_removal(self):
+        """Age is not landing proof: TTL alone must not reclaim issue work."""
+        self.assertEqual(
+            wca.classify_worktree(
+                workflow_type=wca.WORKFLOW_ISSUE_WORK,
+                is_dirty=False,
+                ttl_expired=True,
+            ),
+            wca.CLASS_ACTIVE_ISSUE_WORK,
+        )
+
+
+class TestAssessorPerformsNoDeletion(_AuditHarness):
+    def test_audit_never_removes_a_worktree(self):
+        with patch.object(wca, "remove_worktree") as removal:
+            self.merged_audit()
+        removal.assert_not_called()
+
+    def test_audit_shells_out_to_no_destructive_git_command(self):
+        seen = []
+        real_run = subprocess.run
+
+        def recording_run(cmd, *args, **kwargs):
+            seen.append(cmd)
+            return real_run(["true"], *args, **kwargs)
+
+        with patch.object(subprocess, "run", side_effect=recording_run):
+            wca.audit_branches_directory("/nonexistent-repo-for-audit")
+
+        joined = [" ".join(c) if isinstance(c, list) else str(c) for c in seen]
+        for cmd in joined:
+            self.assertNotIn("worktree remove", cmd)
+            self.assertNotIn("branch -D", cmd)
+            self.assertNotIn("push", cmd)
+
+
+class TestAgreementWithPrScopedReconciler(unittest.TestCase):
+    """The audit and merged_cleanup_reconcile must agree on identical input.
+
+    Uses a real throwaway git repository so containment is computed by git
+    rather than asserted. Nothing outside the temporary directory is touched.
+    """
+
+    def _git(self, *args):
+        subprocess.run(
+            ["git", "-C", self.root, *args],
+            check=True,
+            capture_output=True,
+            text=True,
+        )
+
+    def setUp(self):
+        self._tmp = tempfile.TemporaryDirectory()
+        self.root = os.path.realpath(self._tmp.name)
+        self._git("init", "-b", "master", ".")
+        self._git("config", "user.email", "[email protected]")
+        self._git("config", "user.name", "Test")
+        with open(os.path.join(self.root, "seed.txt"), "w") as fh:
+            fh.write("seed\n")
+        self._git("add", "seed.txt")
+        self._git("commit", "-m", "seed")
+
+        self.branch = "feat/issue-777-timeline"
+        self._git("checkout", "-b", self.branch)
+        with open(os.path.join(self.root, "feature.txt"), "w") as fh:
+            fh.write("feature\n")
+        self._git("add", "feature.txt")
+        self._git("commit", "-m", "feature")
+        self.head_sha = subprocess.run(
+            ["git", "-C", self.root, "rev-parse", "HEAD"],
+            capture_output=True, text=True, check=True,
+        ).stdout.strip()
+        self._git("checkout", "master")
+        self._git("merge", "--no-ff", "-m", "merge feature", self.branch)
+
+        self.worktree = os.path.join(self.root, "branches", "issue-777-timeline")
+        self._git("worktree", "add", self.worktree, self.branch)
+
+    def tearDown(self):
+        self._tmp.cleanup()
+
+    def _pr_index(self):
+        return wca.build_pr_index(
+            [
+                {
+                    "number": 849,
+                    "head": {"ref": self.branch, "sha": self.head_sha},
+                    "merged_at": "2026-07-24T01:00:00Z",
+                }
+            ]
+        )
+
+    def _audit_entry(self):
+        report = wca.audit_branches_directory(
+            self.root, pr_index=self._pr_index(), master_ref="master"
+        )
+        return next(wt for wt in report["worktrees"] if wt["path"] == self.worktree)
+
+    def _reconciler_entry(self):
+        return mcr.assess_local_worktree_cleanup(
+            pr_number=849,
+            head_branch=self.branch,
+            merged=True,
+            worktree_state=mcr.resolve_cleanup_worktree_state(
+                project_root=self.root,
+                head_branch=self.branch,
+                issue_number=777,
+                pr_head_sha=self.head_sha,
+                target_ref="master",
+            ),
+            active_lock=False,
+        )
+
+    def test_both_assessors_agree_the_worktree_is_safe(self):
+        audit_entry = self._audit_entry()
+        reconciler = self._reconciler_entry()
+
+        self.assertTrue(reconciler["safe_to_remove_worktree"], reconciler)
+        self.assertTrue(audit_entry["removable"], audit_entry)
+        self.assertEqual(audit_entry["pr_number"], reconciler["pr_number"])
+        self.assertEqual(audit_entry["merged_pr_cleanup"]["block_reasons"], [])
+        self.assertEqual(reconciler["block_reasons"], [])
+
+    def test_both_assessors_agree_a_dirty_worktree_is_unsafe(self):
+        with open(os.path.join(self.worktree, "feature.txt"), "a") as fh:
+            fh.write("local edit\n")
+
+        audit_entry = self._audit_entry()
+        reconciler = self._reconciler_entry()
+
+        self.assertFalse(audit_entry["removable"])
+        self.assertFalse(reconciler["safe_to_remove_worktree"])
+
+    def test_worktree_still_present_after_audit(self):
+        self._audit_entry()
+        self.assertTrue(os.path.isdir(self.worktree))
+
+
+if __name__ == "__main__":
+    unittest.main()
@@ -0,0 +1,630 @@
+"""Durable linked-issue lock head refresh + merge-sync dead-session recovery (#871).
+
+``gitea_update_pr_branch_by_merge`` advances a PR's *remote* head but historically
+never advanced the linked durable issue lock's recorded head. After the owning
+session died the drifted lock became unrecoverable and no further synchronization
+was possible (PR #866 / issue #855).
+
+Two halves are covered:
+
+* the write-side refresh (``issue_lock_store.assess/apply_durable_lock_head_refresh``)
+  that records the new synced head under compare-and-swap with read-after-write; and
+* the read-side recovery relation (``issue_lock_recovery`` +
+  ``issue_lock_worktree.read_merge_sync_provenance``) that lets a dead-session lock
+  whose recorded head is a merge-sync *ancestor* of the live PR head be recovered —
+  and nothing else.
+"""
+
+from __future__ import annotations
+
+import os
+import subprocess
+import sys
+import tempfile
+import unittest
+from datetime import datetime, timedelta, timezone
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+import issue_lock_recovery  # noqa: E402
+import issue_lock_store  # noqa: E402
+import issue_lock_worktree  # noqa: E402
+
+ISSUE = 8710
+PR_NUMBER = 8711
+BRANCH = f"fix/issue-{ISSUE}-durable-lock-head-refresh"
+IDENTITY = "example-user"
+PROFILE = "example-author"
+OLD = "a" * 40
+NEW1 = "b" * 40
+NEW2 = "c" * 40
+BASE = "d" * 40
+REMOTE = "prgs"
+ORG = "ExampleOrg"
+REPO = "ExampleRepo"
+
+
+def dead_pid() -> int:
+    proc = subprocess.Popen([sys.executable, "-c", "pass"])
+    proc.wait()
+    return proc.pid
+
+
+def future_ts(hours: int = 4) -> str:
+    return (
+        (datetime.now(timezone.utc) + timedelta(hours=hours))
+        .isoformat()
+        .replace("+00:00", "Z")
+    )
+
+
+def _git(cwd, *args):
+    return subprocess.run(
+        ["git", "-C", cwd, *args],
+        capture_output=True,
+        text=True,
+        check=True,
+    )
+
+
+def _rev(cwd, ref="HEAD") -> str:
+    return _git(cwd, "rev-parse", ref).stdout.strip()
+
+
+def build_merge_sync_repo(tmp: str) -> dict:
+    """Build a repo where a feature branch was synced by merging master in.
+
+    Returns a dict with the prior (branch) head, the synced merge-commit head,
+    the master tip, plus a rebase-style linear descendant and an unrelated head.
+    """
+    _git(tmp, "init", "-q", "-b", "master")
+    _git(tmp, "config", "user.email", "[email protected]")
+    _git(tmp, "config", "user.name", "T")
+    Path(tmp, "base.txt").write_text("base\n")
+    _git(tmp, "add", "-A")
+    _git(tmp, "commit", "-q", "-m", "root")
+
+    # Feature branch cut from root, one commit — this is the PRIOR/recorded head.
+    _git(tmp, "checkout", "-q", "-b", BRANCH)
+    Path(tmp, "feature.txt").write_text("feature\n")
+    _git(tmp, "add", "-A")
+    _git(tmp, "commit", "-q", "-m", "feature work")
+    prior = _rev(tmp)
+
+    # Master advances (the base the sync will merge in).
+    _git(tmp, "checkout", "-q", "master")
+    Path(tmp, "base.txt").write_text("base\nmore\n")
+    _git(tmp, "add", "-A")
+    _git(tmp, "commit", "-q", "-m", "master advance")
+    master_tip = _rev(tmp)
+
+    # Sync: merge master INTO the feature branch → merge commit, first parent = prior.
+    _git(tmp, "checkout", "-q", BRANCH)
+    _git(tmp, "merge", "-q", "--no-ff", "-m", "Merge master into feature", "master")
+    synced = _rev(tmp)
+
+    # A plain linear descendant of prior (NOT a merge) — a rebase/extra-commit shape.
+    _git(tmp, "checkout", "-q", "-b", "linear-branch", prior)
+    Path(tmp, "extra.txt").write_text("extra\n")
+    _git(tmp, "add", "-A")
+    _git(tmp, "commit", "-q", "-m", "extra linear commit")
+    linear = _rev(tmp)
+
+    # An unrelated root (force-push / rewritten history shape).
+    unrelated_dir = tempfile.mkdtemp()
+    _git(unrelated_dir, "init", "-q", "-b", "x")
+    _git(unrelated_dir, "config", "user.email", "[email protected]")
+    _git(unrelated_dir, "config", "user.name", "T")
+    Path(unrelated_dir, "z.txt").write_text("z\n")
+    _git(unrelated_dir, "add", "-A")
+    _git(unrelated_dir, "commit", "-q", "-m", "unrelated")
+    unrelated = _rev(unrelated_dir)
+
+    # Leave the worktree checked out on the feature branch at the PRIOR head, as
+    # a dead author session that never advanced would have left it.
+    _git(tmp, "checkout", "-q", BRANCH)
+    _git(tmp, "reset", "-q", "--hard", prior)
+
+    return {
+        "prior": prior,
+        "master_tip": master_tip,
+        "synced": synced,
+        "linear": linear,
+        "unrelated": unrelated,
+    }
+
+
+# ─────────────────────────── write-side refresh ───────────────────────────
+
+
+class TestDurableLockHeadRefresh(unittest.TestCase):
+    def setUp(self):
+        self.lock_dir = tempfile.mkdtemp()
+        self.wt = tempfile.mkdtemp()
+        lock_data = {
+            "issue_number": ISSUE,
+            "branch_name": BRANCH,
+            "worktree_path": self.wt,
+            "remote": REMOTE,
+            "org": ORG,
+            "repo": REPO,
+            "claimant": {"username": IDENTITY, "profile": PROFILE},
+            "work_lease": {
+                "operation_type": issue_lock_store.AUTHOR_ISSUE_WORK_LEASE,
+                "issue_number": ISSUE,
+                "branch": BRANCH,
+                "worktree_path": self.wt,
+                "claimant": {"username": IDENTITY, "profile": PROFILE},
+                "expires_at": future_ts(),
+            },
+        }
+        issue_lock_store.bind_session_lock(lock_data, lock_dir=self.lock_dir)
+
+    def _apply(self, **over):
+        kw = dict(
+            remote=REMOTE, org=ORG, repo=REPO, issue_number=ISSUE,
+            branch_name=BRANCH, worktree_path=self.wt, pr_number=PR_NUMBER,
+            identity=IDENTITY, profile=PROFILE, current_pid=os.getpid(),
+            expected_old_head=OLD, new_head=NEW1, synced_at=future_ts(0),
+            base_head=BASE, lock_dir=self.lock_dir,
+        )
+        kw.update(over)
+        return issue_lock_store.apply_durable_lock_head_refresh(**kw)
+
+    def _load(self):
+        return issue_lock_store.load_issue_lock(
+            remote=REMOTE, org=ORG, repo=REPO, issue_number=ISSUE,
+            lock_dir=self.lock_dir,
+        )
+
+    def test_first_sync_updates_recorded_head(self):
+        """AC1: first base sync writes the resulting head to the durable lock."""
+        res = self._apply()
+        self.assertTrue(res["refreshed"], res["reasons"])
+        self.assertTrue(res["read_after_write_ok"])
+        self.assertEqual(self._load().get("synced_pr_head"), NEW1)
+
+    def test_second_sync_after_master_advance(self):
+        """AC2: a later master advance permits a second sanctioned sync."""
+        self.assertTrue(self._apply()["refreshed"])
+        res2 = self._apply(expected_old_head=NEW1, new_head=NEW2)
+        self.assertTrue(res2["refreshed"], res2["reasons"])
+        self.assertEqual(self._load().get("synced_pr_head"), NEW2)
+        history = self._load().get("branch_sync_history")
+        self.assertEqual(len(history), 2)
+        self.assertEqual(history[0]["last_synced_pr_head"], NEW1)
+        self.assertEqual(history[1]["prior_pr_head"], NEW1)
+
+    def test_cas_detects_concurrent_head_change(self):
+        """AC6: CAS refuses when the recorded synced head is not the old head."""
+        self.assertTrue(self._apply()["refreshed"])  # recorded head now NEW1
+        # A second sync claiming the old head is still OLD must fail closed.
+        res = self._apply(expected_old_head=OLD, new_head=NEW2)
+        self.assertFalse(res["refreshed"])
+        self.assertTrue(any("CAS" in r or "concurrent" in r for r in res["reasons"]))
+        self.assertEqual(self._load().get("synced_pr_head"), NEW1)
+
+    def test_wrong_issue_fails_closed(self):
+        res = self._apply(issue_number=999999)
+        self.assertFalse(res["refreshed"])
+
+    def test_wrong_branch_fails_closed(self):
+        res = self._apply(branch_name="fix/issue-8710-wrong")
+        self.assertFalse(res["refreshed"])
+
+    def test_wrong_repo_fails_closed(self):
+        res = self._apply(repo="OtherRepo")
+        self.assertFalse(res["refreshed"])
+
+    def test_wrong_identity_fails_closed(self):
+        res = self._apply(identity="intruder")
+        self.assertFalse(res["refreshed"])
+
+    def test_wrong_profile_fails_closed(self):
+        res = self._apply(profile="prgs-reviewer")
+        self.assertFalse(res["refreshed"])
+
+    def test_foreign_session_fails_closed(self):
+        """A refresh is not a recovery: the current process must own the lock."""
+        path = issue_lock_store.lock_file_path(
+            remote=REMOTE, org=ORG, repo=REPO, issue_number=ISSUE,
+            lock_dir=self.lock_dir,
+        )
+        rec = issue_lock_store.read_lock_file(path)
+        rec["session_pid"] = dead_pid()
+        rec["pid"] = rec["session_pid"]
+        issue_lock_store.save_lock_file(path, rec)
+        res = self._apply()
+        self.assertFalse(res["refreshed"])
+        self.assertTrue(any("current session" in r or "live owner" in r for r in res["reasons"]))
+
+    def test_new_equals_old_fails_closed(self):
+        res = self._apply(expected_old_head=OLD, new_head=OLD)
+        self.assertFalse(res["refreshed"])
+
+    def test_non_full_sha_fails_closed(self):
+        self.assertFalse(self._apply(new_head="deadbeef")["refreshed"])
+        self.assertFalse(self._apply(expected_old_head="xyz")["refreshed"])
+
+    def test_no_lock_fails_closed(self):
+        assessment = issue_lock_store.assess_durable_lock_head_refresh(
+            None, remote=REMOTE, org=ORG, repo=REPO, issue_number=ISSUE,
+            branch_name=BRANCH, worktree_path=self.wt, pr_number=PR_NUMBER,
+            identity=IDENTITY, profile=PROFILE, current_pid=os.getpid(),
+            expected_old_head=OLD, new_head=NEW1,
+        )
+        self.assertFalse(assessment["allowed"])
+
+
+# ─────────────────────── merge-sync provenance (real git) ───────────────────
+
+
+class TestMergeSyncProvenanceObservation(unittest.TestCase):
+    def setUp(self):
+        self.tmp = tempfile.mkdtemp()
+        self.shas = build_merge_sync_repo(self.tmp)
+
+    def test_merge_sync_is_recognized(self):
+        obs = issue_lock_worktree.read_merge_sync_provenance(
+            self.tmp, prior_head_sha=self.shas["prior"],
+            synced_head_sha=self.shas["synced"],
+        )
+        self.assertTrue(obs["is_merge_sync"], obs["reasons"])
+        self.assertTrue(obs["prior_is_ancestor"])
+        self.assertTrue(obs["synced_is_merge"])
+        self.assertTrue(obs["first_parent_reaches_prior"])
+
+    def test_linear_descendant_is_not_a_merge_sync(self):
+        """A plain non-merge descendant (rebase/extra commit) is not a sync."""
+        obs = issue_lock_worktree.read_merge_sync_provenance(
+            self.tmp, prior_head_sha=self.shas["prior"],
+            synced_head_sha=self.shas["linear"],
+        )
+        self.assertTrue(obs["probe_ok"])
+        self.assertFalse(obs["is_merge_sync"])
+        self.assertFalse(obs["synced_is_merge"])
+
+    def test_unrelated_history_fails_closed(self):
+        """A rewritten/force-pushed head where prior is unreachable fails closed."""
+        obs = issue_lock_worktree.read_merge_sync_provenance(
+            self.tmp, prior_head_sha=self.shas["prior"],
+            synced_head_sha=self.shas["unrelated"],
+        )
+        self.assertFalse(obs["is_merge_sync"])
+
+    def test_missing_args_fail_closed(self):
+        obs = issue_lock_worktree.read_merge_sync_provenance(
+            self.tmp, prior_head_sha=None, synced_head_sha=self.shas["synced"],
+        )
+        self.assertFalse(obs["is_merge_sync"])
+
+
+# ──────────────────── merge-sync dead-session recovery ──────────────────────
+
+
+def make_dead_lock(worktree, **over):
+    pid = dead_pid()
+    lock = {
+        "issue_number": ISSUE,
+        "branch_name": BRANCH,
+        "worktree_path": worktree,
+        "remote": REMOTE,
+        "org": ORG,
+        "repo": REPO,
+        "session_pid": pid,
+        "pid": pid,
+        "claimant": {"username": IDENTITY, "profile": PROFILE},
+        "work_lease": {
+            "operation_type": issue_lock_store.AUTHOR_ISSUE_WORK_LEASE,
+            "issue_number": ISSUE,
+            "branch": BRANCH,
+            "worktree_path": worktree,
+            "claimant": {"username": IDENTITY, "profile": PROFILE},
+            "expires_at": future_ts(),
+        },
+    }
+    lock.update(over)
+    return lock
+
+
+def sync_prov(prior, synced, **over):
+    d = {
+        "prior_head_sha": prior,
+        "synced_head_sha": synced,
+        "probe_ok": True,
+        "prior_present": True,
+        "synced_present": True,
+        "prior_is_ancestor": True,
+        "synced_is_merge": True,
+        "first_parent_reaches_prior": True,
+        "is_merge_sync": True,
+        "first_parent_sha": prior,
+        "parent_count": 2,
+        "proof": f"{synced} merged base into branch above {prior}",
+        "reasons": [],
+    }
+    d.update(over)
+    return d
+
+
+class TestMergeSyncRecovery(unittest.TestCase):
+    def setUp(self):
+        self.tmp = tempfile.mkdtemp()
+        self.shas = build_merge_sync_repo(self.tmp)
+        self.prior = self.shas["prior"]
+        self.synced = self.shas["synced"]
+
+    def _assess(self, **over):
+        lock = over.pop("_lock", None) or make_dead_lock(self.tmp)
+        kw = dict(
+            issue_number=ISSUE, branch_name=BRANCH, worktree_path=self.tmp,
+            remote=REMOTE, org=ORG, repo=REPO, identity=IDENTITY, profile=PROFILE,
+            current_branch=BRANCH, porcelain_status="",
+            head_sha=self.prior, remote_head_sha=self.synced,
+            pr_head_sha=self.synced, pr_number=PR_NUMBER,
+            competing_live_locks=[], candidate_branches=[BRANCH],
+            current_pid=os.getpid(),
+            remote_branch_exists=True,
+            sync_provenance=sync_prov(self.prior, self.synced),
+        )
+        kw.update(over)
+        return issue_lock_recovery.assess_dead_session_lock_recovery(lock, **kw)
+
+    def test_merge_sync_drift_is_recoverable(self):
+        """AC3/AC4: dead session, recorded head is a merge-sync ancestor of PR head."""
+        res = self._assess()
+        self.assertEqual(res["outcome"], issue_lock_recovery.RECOVERY_SANCTIONED, res["reasons"])
+        self.assertEqual(
+            res["evidence"]["head_relation"],
+            issue_lock_recovery.HEAD_RELATION_REMOTE_MERGE_SYNCED,
+        )
+        self.assertEqual(res["evidence"]["accepted_head"], self.synced)
+
+    def test_missing_provenance_fails_closed(self):
+        """No server-derived provenance → cannot accept a remote ahead of local."""
+        res = self._assess(sync_provenance=None)
+        self.assertEqual(res["outcome"], issue_lock_recovery.REFUSED)
+
+    def test_non_ancestor_recorded_head_fails_closed(self):
+        """AC7: provenance that does not prove ancestry is rejected."""
+        res = self._assess(
+            sync_provenance=sync_prov(
+                self.prior, self.synced, prior_is_ancestor=False, is_merge_sync=False,
+                reasons=["prior head is not an ancestor"],
+            )
+        )
+        self.assertEqual(res["outcome"], issue_lock_recovery.REFUSED)
+
+    def test_force_pushed_history_fails_closed(self):
+        """AC8: a rewritten head (not a merge sync) stays protected."""
+        res = self._assess(
+            sync_provenance=sync_prov(
+                self.prior, self.synced, is_merge_sync=False, synced_is_merge=False,
+                reasons=["not a merge-based sync"],
+            )
+        )
+        self.assertEqual(res["outcome"], issue_lock_recovery.REFUSED)
+
+    def test_provenance_for_other_commits_fails_closed(self):
+        """Provenance whose endpoints differ from the heads under assessment is rejected."""
+        res = self._assess(
+            sync_provenance=sync_prov("f" * 40, self.synced),
+        )
+        self.assertEqual(res["outcome"], issue_lock_recovery.REFUSED)
+
+    def test_dirty_worktree_fails_closed(self):
+        """AC11: dirty worktrees remain protected."""
+        res = self._assess(porcelain_status=" M feature.txt\n")
+        self.assertEqual(res["outcome"], issue_lock_recovery.REFUSED)
+
+    def test_live_owner_fails_closed(self):
+        """AC10: a live recorded owner is not a dead-session recovery."""
+        lock = make_dead_lock(self.tmp, session_pid=os.getpid(), pid=os.getpid())
+        res = self._assess(_lock=lock)
+        self.assertEqual(res["outcome"], issue_lock_recovery.REFUSED)
+
+    def test_competing_claimant_fails_closed(self):
+        """AC13: a competing live lock blocks recovery."""
+        res = self._assess(
+            competing_live_locks=[{
+                "issue_number": ISSUE, "branch_name": BRANCH,
+                "worktree_path": "/some/other/wt", "pid": os.getpid(),
+            }]
+        )
+        self.assertEqual(res["outcome"], issue_lock_recovery.REFUSED)
+
+    def test_wrong_branch_fails_closed(self):
+        """AC9: worktree on a different branch fails closed."""
+        res = self._assess(current_branch="fix/issue-8710-other")
+        self.assertEqual(res["outcome"], issue_lock_recovery.REFUSED)
+
+    def test_wrong_identity_fails_closed(self):
+        res = self._assess(identity="intruder")
+        self.assertEqual(res["outcome"], issue_lock_recovery.REFUSED)
+
+    def test_pr_head_mismatch_fails_closed(self):
+        """The open PR must sit at the synced remote head."""
+        res = self._assess(pr_head_sha="e" * 40)
+        self.assertEqual(res["outcome"], issue_lock_recovery.REFUSED)
+
+    def test_owning_pr_evidence_for_merge_sync(self):
+        res = self._assess()
+        ev = issue_lock_recovery.owning_pr_recovery_evidence(res)
+        self.assertIsNotNone(ev)
+        self.assertEqual(ev["pr_number"], PR_NUMBER)
+        self.assertEqual(ev["head_sha"], self.synced)
+        self.assertEqual(
+            ev["head_relation"],
+            issue_lock_recovery.HEAD_RELATION_REMOTE_MERGE_SYNCED,
+        )
+
+    def test_recovered_owning_pr_from_persisted_record(self):
+        res = self._assess()
+        record = issue_lock_recovery.build_recovery_record(res, recovered_at=future_ts(0))
+        lock = {"issue_number": ISSUE, "branch_name": BRANCH,
+                "dead_session_recovery": record}
+        rebuilt = issue_lock_recovery.recovered_owning_pr_from_lock(lock)
+        self.assertIsNotNone(rebuilt)
+        self.assertEqual(rebuilt["head_sha"], self.synced)
+        self.assertEqual(
+            rebuilt["head_relation"],
+            issue_lock_recovery.HEAD_RELATION_REMOTE_MERGE_SYNCED,
+        )
+
+
+class TestExistingRelationsUnchanged(unittest.TestCase):
+    """AC14/AC15: equal-head recovery still works; merge-sync did not weaken it."""
+
+    def setUp(self):
+        self.tmp = tempfile.mkdtemp()
+        self.shas = build_merge_sync_repo(self.tmp)
+
+    def test_equal_head_recovery_still_sanctioned(self):
+        # Worktree at prior head; remote also at prior head → the #753 equal case.
+        prior = self.shas["prior"]
+        lock = make_dead_lock(self.tmp)
+        res = issue_lock_recovery.assess_dead_session_lock_recovery(
+            lock, issue_number=ISSUE, branch_name=BRANCH, worktree_path=self.tmp,
+            remote=REMOTE, org=ORG, repo=REPO, identity=IDENTITY, profile=PROFILE,
+            current_branch=BRANCH, porcelain_status="",
+            head_sha=prior, remote_head_sha=prior,
+            pr_head_sha=prior, pr_number=PR_NUMBER,
+            competing_live_locks=[], candidate_branches=[BRANCH],
+            current_pid=os.getpid(), remote_branch_exists=True,
+        )
+        self.assertEqual(res["outcome"], issue_lock_recovery.RECOVERY_SANCTIONED, res["reasons"])
+        self.assertEqual(
+            res["evidence"]["head_relation"], issue_lock_recovery.HEAD_RELATION_EQUAL,
+        )
+
+
+class TestUpdatePrWrapperPartialFailure(unittest.TestCase):
+    """AC5/AC16: the tool advances the remote head then refreshes the durable lock.
+
+    When the durable refresh fails after the remote advance, the tool must report a
+    partial lifecycle failure and NOT a fully successful synchronization. Exact PR-
+    head / base-head pinning is preserved (delegated to the real preflight, stubbed
+    here only to isolate the post-update lifecycle branch).
+    """
+
+    def setUp(self):
+        import gitea_mcp_server as gms  # noqa: E402
+        self.gms = gms
+        self._orig = {}
+
+        def _patch(name, value):
+            self._orig[name] = getattr(gms, name)
+            setattr(gms, name, value)
+
+        _patch("get_profile", lambda *a, **k: {
+            "allowed_operations": ["gitea.branch.push"],
+            "forbidden_operations": [],
+            "profile_name": "prgs-author",
+        })
+        _patch("_role_kind", lambda *a, **k: "author")
+        _patch("_profile_operation_gate", lambda *a, **k: None)
+        _patch("_permission_block_report", lambda *a, **k: {})
+        _patch("_resolve", lambda *a, **k: ("gitea.prgs.cc", ORG, REPO))
+        _patch("_verify_role_mutation_workspace", lambda *a, **k: None)
+        _patch("_get_workspace_porcelain", lambda *a, **k: "")
+        _patch("_canonical_local_git_root", lambda *a, **k: "/x")
+        _patch("_master_parity_block", lambda *a, **k: None)
+        _patch("_auth", lambda *a, **k: {"token": "x"})
+        _patch("repo_api_url", lambda *a, **k: "http://api")
+        _patch("_redact", lambda s: s)
+        _patch("_work_lease_claimant", lambda *a, **k: {
+            "username": IDENTITY, "profile": PROFILE,
+        })
+        _patch("_prove_author_ownership_for_pr", lambda *a, **k: {
+            "has_author_lock": True, "matched_issue": ISSUE,
+            "matched_via": "branch", "linked_issues": [ISSUE],
+            "recovered_owning_pr": None, "reasons": [],
+        })
+
+        # Real preflight is unit-tested elsewhere; stub it to isolate the
+        # post-update durable-lock lifecycle branch under test.
+        orig_pf = gms.pr_sync_status.assess_update_pr_branch_preflight
+        self._orig_pf = orig_pf
+        gms.pr_sync_status.assess_update_pr_branch_preflight = (
+            lambda *a, **k: {"mutation_allowed": True, "reasons": [], "performed": False}
+        )
+
+        # Sequence the two GET /pulls calls: OLD before update, NEW after.
+        self._pull_calls = {"n": 0}
+
+        def fake_api_request(method, url, auth, *a, **k):
+            m = method.upper()
+            if m == "GET" and url.endswith(f"/pulls/{PR_NUMBER}"):
+                self._pull_calls["n"] += 1
+                head = OLD if self._pull_calls["n"] == 1 else NEW1
+                return {
+                    "state": "open",
+                    "head": {"sha": head, "ref": BRANCH},
+                    "base": {"sha": BASE, "ref": "master"},
+                    "mergeable": True, "title": "t", "body": "b",
+                }
+            if m == "GET" and "/branches/" in url:
+                return {"commit": {"id": BASE}}
+            if m == "POST" and "/update" in url:
+                return {}
+            return {}
+
+        _patch("api_request", fake_api_request)
+
+    def tearDown(self):
+        for name, value in self._orig.items():
+            setattr(self.gms, name, value)
+        self.gms.pr_sync_status.assess_update_pr_branch_preflight = self._orig_pf
+
+    def _run(self):
+        return self.gms.gitea_update_pr_branch_by_merge(
+            pr_number=PR_NUMBER,
+            expected_pr_head_sha=OLD,
+            expected_base_head_sha=BASE,
+            remote=REMOTE,
+            worktree_path="/tmp/branches/wt-871",
+        )
+
+    def test_partial_failure_when_refresh_fails(self):
+        self._orig["apply_durable_lock_head_refresh"] = (
+            self.gms.issue_lock_store.apply_durable_lock_head_refresh
+        )
+        self.gms.issue_lock_store.apply_durable_lock_head_refresh = (
+            lambda **k: {"refreshed": False, "reasons": ["forced refresh failure"]}
+        )
+        try:
+            res = self._run()
+        finally:
+            self.gms.issue_lock_store.apply_durable_lock_head_refresh = (
+                self._orig["apply_durable_lock_head_refresh"]
+            )
+        self.assertTrue(res["performed"])
+        self.assertEqual(res["new_pr_head_sha"], NEW1)
+        self.assertFalse(res["success"])
+        self.assertTrue(res["partial_lifecycle_failure"])
+        self.assertFalse(res["durable_lock_refreshed"])
+
+    def test_full_success_when_refresh_succeeds(self):
+        self._orig["apply_durable_lock_head_refresh"] = (
+            self.gms.issue_lock_store.apply_durable_lock_head_refresh
+        )
+        self.gms.issue_lock_store.apply_durable_lock_head_refresh = (
+            lambda **k: {"refreshed": True, "read_after_write_ok": True,
+                         "new_head": NEW1, "reasons": ["ok"]}
+        )
+        try:
+            res = self._run()
+        finally:
+            self.gms.issue_lock_store.apply_durable_lock_head_refresh = (
+                self._orig["apply_durable_lock_head_refresh"]
+            )
+        self.assertTrue(res["success"])
+        self.assertTrue(res["performed"])
+        self.assertTrue(res["durable_lock_refreshed"])
+        self.assertTrue(res["fully_synchronized"])
+        self.assertEqual(res["new_pr_head_sha"], NEW1)
+
+
+if __name__ == "__main__":
+    unittest.main()
@@ -0,0 +1,107 @@
+"""Documentation acceptance for the MCP restart governance ADR (#656).
+
+Enforces issue #656 acceptance criteria:
+
+* AC1 — policy document exists with an authorization matrix and the recorded
+  v1 decision (controller approval + automated safety gates).
+* AC2 — restart is stated as a last resort with enumerated narrower recoveries.
+* AC3 — a unilateral LLM full restart with affected sessions is forbidden.
+* AC4 — break-glass conditions are listed.
+* AC5 — the ADR is linked to #655, #652, #653, #630, #642, and is cross-linked
+  from the safety model and the web-console deployment boundary docs.
+"""
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+ADR = REPO_ROOT / "docs" / "architecture" / "mcp-restart-governance.md"
+ADR_BASENAME = "mcp-restart-governance.md"
+
+CROSS_LINK_DOCS = (
+    REPO_ROOT / "docs" / "safety-model.md",
+    REPO_ROOT / "docs" / "webui-deployment.md",
+)
+
+LINKED_ISSUES = ("#655", "#652", "#653", "#630", "#642")
+POLICY_IDS = ("RG-01", "RG-02", "RG-03", "RG-04", "RG-05", "RG-06", "RG-07", "RG-08")
+
+
+def _read(path: Path) -> str:
+    assert path.is_file(), f"missing {path.relative_to(REPO_ROOT)}"
+    return path.read_text(encoding="utf-8")
+
+
+def test_ac1_adr_exists_with_matrix_and_v1_decision():
+    text = _read(ADR)
+    lower = text.lower()
+    assert text.lstrip().startswith("#"), "ADR lacks a title"
+    assert "#656" in text
+    assert "authorization matrix" in lower
+    # The matrix is a real table with the worker and privileged roles.
+    for role in ("author", "reviewer", "merger", "reconciler", "controller",
+                 "operator", "admin"):
+        assert role in lower, f"authorization matrix missing role {role!r}"
+    # Recorded v1 decision.
+    assert "restart-governance/v1" in text
+    assert "controller approval" in lower and "automated safety gates" in lower
+
+
+def test_ac2_restart_is_last_resort_with_narrower_recoveries():
+    text = _read(ADR)
+    lower = text.lower()
+    assert "last resort" in lower
+    # Enumerated narrower recoveries precede full restart on the ladder.
+    for rung in ("reconnect", "rebind", "scoped restart", "full restart",
+                 "host"):
+        assert rung in lower, f"recovery ladder missing rung {rung!r}"
+
+
+def test_ac3_forbids_unilateral_llm_full_restart_with_affected_sessions():
+    text = _read(ADR)
+    lower = text.lower()
+    assert "forbidden" in lower
+    assert "llm" in lower and "restart" in lower
+    assert "unilateral" in lower
+    # A worker role must not perform or authorize full/host restart.
+    assert "must not" in lower
+
+
+def test_ac4_break_glass_conditions_listed():
+    text = _read(ADR)
+    lower = text.lower()
+    assert "break-glass" in lower
+    assert "incident" in lower
+    assert "audit" in lower
+
+
+def test_ac5_adr_links_issue_lineage():
+    text = _read(ADR)
+    for issue in LINKED_ISSUES:
+        assert issue in text, f"ADR must link issue {issue}"
+
+
+def test_ac5_safety_model_and_deployment_cross_link_adr():
+    for path in CROSS_LINK_DOCS:
+        text = _read(path)
+        assert ADR_BASENAME in text, (
+            f"{path.relative_to(REPO_ROOT)} must cross-link {ADR_BASENAME} "
+            f"(issue #656 acceptance criterion 5)"
+        )
+
+
+def test_policy_ids_present_for_enforcement_code():
+    text = _read(ADR)
+    for pid in POLICY_IDS:
+        assert pid in text, f"policy id {pid} missing from ADR"
+
+
+def test_failure_behavior_denies_on_ambiguity():
+    text = _read(ADR)
+    lower = text.lower()
+    assert "ambiguous" in lower and "deny" in lower
+
+
+def test_cross_links_do_not_embed_secrets():
+    for path in (ADR,) + CROSS_LINK_DOCS:
+        text = _read(path)
+        for marker in ("ghp_", "BEGIN PRIVATE KEY", "Authorization: Bearer"):
+            assert marker not in text, f"{path} contains {marker!r}"
@@ -0,0 +1,146 @@
+"""Tests for the MCP restart-path inventory and guards (#657).
+
+Covers:
+* the registry is well-formed and every path is classified;
+* unknown restart attempts fail closed (AC "fail closed on unknown restart");
+* the previously-unguarded full-restart primitives stay guarded/absent
+  against the real source tree (AC "tests for at least one previously
+  unguarded path");
+* pkill of the daemon is still classified as contamination (#630, AC3);
+* the inventory doc and module stay in lock-step.
+"""
+
+import os
+import tempfile
+import unittest
+from pathlib import Path
+
+import mcp_restart_paths as rp
+import runtime_recovery_guard
+
+REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+DOC_PATH = os.path.join(REPO_ROOT, "docs", "mcp-restart-path-inventory.md")
+
+
+class TestRegistryWellformed(unittest.TestCase):
+    def test_registry_is_wellformed(self):
+        # Must not raise.
+        rp.assert_registry_wellformed()
+
+    def test_every_path_has_valid_classification(self):
+        for path in rp.iter_restart_paths():
+            self.assertIn(path.classification, rp.VALID_CLASSIFICATIONS)
+            self.assertTrue(path.guard.strip(), path.path_id)
+            self.assertTrue(path.references, path.path_id)
+            self.assertTrue(path.locations, path.path_id)
+
+    def test_ids_are_unique(self):
+        ids = [p.path_id for p in rp.iter_restart_paths()]
+        self.assertEqual(len(ids), len(set(ids)))
+
+    def test_covers_every_classification(self):
+        present = {p.classification for p in rp.iter_restart_paths()}
+        self.assertEqual(present, set(rp.VALID_CLASSIFICATIONS))
+
+
+class TestUnknownAttemptFailsClosed(unittest.TestCase):
+    def test_unknown_path_raises(self):
+        with self.assertRaises(rp.UnknownRestartPathError):
+            rp.assert_restart_attempt_registered("totally_novel_restart_hack")
+
+    def test_get_unknown_raises(self):
+        with self.assertRaises(rp.UnknownRestartPathError):
+            rp.get_restart_path("nope")
+
+    def test_registered_attempt_returns_path(self):
+        path = rp.assert_restart_attempt_registered("manual_daemon_kill")
+        self.assertEqual(path.classification, rp.CLASS_FORBIDDEN)
+
+
+class TestDaemonNeverSelfReplaces(unittest.TestCase):
+    """Previously-unguarded full-restart primitive: daemon self-replacement."""
+
+    def test_no_self_replacement_in_source(self):
+        # The live daemon modules must contain no os.execv/os.kill/os._exit
+        # self-restart call. Must not raise.
+        rp.assert_no_daemon_self_replacement(REPO_ROOT)
+
+    def test_scanner_flags_injected_violation(self):
+        # Guard the guard: prove the scanner catches a real self-replace call.
+        with tempfile.TemporaryDirectory() as tmp:
+            bad = Path(tmp) / "gitea_mcp_server.py"
+            bad.write_text(
+                "import os\n"
+                "def restart():\n"
+                "    os.execv('/usr/bin/python', ['python'])\n",
+                encoding="utf-8",
+            )
+            found = rp.scan_daemon_self_replacement(tmp)
+            self.assertTrue(found)
+            with self.assertRaises(AssertionError):
+                rp.assert_no_daemon_self_replacement(tmp)
+
+    def test_scanner_ignores_comment_and_docstring_mentions(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            ok = Path(tmp) / "gitea_mcp_server.py"
+            ok.write_text(
+                "import os\n"
+                "# NOT os.execv() to re-point the interpreter here.\n"
+                '"""Never calls os._exit to restart."""\n'
+                "value = 1\n",
+                encoding="utf-8",
+            )
+            self.assertEqual(rp.scan_daemon_self_replacement(tmp), [])
+
+
+class TestLegacyAutoRestartHelperRemoved(unittest.TestCase):
+    """Previously-unguarded full-restart path: _trigger_mcp_auto_restart."""
+
+    def test_helper_absent_in_source(self):
+        # Must not raise: helper was removed in #685.
+        rp.assert_auto_restart_helper_absent(REPO_ROOT)
+
+    def test_scanner_flags_reintroduced_helper(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            bad = Path(tmp) / "mcp_server.py"
+            bad.write_text(
+                "def _trigger_mcp_auto_restart():\n    return True\n",
+                encoding="utf-8",
+            )
+            with self.assertRaises(AssertionError):
+                rp.assert_auto_restart_helper_absent(tmp)
+
+
+class TestPkillStaysForbidden(unittest.TestCase):
+    """AC3: pkill of the daemon remains forbidden/contaminating (#630)."""
+
+    def test_manual_daemon_kill_registered_as_forbidden(self):
+        path = rp.get_restart_path("manual_daemon_kill")
+        self.assertEqual(path.classification, rp.CLASS_FORBIDDEN)
+
+    def test_pkill_classified_as_contamination(self):
+        assessment = runtime_recovery_guard.assess_recovery_command(
+            "pkill -f mcp_server.py"
+        )
+        self.assertTrue(assessment["contaminated"])
+
+    def test_read_only_probe_not_contamination(self):
+        assessment = runtime_recovery_guard.assess_recovery_command(
+            "ps aux | grep mcp_server"
+        )
+        self.assertFalse(assessment["contaminated"])
+
+
+class TestInventoryDocInSync(unittest.TestCase):
+    def test_doc_exists(self):
+        self.assertTrue(os.path.exists(DOC_PATH), DOC_PATH)
+
+    def test_doc_mentions_every_path_id(self):
+        with open(DOC_PATH, encoding="utf-8") as handle:
+            doc = handle.read()
+        for path in rp.iter_restart_paths():
+            self.assertIn(path.path_id, doc, f"doc missing {path.path_id}")
+
+
+if __name__ == "__main__":
+    unittest.main()
@@ -12,6 +12,59 @@ import merged_cleanup_reconcile as mcr  # noqa: E402


 class TestMergedCleanupAssessment(unittest.TestCase):
+    def test_issue_851_plan_order_worktree_then_reassess_then_remote(self):
+        """#851 dry-run plan: remove worktree, reassess ownership, then remote."""
+        plan = mcr.plan_cleanup_execution_order(
+            remote_assessment={"safe_to_delete_remote": True},
+            local_assessment={"safe_to_remove_worktree": True},
+        )
+        actions = [s["action"] for s in plan]
+        self.assertEqual(
+            actions,
+            [
+                "remove_local_worktree",
+                "reassess_branch_ownership",
+                "delete_remote_branch",
+            ],
+        )
+        self.assertEqual(plan[0]["phase"], 1)
+        self.assertEqual(plan[-1]["phase"], 3)
+        self.assertIn("independently_safe", plan[0]["reason"])
+        self.assertIn("reassessment", plan[-1]["reason"])
+
+    def test_issue_851_plan_remote_only_when_worktree_not_safe(self):
+        plan = mcr.plan_cleanup_execution_order(
+            remote_assessment={"safe_to_delete_remote": True},
+            local_assessment={"safe_to_remove_worktree": False},
+        )
+        self.assertEqual([s["action"] for s in plan], ["delete_remote_branch"])
+        self.assertNotIn("reassess_branch_ownership", [s["action"] for s in plan])
+
+    def test_issue_851_plan_worktree_only_when_remote_not_safe(self):
+        plan = mcr.plan_cleanup_execution_order(
+            remote_assessment={"safe_to_delete_remote": False},
+            local_assessment={"safe_to_remove_worktree": True},
+        )
+        self.assertEqual([s["action"] for s in plan], ["remove_local_worktree"])
+
+    def test_issue_851_entry_includes_planned_execution_order(self):
+        entry = mcr.build_pr_cleanup_entry(
+            pr={
+                "number": 848,
+                "title": "Closes #844",
+                "body": "",
+                "merged_at": "2026-07-23T00:00:00Z",
+                "head": {"ref": "fix/issue-844-x", "sha": "a" * 40},
+            },
+            project_root="/tmp/not-a-real-root",
+            open_pr_heads=set(),
+            remote_branch_exists=True,
+            head_on_master=True,
+            delete_capability_allowed=True,
+        )
+        self.assertIn("planned_execution_order", entry)
+        self.assertIsInstance(entry["planned_execution_order"], list)
+
    def test_extract_linked_issue_from_closes(self):
        issue = mcr.extract_linked_issue(
            "feat: cleanup (Closes #269)",
@@ -134,13 +134,35 @@ class TestClassification(unittest.TestCase):
        self.assertEqual(cls, wca.CLASS_ACTIVE_OPEN_PR)
        self.assertFalse(wca.is_removable(cls))

-    def test_stale_clean_issue_worktree_removable(self):
-        # Scenario 5: clean issue worktree, TTL expired, no lock -> removable.
+    def test_stale_clean_issue_worktree_needs_merged_pr_proof(self):
+        # Scenario 5 (#858): age is not proof that the branch landed, so a
+        # TTL-expired issue worktree stays active work. Only authoritative
+        # merged-PR evidence makes it removable, which is what keeps a
+        # worktree holding unmerged commits from being reclaimed by age.
        cls = wca.classify_worktree(
            workflow_type=wca.WORKFLOW_ISSUE_WORK,
            is_dirty=False,
            ttl_expired=True,
        )
+        self.assertEqual(cls, wca.CLASS_ACTIVE_ISSUE_WORK)
+        self.assertFalse(wca.is_removable(cls))
+
+        cls = wca.classify_worktree(
+            workflow_type=wca.WORKFLOW_ISSUE_WORK,
+            is_dirty=False,
+            ttl_expired=True,
+            merged_pr_cleanup={"proven": True},
+        )
+        self.assertEqual(cls, wca.CLASS_CLEAN_STALE_REMOVABLE)
+        self.assertTrue(wca.is_removable(cls))
+
+    def test_stale_clean_conflict_fix_worktree_removable(self):
+        # conflict_fix keeps the original TTL rule; #858 changed issue work only.
+        cls = wca.classify_worktree(
+            workflow_type=wca.WORKFLOW_CONFLICT_FIX,
+            is_dirty=False,
+            ttl_expired=True,
+        )
        self.assertEqual(cls, wca.CLASS_CLEAN_STALE_REMOVABLE)
        self.assertTrue(wca.is_removable(cls))

@@ -46,6 +46,7 @@ from webui.worktree_scanner import load_hygiene_snapshot, snapshot_to_dict as wo
 from webui.worktree_views import render_worktrees_page
 from webui.runtime_health import load_runtime_snapshot, snapshot_to_dict as runtime_snapshot_to_dict
 from webui.runtime_views import render_runtime_page
+from webui.timeline import load_timeline, snapshot_to_dict as timeline_snapshot_to_dict
 from webui.system_health import (
    API_PATH as SYSTEM_HEALTH_API_PATH,
    load_system_health,
@@ -449,6 +450,104 @@ async def api_console_security_model(_request: Request) -> JSONResponse:
    })


+def _query_int(request: Request, key: str) -> int | None:
+    """Parse an optional integer query parameter; None when absent/invalid."""
+    raw = request.query_params.get(key)
+    if raw is None or not str(raw).strip():
+        return None
+    try:
+        return int(str(raw).strip())
+    except (TypeError, ValueError):
+        return None
+
+
+def _derive_remote(host: str) -> str:
+    """Map a Gitea host to its known short remote name (control-plane scope key)."""
+    text = (host or "").lower()
+    if "prgs" in text:
+        return "prgs"
+    if "dadeschools" in text:
+        return "dadeschools"
+    return text.split(".")[0] if text else ""
+
+
+def _timeline_comment_source(host: str, org: str, repo: str):
+    """Build a fail-soft CTH-comment fetcher for one repo, or None when offline.
+
+    Returns a callable ``(kind, number) -> list[comment]``. Credentials or
+    network failures raise inside the callable so ``load_timeline`` degrades the
+    handoff source rather than the whole timeline. Offline test mode yields no
+    live source so the handoff section reports ``not run``.
+    """
+    import os
+
+    from gitea_auth import api_fetch_page, get_auth_header, repo_api_url
+
+    offline = (os.environ.get("WEBUI_TEST_OFFLINE") or "").strip().lower() in {"1", "true", "yes"}
+    if offline:
+        return None
+    auth = get_auth_header(host)
+    if not auth:
+        return None
+
+    def _fetch(kind: str, number: int) -> list:
+        segment = "pulls" if kind == "pr" else "issues"
+        url = f"{repo_api_url(host, org, repo)}/{segment}/{int(number)}/comments"
+        comments: list = []
+        page = 1
+        while page <= 20:
+            raw, meta = api_fetch_page(url, auth, page=page, limit=50)
+            comments.extend(raw)
+            if bool(meta["is_final_page"]):
+                break
+            page += 1
+        return comments
+
+    return _fetch
+
+
+async def api_v1_timeline(request: Request) -> JSONResponse:
+    """Read-only workflow-event timeline (#637). Filter by issue/PR/session."""
+    from webui.queue_loader import _host_from_url  # host normalisation helper
+
+    registry, error = _load_project_registry()
+    if error is not None:
+        return JSONResponse(error.to_dict(), status_code=500)
+    project = registry.projects[0] if registry.projects else None
+
+    org = request.query_params.get("org") or (project.gitea_owner if project else "")
+    repo = request.query_params.get("repo") or (project.repo_name if project else "")
+    host = _host_from_url(project.remote_host) if project else ""
+    remote = request.query_params.get("remote") or _derive_remote(host)
+
+    if not (remote and org and repo):
+        return JSONResponse(
+            {
+                "error": "timeline_scope_unresolved",
+                "detail": "no project in registry and no remote/org/repo query params provided",
+            },
+            status_code=400,
+        )
+
+    comment_source = _timeline_comment_source(host, org, repo) if (host and org and repo) else None
+
+    snapshot = load_timeline(
+        remote=remote,
+        org=org,
+        repo=repo,
+        issue=_query_int(request, "issue"),
+        pr=_query_int(request, "pr"),
+        session=(request.query_params.get("session") or None),
+        limit=_query_int(request, "limit"),
+        offset=_query_int(request, "offset"),
+        comment_source=comment_source,
+    )
+    # A filter no surviving source can carry is refused, not answered empty:
+    # a 200 with zero events would tell the operator no such activity exists.
+    status_code = 200 if snapshot.ok else 422
+    return JSONResponse(timeline_snapshot_to_dict(snapshot), status_code=status_code)
+
+
 async def method_not_allowed(request: Request, _exc: Exception) -> Response:
    path = request.url.path
    if path in _AUDIT_MUTATION_PATHS and request.method == "POST":
@@ -488,6 +587,7 @@ def create_app(*, bind_host: str | None = None) -> Starlette:
            Route("/api/prompts", api_prompts, methods=["GET"]),
            Route("/runtime", runtime, methods=["GET"]),
            Route("/api/runtime", api_runtime, methods=["GET"]),
+            Route("/api/v1/timeline", api_v1_timeline, methods=["GET"]),
            Route("/audit", audit, methods=["GET", "POST"]),
            Route("/api/audit", api_audit, methods=["GET", "POST"]),
            Route("/worktrees", worktrees, methods=["GET"]),
@@ -0,0 +1,906 @@
+"""Workflow-event and conversation timeline model (#637, Phase 1).
+
+Operators cannot browse a unified timeline of workflow events, decisions,
+tool calls, and handoffs: the evidence is scattered across control-plane
+events, Gitea canonical handoff comments, and local logs. This module defines
+one durable, versioned event schema and per-source adapters that normalise
+those scattered records into a single ``WorkflowEvent`` stream, plus a
+read-only query layer (filter by issue / PR / session, stable ordering,
+pagination) that the ``/api/v1/timeline`` route serves.
+
+Design rules honoured here:
+
+- **Read-only.** Sources are read; nothing is mutated. The control-plane
+  database is opened through a ``mode=ro`` URI so a missing or unwritable DB
+  degrades to a reason instead of creating directories or running migrations.
+- **Fail-soft per source.** An unavailable source degrades to a status with a
+  reason rather than raising, and a source that could not run is never
+  rendered as an empty-and-healthy timeline.
+- **Answerable filters only.** Each source declares which filter dimensions it
+  can actually answer. A filter dimension no source that ran can carry is
+  refused with an explicit reason rather than silently matching nothing: an
+  empty page from an unanswerable filter reads to an operator as "no such
+  activity", which is a different — and false — statement.
+- **Redaction at the boundary, fail closed.** Every free-text field (event
+  messages, redacted tool arguments, decision/proof text) is run through the
+  console redaction policy before it leaves this module, and *before* any
+  structured value is derived from it — evidence references are extracted from
+  redacted text, then independently revalidated before serialization. An
+  unredactable value becomes the placeholder, and a value that cannot be proven
+  safe is dropped — an unredacted payload is never emitted, and a generation
+  error never drops raw data to a caller or a log.
+- **Stable ordering.** Events sort by ``(timestamp, source_rank, event_key)``
+  with a deterministic tiebreak, so pagination is stable across calls and
+  events with equal or missing timestamps keep a fixed order.
+
+Non-goals (from the issue): no full chat replay, no mutation of historical
+events, no unredacted tool-argument storage.
+"""
+
+from __future__ import annotations
+
+import re
+import sqlite3
+from dataclasses import dataclass, replace
+from datetime import datetime, timezone
+from typing import Any, Callable, Iterable
+
+import control_plane_db
+from webui import console_redaction
+
+# The schema is versioned so consumers can branch on shape. Bump on any
+# breaking change to WorkflowEvent's serialized form.
+TIMELINE_SCHEMA_VERSION = 1
+
+# Known event sources and their deterministic ordering rank. When two events
+# carry the same timestamp, the source rank breaks the tie before the
+# per-source event key, so a control-plane event and a handoff comment minted
+# in the same second always sort in a fixed order.
+SOURCE_CONTROL_PLANE = "control_plane"
+SOURCE_GITEA_HANDOFF = "gitea_handoff"
+_SOURCE_RANK = {
+    SOURCE_CONTROL_PLANE: 0,
+    SOURCE_GITEA_HANDOFF: 1,
+}
+
+# The filter dimensions the query layer accepts.
+FILTER_ISSUE = "issue"
+FILTER_PR = "pr"
+FILTER_SESSION = "session"
+
+# Which dimensions each source can actually answer. This is a property of the
+# underlying records, not of the query code: the control-plane ``events`` table
+# is (event_id, work_item_id, event_type, message, created_at) and carries no
+# session identity at all, so no control-plane event can ever match a session
+# filter. A CTH handoff comment can declare its session as a field, so the
+# handoff source answers all three. Filtering on a dimension the surviving
+# sources cannot carry is refused in ``load_timeline`` rather than answered
+# with an empty page.
+_SOURCE_FILTER_SUPPORT: dict[str, tuple[str, ...]] = {
+    SOURCE_CONTROL_PLANE: (FILTER_ISSUE, FILTER_PR),
+    SOURCE_GITEA_HANDOFF: (FILTER_ISSUE, FILTER_PR, FILTER_SESSION),
+}
+
+# Why a source cannot answer a dimension, for the refusal reason an operator reads.
+_SOURCE_FILTER_LIMITS: dict[tuple[str, str], str] = {
+    (SOURCE_CONTROL_PLANE, FILTER_SESSION): (
+        "control-plane events carry no session identity "
+        "(the events table has no session column)"
+    ),
+}
+
+# A timestamp far in the future so events with no parseable timestamp sort
+# last (after everything real) instead of first, without raising.
+_MISSING_TS_SORT = "9999-12-31T23:59:59Z"
+
+
+def _parse_ts(value: str | None) -> str | None:
+    """Normalise a timestamp to ``...Z`` UTC, or None when unparseable."""
+    if not value:
+        return None
+    text = str(value).strip()
+    if not text:
+        return None
+    candidate = text[:-1] + "+00:00" if text.endswith("Z") else text
+    try:
+        parsed = datetime.fromisoformat(candidate)
+    except ValueError:
+        return None
+    if parsed.tzinfo is None:
+        parsed = parsed.replace(tzinfo=timezone.utc)
+    return parsed.astimezone(timezone.utc).replace(microsecond=0).isoformat().replace("+00:00", "Z")
+
+
+def _redact(value: Any) -> Any:
+    """Redact a single free-text field, failing closed to the placeholder."""
+    if value is None:
+        return None
+    return console_redaction.redact_text(str(value))
+
+
+@dataclass(frozen=True)
+class WorkflowEvent:
+    """One normalised timeline event.
+
+    Every field is optional except ``source``/``event_type``/``event_key``
+    because sources carry different subsets. The class is frozen so an adapted
+    event is an immutable record; a consumer that needs a variant builds a new
+    one rather than mutating history.
+    """
+
+    source: str
+    event_type: str
+    event_key: str
+    timestamp: str | None = None
+    actor: str | None = None
+    role: str | None = None
+    issue_number: int | None = None
+    pr_number: int | None = None
+    session_id: str | None = None
+    tool_name: str | None = None
+    decision: str | None = None
+    message: str | None = None
+    correlation_id: str | None = None
+    evidence_refs: tuple[str, ...] = ()
+    sensitive: bool = False
+
+    def sort_key(self) -> tuple[str, int, str]:
+        return (
+            self.timestamp or _MISSING_TS_SORT,
+            _SOURCE_RANK.get(self.source, 99),
+            self.event_key,
+        )
+
+    def to_dict(self) -> dict[str, Any]:
+        return {
+            "source": self.source,
+            "event_type": self.event_type,
+            "event_key": self.event_key,
+            "timestamp": self.timestamp,
+            "actor": self.actor,
+            "role": self.role,
+            "issue_number": self.issue_number,
+            "pr_number": self.pr_number,
+            "session_id": self.session_id,
+            "tool_name": self.tool_name,
+            "decision": self.decision,
+            "message": self.message,
+            "correlation_id": self.correlation_id,
+            "evidence_refs": list(self.evidence_refs),
+            "sensitive": self.sensitive,
+        }
+
+
+# --------------------------------------------------------------------------- #
+# Adapters — pure functions from a source's raw records to WorkflowEvents.     #
+# Each is total: a malformed record is skipped, never raised on.               #
+# --------------------------------------------------------------------------- #
+
+# Event types whose payload is treated as sensitive and always redaction-hard
+# (they can carry lease/session provenance or tool arguments).
+_SENSITIVE_EVENT_HINTS = ("lease", "capability", "token", "auth", "secret")
+
+# Reference tokens (issue/PR/comment ids) and SHAs parsed out of proof text.
+_EVIDENCE_REF_RE = re.compile(r"(?:#|PR\s*#?|issue\s*#?|comment\s*#?)(\d+)", re.IGNORECASE)
+
+# A commit reference is only recognised when the text *declares* it as one.
+# A bare lowercase hex run is not evidence of anything: at 40 characters it is
+# exactly the shape of a Gitea personal access token, and at 7 it also matches
+# ordinary words such as "defaced". Requiring an anchoring keyword keeps real
+# references ("commit abc1234", "at head a209756...", "base caaae9b6") usable
+# while refusing to lift an undeclared secret-shaped run out of free text.
+_SHA_RE = re.compile(
+    r"(?i:\b(?:commit|sha|head|base|parent|revision|rev|merge[- ]base)\b[\s:=@#]*)"
+    r"([0-9a-f]{7,40})\b"
+)
+
+# Shapes a serialized evidence reference is allowed to take. Anything else is
+# dropped rather than emitted.
+_REF_ISSUE_SHAPE = re.compile(r"^#[0-9]{1,9}$")
+_REF_SHA_SHAPE = re.compile(r"^[0-9a-f]{7,40}$")
+
+# A long undelimited hex run with no declaring context is treated as credential
+# material wherever it appears, never as an identifier.
+_BARE_SECRET_SHAPE = re.compile(r"^[0-9a-f]{32,}$")
+
+# An event type reads like an identifier, but a stored one is externally
+# influenced: any producer that writes the control-plane ``events`` table
+# chooses the string. It reaches ``to_dict`` verbatim, so it is validated here
+# rather than trusted because of where it came from.
+_CP_EVENT_TYPE_SHAPE = re.compile(r"^[A-Za-z][A-Za-z0-9._:+-]{0,63}$")
+
+# Emitted in place of a value that cannot be proven safe. Deliberately not a
+# plausible workflow type: an unsafe value is refused, never quietly rewritten
+# into a different valid-looking one that would misdescribe the record.
+UNSAFE_EVENT_TYPE = "unsafe:redacted"
+
+# Emitted for a CTH heading that is not a declared member of ``CTH_TYPES``. The
+# contract is enforced on write (``format_cth_body``) and on assess; the read
+# path the timeline uses enforces it too rather than assuming it was.
+UNKNOWN_HANDOFF_EVENT_TYPE = "handoff:unrecognized"
+
+# A source record id is a plain integer in both sources it comes from: the
+# control-plane ``events`` primary key and a Gitea comment id. ``event_key`` is
+# serialized verbatim and is the pagination tiebreak, so anything else is
+# refused rather than interpolated into it.
+_RECORD_ID_SHAPE = re.compile(r"^[0-9]{1,19}$")
+
+
+def _kind_to_numbers(kind: str | None, number: int | None) -> tuple[int | None, int | None]:
+    """Map a control-plane work-item (kind, number) to (issue_no, pr_no)."""
+    if number is None:
+        return (None, None)
+    if kind == "pr":
+        return (None, int(number))
+    if kind == "issue":
+        return (int(number), None)
+    return (None, None)
+
+
+def _correlation_for(kind: str | None, number: int | None) -> str | None:
+    if number is None or kind not in ("issue", "pr"):
+        return None
+    return f"{kind}#{number}"
+
+
+def _extract_evidence_refs(*texts: str | None) -> tuple[str, ...]:
+    """Extract issue/PR and declared-commit references from **redacted** text.
+
+    Callers must pass text that has already been through :func:`_redact`; this
+    function derives a structured field from its input, so extracting ahead of
+    redaction would republish whatever redaction was about to remove. Every
+    reference is revalidated by :func:`_validated_evidence_refs` before it is
+    serialized.
+    """
+    refs: list[str] = []
+    for text in texts:
+        if not text:
+            continue
+        for match in _EVIDENCE_REF_RE.finditer(text):
+            token = f"#{match.group(1)}"
+            if token not in refs:
+                refs.append(token)
+        for match in _SHA_RE.finditer(text):
+            token = match.group(1)
+            if token not in refs:
+                refs.append(token)
+    return tuple(refs)
+
+
+def _validated_evidence_refs(refs: Iterable[str]) -> tuple[tuple[str, ...], bool]:
+    """Independently revalidate references immediately before serialization.
+
+    Extraction is not trusted on its own. A reference survives only when it has
+    a known reference shape and is unchanged by a second redaction pass — a
+    value the redaction policy would alter is credential material that must not
+    be emitted as a structured field. A full 40-character SHA stays usable
+    because extraction only accepts a hex run the source text explicitly
+    declared as a commit. Returns ``(safe_refs, dropped_any)``; ``dropped_any``
+    marks the event sensitive so the drop is visible rather than silent.
+    """
+    safe: list[str] = []
+    dropped = False
+    for ref in refs or ():
+        try:
+            token = str(ref).strip()
+            if not token:
+                continue
+            recognised = bool(_REF_ISSUE_SHAPE.match(token) or _REF_SHA_SHAPE.match(token))
+            if not recognised:
+                dropped = True
+                continue
+            if _redact(token) != token:
+                dropped = True
+                continue
+            if token not in safe:
+                safe.append(token)
+        except Exception:
+            # Fail closed: a reference that cannot be proven safe is dropped.
+            dropped = True
+            continue
+    return (tuple(safe), dropped)
+
+
+def _safe_session_id(value: Any) -> str | None:
+    """Return a session identifier only when it is safe to emit.
+
+    The value is authoritative source data — a session the record names for
+    itself — but it is still free text. It is dropped when redaction alters it
+    or when it is a bare secret-shaped hex run, so a credential parked in a
+    session field can never reach the payload or be echoed back by a filter.
+    """
+    if value is None:
+        return None
+    text = str(value).strip()
+    if not text:
+        return None
+    if _BARE_SECRET_SHAPE.match(text):
+        return None
+    return text if _redact(text) == text else None
+
+
+def _safe_record_id(value: Any) -> str | None:
+    """Return a source record id only when it is a plain numeric identifier.
+
+    ``event_key`` is serialized verbatim and is the deterministic pagination
+    tiebreak, so an id is interpolated into it only when it has the shape both
+    real sources actually produce. A record whose identity cannot be trusted is
+    refused by the caller rather than keyed on.
+    """
+    if value is None or isinstance(value, bool):
+        return None
+    if isinstance(value, int):
+        return str(value)
+    text = str(value).strip()
+    return text if _RECORD_ID_SHAPE.match(text) else None
+
+
+def _safe_cp_event_type(value: Any) -> tuple[str, bool]:
+    """Validate a stored control-plane event type. Returns ``(type, unsafe)``.
+
+    The stored value is externally influenced — whichever producer wrote the
+    ``events`` row chose the string — and ``to_dict`` serializes it verbatim, so
+    it passes a boundary of its own instead of relying on the one ``message``
+    passes. A value survives only when it is an ordinary identifier, is not a
+    bare secret-shaped hex run, and is unchanged by a redaction pass. Anything
+    else fails closed to :data:`UNSAFE_EVENT_TYPE`: the record stays visible as
+    an audit entry, but the value itself is never republished — not verbatim,
+    not partially sanitized, and not rewritten into some other valid-looking
+    type that would misdescribe what happened.
+    """
+    text = ("" if value is None else str(value)).strip()
+    if not text:
+        return ("", False)
+    if _BARE_SECRET_SHAPE.match(text):
+        return (UNSAFE_EVENT_TYPE, True)
+    if not _CP_EVENT_TYPE_SHAPE.match(text):
+        return (UNSAFE_EVENT_TYPE, True)
+    if _redact(text) != text:
+        return (UNSAFE_EVENT_TYPE, True)
+    return (text, False)
+
+
+def _safe_echo(value: Any) -> Any:
+    """Guard a scalar that is echoed back rather than derived from a record.
+
+    Query scope and filter values are caller-supplied and are reflected in the
+    response so an operator can see what was asked. Reflection is still
+    emission: a value redaction would alter, or a bare secret-shaped hex run, is
+    replaced by the placeholder instead of being echoed verbatim. Ordinary
+    scope and filter values pass through untouched.
+    """
+    if value is None or isinstance(value, (int, bool)):
+        return value
+    text = str(value)
+    if _BARE_SECRET_SHAPE.match(text.strip()):
+        return console_redaction.REDACTED
+    return _redact(text)
+
+
+def adapt_cp_events(rows: Iterable[dict[str, Any]]) -> list[WorkflowEvent]:
+    """Adapt control-plane ``events`` rows (joined to work_items) into events.
+
+    Each row is expected to carry ``event_id``, ``event_type``, ``message``,
+    ``created_at`` and the joined work-item ``kind``/``number``. Rows missing
+    an id or type are skipped so a partially written table never raises.
+    """
+    events: list[WorkflowEvent] = []
+    for row in rows or []:
+        try:
+            event_id = _safe_record_id(row.get("event_id"))
+            raw_event_type = (row.get("event_type") or "").strip()
+            if event_id is None or not raw_event_type:
+                continue
+            # The stored type is source data, not a trusted constant: validate
+            # it before it is serialized, exactly as `message` below is redacted
+            # before it is serialized.
+            event_type, event_type_unsafe = _safe_cp_event_type(raw_event_type)
+            kind = row.get("kind")
+            number = row.get("number")
+            issue_no, pr_no = _kind_to_numbers(kind, number)
+            sensitive = event_type_unsafe or any(
+                hint in raw_event_type.lower() for hint in _SENSITIVE_EVENT_HINTS
+            )
+            events.append(
+                WorkflowEvent(
+                    source=SOURCE_CONTROL_PLANE,
+                    event_type=event_type,
+                    event_key=f"cp:{event_id}",
+                    timestamp=_parse_ts(row.get("created_at")),
+                    issue_number=issue_no,
+                    pr_number=pr_no,
+                    # No session_id: the control-plane events table is
+                    # (event_id, work_item_id, event_type, message, created_at)
+                    # and records no session. Inventing one from the work item
+                    # or the message text would be a guess, so this source
+                    # declares the session dimension unsupported instead
+                    # (_SOURCE_FILTER_SUPPORT) and the query layer refuses a
+                    # session filter it cannot honestly answer.
+                    message=_redact(row.get("message")),
+                    correlation_id=_correlation_for(kind, number),
+                    sensitive=sensitive,
+                )
+            )
+        except Exception:
+            # A single malformed row must not sink the whole adaptation.
+            continue
+    return events
+
+
+def adapt_cth_comments(
+    comments: Iterable[dict[str, Any]],
+    *,
+    kind: str,
+    number: int,
+) -> list[WorkflowEvent]:
+    """Adapt Gitea Canonical Thread Handoff (CTH) comments into events.
+
+    Only comments that parse as a CTH (``canonical_thread_handoff.parse_cth_comment``)
+    become events; ordinary comments are ignored. ``kind``/``number`` scope the
+    events to the issue or PR the comments belong to.
+    """
+    # Imported lazily so this module has no import-time dependency on the
+    # handoff parser when only the control-plane adapter is used.
+    from canonical_thread_handoff import is_known_cth_type, parse_cth_comment
+
+    # ``kind``/``number`` are interpolated into event_key and correlation_id, so
+    # they are normalised once here. A scope this adapter cannot express is
+    # refused outright rather than serialized into an identifier.
+    kind = (kind or "").strip().lower()
+    if kind not in ("issue", "pr"):
+        return []
+    try:
+        number = int(number)
+    except (TypeError, ValueError):
+        return []
+
+    issue_no, pr_no = _kind_to_numbers(kind, number)
+    correlation = _correlation_for(kind, number)
+    events: list[WorkflowEvent] = []
+    for comment in comments or []:
+        try:
+            body = comment.get("body") or ""
+            parsed = parse_cth_comment(body)
+            if not parsed:
+                continue
+            fields = parsed.get("fields") or {}
+            cth_type = parsed.get("cth_type") or ""
+            comment_id = _safe_record_id(comment.get("id"))
+            if comment_id is None:
+                continue
+            # The CTH heading is free text: the parser accepts whatever follows
+            # "## CTH:", and only the write and assess paths check it against
+            # the contract. Check it here too — an unrecognised heading is
+            # reported as such rather than serialized into event_type, so
+            # arbitrary, malformed, or secret-shaped heading content has no way
+            # through. Declared types are preserved exactly.
+            cth_type_known = is_known_cth_type(cth_type)
+            # Redaction runs first, and every derived value is taken from the
+            # redacted text — deriving evidence refs from the raw proof would
+            # re-emit exactly what redaction was about to remove.
+            decision = _redact(fields.get("decision"))
+            proof = _redact(fields.get("proof"))
+            next_action = _redact(fields.get("next action"))
+            refs, refs_dropped = _validated_evidence_refs(
+                _extract_evidence_refs(proof, decision)
+            )
+            events.append(
+                WorkflowEvent(
+                    source=SOURCE_GITEA_HANDOFF,
+                    event_type=(
+                        f"handoff:{cth_type.strip()}"
+                        if cth_type_known
+                        else UNKNOWN_HANDOFF_EVENT_TYPE
+                    ),
+                    event_key=f"cth:{kind}:{number}:{comment_id}",
+                    timestamp=_parse_ts(comment.get("created_at")),
+                    actor=_redact((comment.get("user") or {}).get("login")),
+                    role=_redact(fields.get("next owner")),
+                    issue_number=issue_no,
+                    pr_number=pr_no,
+                    # A CTH names its own session when the producer records one;
+                    # it is read from that declared field, never inferred from
+                    # unrelated text.
+                    session_id=_safe_session_id(fields.get("session")),
+                    decision=decision,
+                    message=next_action or _redact(fields.get("status")),
+                    correlation_id=correlation,
+                    evidence_refs=refs,
+                    sensitive=refs_dropped or not cth_type_known,
+                )
+            )
+        except Exception:
+            continue
+    return events
+
+
+# --------------------------------------------------------------------------- #
+# Read-only control-plane event source.                                       #
+# --------------------------------------------------------------------------- #
+
+_CP_EVENTS_QUERY = """
+SELECT e.event_id   AS event_id,
+       e.event_type AS event_type,
+       e.message    AS message,
+       e.created_at AS created_at,
+       w.kind       AS kind,
+       w.number     AS number
+FROM events e
+JOIN work_items w ON e.work_item_id = w.work_item_id
+WHERE w.remote = ? AND w.org = ? AND w.repo = ?
+"""
+
+
+@dataclass(frozen=True)
+class SourceStatus:
+    """Fail-soft status for one timeline source.
+
+    ``supported_filters`` states which filter dimensions this source's records
+    can carry; ``unsupported_filters`` names the requested dimensions it cannot,
+    so an operator can see *why* a source contributed nothing rather than being
+    left to read an empty list as an absence of activity.
+    """
+
+    name: str
+    ok: bool
+    reason: str | None = None
+    count: int = 0
+    supported_filters: tuple[str, ...] = ()
+    unsupported_filters: tuple[str, ...] = ()
+
+    def to_dict(self) -> dict[str, Any]:
+        return {
+            "name": self.name,
+            "ok": self.ok,
+            "reason": self.reason,
+            "count": self.count,
+            "supported_filters": list(self.supported_filters),
+            "unsupported_filters": list(self.unsupported_filters),
+        }
+
+
+def _cp_status(*, ok: bool, reason: str | None = None, count: int = 0) -> SourceStatus:
+    return SourceStatus(
+        SOURCE_CONTROL_PLANE,
+        ok=ok,
+        # A failure reason is serialized like any other field and is often an
+        # exception string carrying a path or a transport error, so it crosses
+        # the redaction boundary too. Static reasons pass through unchanged.
+        reason=_redact(reason),
+        count=count,
+        supported_filters=_SOURCE_FILTER_SUPPORT[SOURCE_CONTROL_PLANE],
+    )
+
+
+def _handoff_status(*, ok: bool, reason: str | None = None, count: int = 0) -> SourceStatus:
+    return SourceStatus(
+        SOURCE_GITEA_HANDOFF,
+        ok=ok,
+        # Same boundary as the control-plane status: this reason can quote an
+        # error raised by a live authenticated fetch.
+        reason=_redact(reason),
+        count=count,
+        supported_filters=_SOURCE_FILTER_SUPPORT[SOURCE_GITEA_HANDOFF],
+    )
+
+
+def read_cp_events(
+    *,
+    remote: str,
+    org: str,
+    repo: str,
+    db_path: str | None = None,
+) -> tuple[list[WorkflowEvent], SourceStatus]:
+    """Read scoped control-plane events read-only. Never creates the DB.
+
+    Opens the SQLite file through a ``mode=ro`` URI: a health/timeline read
+    must never create directories or run the schema migration that
+    ``ControlPlaneDB()`` performs on construction. A missing or unreadable DB
+    degrades to a status with a reason.
+    """
+    path = (db_path or control_plane_db.default_db_path()).strip()
+    conn: sqlite3.Connection | None = None
+    try:
+        conn = sqlite3.connect(f"file:{path}?mode=ro", uri=True)
+        conn.row_factory = sqlite3.Row
+        cursor = conn.execute(_CP_EVENTS_QUERY, (remote, org, repo))
+        rows = [dict(r) for r in cursor.fetchall()]
+    except sqlite3.OperationalError as exc:
+        return ([], _cp_status(ok=False, reason=f"control-plane DB unavailable: {exc}"))
+    except sqlite3.Error as exc:
+        return ([], _cp_status(ok=False, reason=f"control-plane read failed: {exc}"))
+    finally:
+        if conn is not None:
+            conn.close()
+    events = adapt_cp_events(rows)
+    return (events, _cp_status(ok=True, count=len(events)))
+
+
+# --------------------------------------------------------------------------- #
+# Filter, sort, paginate.                                                     #
+# --------------------------------------------------------------------------- #
+
+
+def filter_events(
+    events: Iterable[WorkflowEvent],
+    *,
+    issue: int | None = None,
+    pr: int | None = None,
+    session: str | None = None,
+) -> list[WorkflowEvent]:
+    """Filter events by issue number, PR number, and/or session id.
+
+    Filters are conjunctive. A filter that names a dimension an event does not
+    carry excludes that event (an issue filter excludes PR-only events).
+    """
+    out: list[WorkflowEvent] = []
+    for ev in events:
+        if issue is not None and ev.issue_number != issue:
+            continue
+        if pr is not None and ev.pr_number != pr:
+            continue
+        if session is not None and ev.session_id != session:
+            continue
+        out.append(ev)
+    return out
+
+
+def sort_events(events: Iterable[WorkflowEvent]) -> list[WorkflowEvent]:
+    """Return events in stable timeline order (ascending)."""
+    return sorted(events, key=lambda ev: ev.sort_key())
+
+
+@dataclass(frozen=True)
+class TimelinePage:
+    """One page of the sorted, filtered timeline."""
+
+    events: tuple[WorkflowEvent, ...]
+    total: int
+    limit: int
+    offset: int
+
+    @property
+    def next_offset(self) -> int | None:
+        nxt = self.offset + len(self.events)
+        return nxt if nxt < self.total else None
+
+    def to_dict(self) -> dict[str, Any]:
+        return {
+            "events": [ev.to_dict() for ev in self.events],
+            "pagination": {
+                "total": self.total,
+                "limit": self.limit,
+                "offset": self.offset,
+                "returned": len(self.events),
+                "next_offset": self.next_offset,
+                "has_more": self.next_offset is not None,
+            },
+        }
+
+
+_MAX_LIMIT = 500
+_DEFAULT_LIMIT = 50
+
+
+def _coerce_bounds(limit: int | None, offset: int | None) -> tuple[int, int]:
+    try:
+        lim = int(limit) if limit is not None else _DEFAULT_LIMIT
+    except (TypeError, ValueError):
+        lim = _DEFAULT_LIMIT
+    try:
+        off = int(offset) if offset is not None else 0
+    except (TypeError, ValueError):
+        off = 0
+    lim = max(1, min(lim, _MAX_LIMIT))
+    off = max(0, off)
+    return (lim, off)
+
+
+def paginate(events: list[WorkflowEvent], *, limit: int | None, offset: int | None) -> TimelinePage:
+    lim, off = _coerce_bounds(limit, offset)
+    window = events[off : off + lim]
+    return TimelinePage(events=tuple(window), total=len(events), limit=lim, offset=off)
+
+
+# --------------------------------------------------------------------------- #
+# Composition — load_timeline aggregates all sources, fail-soft.              #
+# --------------------------------------------------------------------------- #
+
+# A comment source is a callable that, given (kind, number), returns the raw
+# Gitea comment list for that issue/PR. The route supplies a live fail-soft
+# fetcher; tests supply a fixture. When None, the handoff source is reported as
+# not-run (never silently empty-and-healthy).
+CommentSource = Callable[[str, int], list[dict[str, Any]]]
+
+
+@dataclass(frozen=True)
+class TimelineSnapshot:
+    """One answered timeline query.
+
+    ``ok`` is False when the query could not be answered as asked — currently
+    when a requested filter dimension no surviving source can carry was
+    supplied. The page is then empty *and* the snapshot says so, because an
+    ``ok`` empty page is a claim that no such activity exists.
+    """
+
+    schema_version: int
+    remote: str
+    org: str
+    repo: str
+    filters: dict[str, Any]
+    page: TimelinePage
+    sources: tuple[SourceStatus, ...]
+    ok: bool = True
+    error: dict[str, Any] | None = None
+
+    def to_dict(self) -> dict[str, Any]:
+        return {
+            "ok": self.ok,
+            "error": self.error,
+            "schema_version": self.schema_version,
+            # Scope and filters are echoed caller input, not derived record
+            # data. Reflecting a value is still emitting it, so both cross the
+            # same boundary; ordinary scope and filter values are unchanged.
+            "scope": {
+                "remote": _safe_echo(self.remote),
+                "org": _safe_echo(self.org),
+                "repo": _safe_echo(self.repo),
+            },
+            "filters": {key: _safe_echo(value) for key, value in self.filters.items()},
+            "sources": [s.to_dict() for s in self.sources],
+            **self.page.to_dict(),
+        }
+
+
+def _unanswerable_reasons(
+    statuses: Iterable[SourceStatus], unanswerable: Iterable[str]
+) -> list[dict[str, str]]:
+    """Explain, per source, why each unanswerable dimension went unanswered."""
+    out: list[dict[str, str]] = []
+    for status in statuses:
+        for dim in unanswerable:
+            if dim not in status.supported_filters:
+                reason = _SOURCE_FILTER_LIMITS.get(
+                    (status.name, dim), f"this source's records carry no {dim} identity"
+                )
+            elif not status.ok:
+                reason = (
+                    f"this source can carry {dim} but did not run: "
+                    f"{status.reason or 'unavailable'}"
+                )
+            else:
+                continue
+            out.append({"source": status.name, "filter": dim, "reason": reason})
+    return out
+
+
+def load_timeline(
+    *,
+    remote: str,
+    org: str,
+    repo: str,
+    issue: int | None = None,
+    pr: int | None = None,
+    session: str | None = None,
+    limit: int | None = None,
+    offset: int | None = None,
+    db_path: str | None = None,
+    comment_source: CommentSource | None = None,
+) -> TimelineSnapshot:
+    """Aggregate every timeline source into one filtered, paginated snapshot.
+
+    Sources are read independently and fail soft: an unavailable source
+    contributes a ``SourceStatus`` with ``ok=False`` and a reason, and never
+    collapses the whole timeline. The handoff source only runs when a specific
+    issue or PR is requested (a handoff comment belongs to one thread) and a
+    ``comment_source`` is available; otherwise it is reported as ``not run``
+    rather than as an empty-and-healthy source.
+
+    A filter dimension that no surviving source can carry — a ``session``
+    filter when the only source that ran is the control plane, whose events
+    record no session — is refused with ``ok=False`` and a structured error
+    instead of being answered with an empty page.
+    """
+    all_events: list[WorkflowEvent] = []
+    statuses: list[SourceStatus] = []
+
+    cp_events, cp_status = read_cp_events(remote=remote, org=org, repo=repo, db_path=db_path)
+    all_events.extend(cp_events)
+    statuses.append(cp_status)
+
+    # Gitea handoff comments are thread-scoped: only fetch when the caller
+    # narrowed to one issue or PR, and only when a source was provided.
+    handoff_target: tuple[str, int] | None = None
+    if pr is not None:
+        handoff_target = ("pr", pr)
+    elif issue is not None:
+        handoff_target = ("issue", issue)
+
+    if handoff_target is None:
+        statuses.append(
+            _handoff_status(
+                ok=False,
+                reason="not run: handoff comments are thread-scoped; filter by issue or pr to include them",
+            )
+        )
+    elif comment_source is None:
+        statuses.append(
+            _handoff_status(
+                ok=False,
+                reason="not run: no comment source configured for this timeline read",
+            )
+        )
+    else:
+        kind, number = handoff_target
+        try:
+            comments = comment_source(kind, number) or []
+            handoff_events = adapt_cth_comments(comments, kind=kind, number=number)
+            all_events.extend(handoff_events)
+            statuses.append(_handoff_status(ok=True, count=len(handoff_events)))
+        except Exception as exc:  # fail soft: a fetch/parse error degrades this source only
+            statuses.append(_handoff_status(ok=False, reason=f"handoff source failed: {exc}"))
+
+    requested = tuple(
+        name
+        for name, value in ((FILTER_ISSUE, issue), (FILTER_PR, pr), (FILTER_SESSION, session))
+        if value is not None
+    )
+    statuses = [
+        replace(
+            status,
+            unsupported_filters=tuple(
+                dim for dim in requested if dim not in status.supported_filters
+            ),
+        )
+        for status in statuses
+    ]
+    filters = {"issue": issue, "pr": pr, "session": session}
+
+    # A dimension is answerable only if a source that actually ran can carry it.
+    # If none can, refuse: an empty page would assert "no such activity", which
+    # is a claim this timeline is not in a position to make.
+    answerable: set[str] = set()
+    for status in statuses:
+        if status.ok:
+            answerable.update(status.supported_filters)
+    unanswerable = tuple(dim for dim in requested if dim not in answerable)
+
+    if unanswerable:
+        return TimelineSnapshot(
+            schema_version=TIMELINE_SCHEMA_VERSION,
+            remote=remote,
+            org=org,
+            repo=repo,
+            filters=filters,
+            page=paginate([], limit=limit, offset=offset),
+            sources=tuple(statuses),
+            ok=False,
+            error={
+                "code": "filter_not_supported",
+                "unsupported_filters": list(unanswerable),
+                "detail": (
+                    "no timeline source that ran can answer "
+                    + ", ".join(f"'{dim}'" for dim in unanswerable)
+                    + "; the result is refused rather than returned empty"
+                ),
+                "sources": _unanswerable_reasons(statuses, unanswerable),
+            },
+        )
+
+    filtered = filter_events(all_events, issue=issue, pr=pr, session=session)
+    ordered = sort_events(filtered)
+    page = paginate(ordered, limit=limit, offset=offset)
+
+    return TimelineSnapshot(
+        schema_version=TIMELINE_SCHEMA_VERSION,
+        remote=remote,
+        org=org,
+        repo=repo,
+        filters=filters,
+        page=page,
+        sources=tuple(statuses),
+    )
+
+
+def snapshot_to_dict(snapshot: TimelineSnapshot) -> dict[str, Any]:
+    return snapshot.to_dict()
@@ -34,7 +34,11 @@ import subprocess
 from datetime import datetime, timezone
 from typing import Any

-from merged_cleanup_reconcile import branch_worktree_folder, read_local_worktree_state
+from merged_cleanup_reconcile import (
+    branch_worktree_folder,
+    is_head_ancestor_of_ref,
+    read_local_worktree_state,
+)
 from reviewer_worktree import parse_dirty_tracked_files, REVIEW_WORKTREE_RE

 PROTECTED_BRANCHES = frozenset({"master", "main", "dev"})
@@ -67,6 +71,14 @@ REMOVABLE_CLASSES = frozenset(
    {CLASS_CLEAN_STALE_REMOVABLE, CLASS_DETACHED_REVIEW_LEFTOVER}
 )

+# Merged-PR linkage outcomes for issue worktrees (#858). Only ``LINKAGE_MERGED``
+# is ownership proof; every other outcome leaves the worktree protected.
+LINKAGE_MERGED = "merged_pr"
+LINKAGE_OPEN = "open_pr"
+LINKAGE_NONE = "no_owning_pr"
+LINKAGE_AMBIGUOUS = "ambiguous"
+LINKAGE_UNKNOWN = "unknown"
+
 _ISSUE_REF_RE = re.compile(r"issue-(\d+)", re.IGNORECASE)
 _ISSUE_BRANCH_PREFIXES = ("feat/", "fix/", "docs/", "chore/")

@@ -169,6 +181,186 @@ def is_ttl_expired(
    return (now_dt - last).total_seconds() > ttl_hours * 3600.0


+def build_pr_index(prs: list[dict[str, Any]] | None) -> dict[str, list[dict[str, Any]]]:
+    """Index PR records by head branch for deterministic worktree linkage (#858).
+
+    Accepts Gitea PR payloads (``head`` as a dict) and pre-flattened records
+    (``head_branch``/``head_sha``). Records without a usable head branch or
+    number are dropped rather than guessed at, so a branch is only ever linked
+    to a PR the caller actually proved.
+    """
+    index: dict[str, list[dict[str, Any]]] = {}
+    for pr in prs or []:
+        head = pr.get("head")
+        if isinstance(head, dict):
+            head_branch = head.get("ref")
+            head_sha = head.get("sha")
+        else:
+            head_branch = pr.get("head_branch") or (head if isinstance(head, str) else None)
+            head_sha = pr.get("head_sha")
+        number = pr.get("number")
+        if not head_branch or number is None:
+            continue
+        try:
+            pr_number = int(number)
+        except (TypeError, ValueError):
+            continue
+        index.setdefault(str(head_branch).strip(), []).append(
+            {
+                "pr_number": pr_number,
+                "head_branch": str(head_branch).strip(),
+                "head_sha": head_sha,
+                "merged": bool(pr.get("merged") or pr.get("merged_at")),
+                "state": pr.get("state"),
+            }
+        )
+    return index
+
+
+def resolve_owning_pr(
+    *,
+    branch: str | None,
+    pr_index: dict[str, list[dict[str, Any]]] | None,
+) -> dict[str, Any]:
+    """Resolve the single PR that owns ``branch``, failing closed when unclear.
+
+    Ownership is only ``LINKAGE_MERGED`` when exactly one PR claims the branch
+    and that PR is merged. Several distinct PRs on one branch is a competing
+    claim (``LINKAGE_AMBIGUOUS``), and a still-open owner is reported as
+    ``LINKAGE_OPEN`` — both keep the worktree protected while still exposing
+    the PR number the audit resolved.
+    """
+    if pr_index is None:
+        return {
+            "status": LINKAGE_UNKNOWN,
+            "pr_number": None,
+            "candidate_pr_numbers": [],
+            "reasons": ["live PR state was not supplied; ownership unproven"],
+        }
+    branch_name = (branch or "").strip()
+    if not branch_name:
+        return {
+            "status": LINKAGE_UNKNOWN,
+            "pr_number": None,
+            "candidate_pr_numbers": [],
+            "reasons": ["worktree has no attached branch; ownership unproven"],
+        }
+
+    candidates = list(pr_index.get(branch_name) or [])
+    numbers = sorted({c["pr_number"] for c in candidates})
+    if not candidates:
+        return {
+            "status": LINKAGE_NONE,
+            "pr_number": None,
+            "candidate_pr_numbers": [],
+            "reasons": [f"no PR claims branch '{branch_name}'"],
+        }
+    if len(numbers) > 1:
+        return {
+            "status": LINKAGE_AMBIGUOUS,
+            "pr_number": None,
+            "candidate_pr_numbers": numbers,
+            "reasons": [
+                f"branch '{branch_name}' is claimed by competing PRs {numbers}; "
+                "ownership is ambiguous"
+            ],
+        }
+
+    owner = candidates[0]
+    pr_number = owner["pr_number"]
+    if owner.get("head_branch") != branch_name:
+        return {
+            "status": LINKAGE_UNKNOWN,
+            "pr_number": pr_number,
+            "candidate_pr_numbers": numbers,
+            "reasons": [
+                f"PR #{pr_number} head branch '{owner.get('head_branch')}' does not "
+                f"match worktree branch '{branch_name}'"
+            ],
+        }
+    if not owner.get("merged"):
+        return {
+            "status": LINKAGE_OPEN,
+            "pr_number": pr_number,
+            "candidate_pr_numbers": numbers,
+            "pr_head_sha": owner.get("head_sha"),
+            "reasons": [f"owning PR #{pr_number} is not merged"],
+        }
+    return {
+        "status": LINKAGE_MERGED,
+        "pr_number": pr_number,
+        "candidate_pr_numbers": numbers,
+        "pr_head_sha": owner.get("head_sha"),
+        "reasons": [],
+    }
+
+
+def assess_merged_pr_worktree_cleanup(
+    *,
+    linkage: dict[str, Any] | None,
+    head_sha: str | None,
+    head_in_master: bool | None,
+    is_dirty: bool,
+    has_open_pr: bool,
+    has_active_lease: bool,
+    has_active_issue_lock: bool,
+    is_protected: bool,
+    has_live_session: bool = False,
+) -> dict[str, Any]:
+    """Decide whether a merged issue worktree satisfies the full cleanup policy.
+
+    Every condition must be independently proven: conclusive merged-PR
+    ownership, agreement between the worktree branch and the PR head branch,
+    containment of the worktree head in authoritative master (which is what
+    proves no unmerged commits remain), absence of any open/competing PR,
+    lease, issue lock, or live session, a clean tree, and a worktree that is
+    not the protected control checkout. Anything unknown blocks.
+    """
+    link = linkage or {
+        "status": LINKAGE_UNKNOWN,
+        "pr_number": None,
+        "reasons": ["no linkage assessment supplied"],
+    }
+    status = link.get("status")
+    reasons: list[str] = []
+
+    if status != LINKAGE_MERGED:
+        reasons.extend(
+            link.get("reasons") or ["owning PR could not be conclusively identified"]
+        )
+    if is_protected:
+        reasons.append("worktree is protected or the stable control checkout")
+    if is_dirty:
+        reasons.append("worktree has uncommitted changes")
+    if has_open_pr:
+        reasons.append("worktree branch has an open PR")
+    if has_active_lease:
+        reasons.append("worktree has an active lease")
+    if has_active_issue_lock:
+        reasons.append("an active issue lock references this branch")
+    if has_live_session:
+        reasons.append("a live process or session is using this worktree")
+    if not head_sha:
+        reasons.append("worktree head sha is unknown")
+    if head_in_master is None:
+        reasons.append("containment of the worktree head in master is unknown")
+    elif not head_in_master:
+        reasons.append(
+            "worktree head is not contained in authoritative master "
+            "(unmerged commits remain)"
+        )
+
+    proven = not reasons
+    return {
+        "linkage_status": status,
+        "pr_number": link.get("pr_number"),
+        "pr_head_sha": link.get("pr_head_sha"),
+        "head_in_master": head_in_master,
+        "proven": proven,
+        "block_reasons": reasons,
+    }
+
+
 def classify_worktree(
    *,
    workflow_type: str,
@@ -181,6 +373,8 @@ def classify_worktree(
    ttl_expired: bool = False,
    is_protected: bool = False,
    metadata_known: bool = True,
+    merged_pr_cleanup: dict[str, Any] | None = None,
+    has_live_session: bool = False,
 ) -> str:
    """Classify a worktree, safety-first: any preservation signal wins.

@@ -199,6 +393,8 @@ def classify_worktree(
        return CLASS_ACTIVE_ISSUE_WORK  # never auto-deleted (criterion 8)
    if has_active_issue_lock:
        return CLASS_ACTIVE_ISSUE_WORK
+    if has_live_session:
+        return CLASS_ACTIVE_ISSUE_WORK  # a live session still owns this tree
    if not metadata_known or workflow_type == WORKFLOW_UNKNOWN:
        return CLASS_UNSAFE_UNKNOWN  # never auto-deleted without proof

@@ -207,7 +403,15 @@ def classify_worktree(
        if is_detached or branch_gone:
            return CLASS_DETACHED_REVIEW_LEFTOVER
        return CLASS_CLEAN_STALE_REMOVABLE
-    # issue_work / conflict_fix: only removable once the TTL has expired.
+    if workflow_type == WORKFLOW_ISSUE_WORK:
+        # #858: an issue worktree becomes removable only on authoritative
+        # merged-PR evidence satisfying the whole cleanup policy. Age alone
+        # never proves the branch landed, so TTL cannot qualify one by itself
+        # — otherwise a worktree holding unmerged commits would be reclaimed.
+        if (merged_pr_cleanup or {}).get("proven"):
+            return CLASS_CLEAN_STALE_REMOVABLE
+        return CLASS_ACTIVE_ISSUE_WORK
+    # conflict_fix: only removable once the TTL has expired.
    if ttl_expired:
        return CLASS_CLEAN_STALE_REMOVABLE
    return CLASS_ACTIVE_ISSUE_WORK
@@ -400,6 +604,20 @@ def remove_worktree(project_root: str, path: str) -> dict[str, Any]:
    }


+def head_contained_in_ref(
+    project_root: str, head_sha: str | None, ref: str | None
+) -> bool | None:
+    """Return True when ``head_sha`` is already contained in ``ref``.
+
+    Shares :mod:`merged_cleanup_reconcile`'s ancestry check so the audit and
+    the PR-scoped reconciler agree on what "already landed" means (#858).
+    Returns None when containment cannot be determined, which fails closed.
+    """
+    if not head_sha or not ref:
+        return None
+    return is_head_ancestor_of_ref(project_root, head_sha, ref)
+
+
 def _is_under_branches(project_root: str, path: str) -> bool:
    branches_root = os.path.join(os.path.abspath(project_root), "branches")
    return os.path.abspath(path or "").startswith(branches_root + os.sep)
@@ -413,16 +631,30 @@ def audit_branches_directory(
    active_issue_branches: set[str] | None = None,
    now: datetime | str | None = None,
    ttl_hours: float = DEFAULT_TTL_HOURS,
+    pr_index: dict[str, list[dict[str, Any]]] | None = None,
+    leased_issue_numbers: set[int] | None = None,
+    live_session_paths: set[str] | None = None,
+    master_ref: str | None = None,
 ) -> dict[str, Any]:
    """Classify every session-owned worktree under ``branches/``.

    Read-only: shells out to git for discovery and dirty state, then applies
    the pure classifier. Returns per-worktree classifications, counts, the
    list of removable candidates, and the ``git worktree list`` proof.
+
+    ``pr_index`` (see :func:`build_pr_index`) supplies the authoritative PR
+    ownership used to link issue worktrees to their merged PR (#858).
+    ``master_ref`` is the ref a worktree head must be contained in before it
+    can be considered landed. Both are optional and their absence only ever
+    fails closed: without them no issue worktree becomes removable.
    """
    open_pr_branches = open_pr_branches or set()
    leased_branches = leased_branches or set()
    active_issue_branches = active_issue_branches or set()
+    leased_issue_numbers = leased_issue_numbers or set()
+    live_session_paths = {
+        os.path.abspath(p) for p in (live_session_paths or set()) if p
+    }

    worktrees: list[dict[str, Any]] = []
    for entry in list_worktrees(project_root):
@@ -433,12 +665,42 @@ def audit_branches_directory(
        )
        dirty_state = read_worktree_dirty(path)
        is_dirty = bool(dirty_state.get("dirty"))
+        head_sha = entry.get("head")
+        linkage = resolve_owning_pr(branch=branch, pr_index=pr_index)
        metadata = build_worktree_metadata(
-            path=path, branch=branch, head_sha=entry.get("head")
+            path=path,
+            branch=branch,
+            head_sha=head_sha,
+            pr_number=linkage.get("pr_number"),
        )
        has_open_pr = bool(branch) and branch in open_pr_branches
-        has_active_lease = bool(branch) and branch in leased_branches
+        # A lease on issue N protects that issue's own work worktree. It must
+        # not incidentally protect a baseline/review scratch tree that merely
+        # carries the same issue marker in its name, which would change the
+        # classification of worktrees this policy does not own.
+        has_active_lease = (bool(branch) and branch in leased_branches) or (
+            metadata["workflow_type"] == WORKFLOW_ISSUE_WORK
+            and metadata.get("issue_number") is not None
+            and metadata["issue_number"] in leased_issue_numbers
+        )
        has_active_lock = bool(branch) and branch in active_issue_branches
+        has_live_session = bool(path) and os.path.abspath(path) in live_session_paths
+        head_in_master = (
+            head_contained_in_ref(project_root, head_sha, master_ref)
+            if master_ref
+            else None
+        )
+        merged_pr_cleanup = assess_merged_pr_worktree_cleanup(
+            linkage=linkage,
+            head_sha=head_sha,
+            head_in_master=head_in_master,
+            is_dirty=is_dirty,
+            has_open_pr=has_open_pr,
+            has_active_lease=has_active_lease,
+            has_active_issue_lock=has_active_lock,
+            is_protected=is_protected,
+            has_live_session=has_live_session,
+        )
        ttl_expired = is_ttl_expired(
            last_used_at=metadata.get("last_used_at"), now=now, ttl_hours=ttl_hours
        )
@@ -452,6 +714,8 @@ def audit_branches_directory(
            branch_gone=branch is None and not entry.get("detached"),
            ttl_expired=ttl_expired,
            is_protected=is_protected,
+            merged_pr_cleanup=merged_pr_cleanup,
+            has_live_session=has_live_session,
        )
        metadata["cleanup_eligibility"] = classification
        worktrees.append(
@@ -463,7 +727,10 @@ def audit_branches_directory(
                "has_open_pr": has_open_pr,
                "has_active_lease": has_active_lease,
                "has_active_issue_lock": has_active_lock,
+                "has_live_session": has_live_session,
                "is_protected": is_protected,
+                "merged_pr_linkage": linkage,
+                "merged_pr_cleanup": merged_pr_cleanup,
                "classification": classification,
                "removable": is_removable(classification),
            }