feat(observability): optional self-hosted Sentry instrumentation for MCP workflow failures (Closes #606)

Add an env-var-gated, off-by-default Sentry SDK integration so MCP runtime
errors, fail-closed workflow blockers, lease/terminal-lock/stale-runtime
collisions, and recurring watchdog check-ins are visible in a self-hosted
Sentry at https://sentry.prgs.cc/. Gitea stays the source of truth; Sentry is
observe-only.

New module `sentry_observability.py` mirrors the `gitea_audit` conventions
(env-gated, best-effort, redacting):

- Config from MCP_SENTRY_ENABLED / SENTRY_DSN / SENTRY_ENVIRONMENT /
  SENTRY_RELEASE / MCP_SENTRY_TRACES_SAMPLE_RATE / MCP_SENTRY_ENABLE_LOGS.
  Active only when enabled AND a DSN is present; otherwise a hard no-op.
- Fail OPEN for observability (never blocks a tool success path) and fail
  CLOSED for redaction (drop a field rather than risk leaking it).
- `scrub_event` before_send/before_send_log hook + allowlisted tags: no
  tokens/passwords/keychain ids/DSNs/cookies, no raw session-state or full
  prompt bodies (session_id -> 12-char hash), no full filesystem paths
  (worktree path -> coarse category). Reuses incident_bridge + gitea_audit
  scrubbers.
- capture_exception, capture_workflow_blocker (with canonical next action),
  and monitor_checkin with six stable cron slugs (stale lease scan, terminal
  lock scan, allocator health, namespace health, dashboard freshness,
  reconciler cleanup).
- `sentry_sdk` is a lazily-imported optional dependency; the module imports
  and no-ops cleanly when the package is absent.

Wiring in gitea_mcp_server.py (additive, guarded, best-effort):
- init_sentry() in __main__ before mcp.run.
- capture_exception in the `_audited` failure path; capture_workflow_blocker
  in `_audit_pr_result` BLOCKED/FAILED path.
- allocator + namespace-health watchdog check-ins at their MCP tool sites
  (domain modules left pure).

Also: pin `sentry-sdk==2.20.0` (optional), document the six env vars in
`.env.example`, and add `docs/observability/sentry-integration.md` covering
project creation in https://sentry.prgs.cc/, DSN handling, local/dev/prod
config, redaction guarantees, and coexistence with the #612 incident bridge.

Tests: tests/test_sentry_observability.py (36 cases) cover disabled / enabled /
missing-DSN / missing-SDK, redaction, exception capture, workflow-blocker
capture, and cron check-in behaviour. Full suite: 2632 passed, 6 skipped.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

.env.example

@@ -39,6 +39,27 @@ GITEA_AUDIT_LOG=/path/to/gitea-mcp-audit.log
 # only — never the token value. Surfaced by gitea_get_profile.
 GITEA_TOKEN_SOURCE=GITEA_TOKEN
 
+# ── Optional self-hosted Sentry observability (#606) ────────────────────────
+# Emits runtime errors, fail-closed workflow blockers, lease/terminal-lock/
+# stale-runtime collisions, and watchdog cron check-ins to a SELF-HOSTED Sentry
+# (https://sentry.prgs.cc/) — never Sentry Cloud. Gitea stays the source of
+# truth; Sentry is observe-only. OFF by default: with MCP_SENTRY_ENABLED unset
+# or SENTRY_DSN empty, nothing is initialised and no events are sent.
+#
+# Master gate. Truthy = 1/true/yes/on. Both this AND SENTRY_DSN are required.
+MCP_SENTRY_ENABLED=0
+# DSN for the self-hosted project (create a `gitea-tools-mcp` project in
+# https://sentry.prgs.cc/ and copy its DSN). Never commit a real DSN.
+SENTRY_DSN=
+# Deployment environment tag (local/dev/prod). Defaults to "development".
+SENTRY_ENVIRONMENT=development
+# Optional release identifier (e.g. a git SHA or version string).
+SENTRY_RELEASE=
+# Performance-trace sample rate, 0.0–1.0 (clamped). Default 0.0 (traces off).
+MCP_SENTRY_TRACES_SAMPLE_RATE=0.0
+# Set to 1 to forward Python logs to Sentry as structured logs. Default off.
+MCP_SENTRY_ENABLE_LOGS=0
+
 # Optional canonical runtime-profile config (#19). Instead of the fields above,
 # point every LLM launcher at ONE JSON file of named profiles and select one.
 # Secrets are referenced (keychain id / env var name), never inlined. See

docs/observability/sentry-integration.md

@@ -0,0 +1,138 @@
+# Self-hosted Sentry observability for the Gitea MCP server (#606)
+
+Optional, **off-by-default** instrumentation that reports MCP runtime errors,
+fail-closed workflow blockers, lease / terminal-lock / stale-runtime
+collisions, and recurring watchdog check-ins to a **self-hosted** Sentry at
+`https://sentry.prgs.cc/`.
+
+> **Gitea remains the source of truth.** Sentry is observe-only. It never
+> approves, merges, closes, or otherwise mutates Gitea workflow state, and it
+> never bypasses leases, #332, workflow roles, or the MCP gates. Sentry alerts
+> may only feed the *sanctioned* Gitea issue/comment path via the #612 incident
+> bridge — never a direct write.
+
+Implemented by [`sentry_observability.py`](../../sentry_observability.py).
+
+---
+
+## 1. Create the Sentry project
+
+1. Sign in to the self-hosted Sentry at **`https://sentry.prgs.cc/`** (this is
+   **not** Sentry Cloud — do not use `*.ingest.sentry.io`).
+2. Create a new **Python** project named **`gitea-tools-mcp`**.
+3. Open **Settings → Projects → gitea-tools-mcp → Client Keys (DSN)** and copy
+   the DSN. It looks like `https://<publickey>@sentry.prgs.cc/<project-id>`.
+4. **Never commit the DSN.** It is a runtime secret supplied via env var only.
+
+## 2. Configure the environment
+
+All configuration is env-var driven (see [`.env.example`](../../.env.example)):
+
+| Variable | Purpose | Default |
+|----------|---------|---------|
+| `MCP_SENTRY_ENABLED` | Master gate (`1/true/yes/on`). Required. | off |
+| `SENTRY_DSN` | Self-hosted DSN. Required. | *(empty)* |
+| `SENTRY_ENVIRONMENT` | `local` / `dev` / `prod` tag. | `development` |
+| `SENTRY_RELEASE` | Release id (git SHA or version). | *(none)* |
+| `MCP_SENTRY_TRACES_SAMPLE_RATE` | Perf-trace sample rate `0.0–1.0` (clamped). | `0.0` |
+| `MCP_SENTRY_ENABLE_LOGS` | Forward Python logs as structured logs. | off |
+
+**The feature stays completely off unless `MCP_SENTRY_ENABLED` is truthy *and*
+`SENTRY_DSN` is non-empty.** With either missing, `init_sentry()` is a no-op,
+the SDK is never initialised, and no events are sent — existing tool behaviour
+and API-call patterns are unchanged.
+
+### Per-environment examples
+
+```bash
+# local (quiet: capture errors/blockers, no traces)
+export MCP_SENTRY_ENABLED=1
+export SENTRY_DSN="https://<key>@sentry.prgs.cc/<id>"
+export SENTRY_ENVIRONMENT=local
+
+# dev (light tracing + logs)
+export MCP_SENTRY_ENABLED=1
+export SENTRY_DSN="https://<key>@sentry.prgs.cc/<id>"
+export SENTRY_ENVIRONMENT=dev
+export MCP_SENTRY_TRACES_SAMPLE_RATE=0.2
+export MCP_SENTRY_ENABLE_LOGS=1
+
+# prod (errors/blockers + low-rate tracing, release-tagged)
+export MCP_SENTRY_ENABLED=1
+export SENTRY_DSN="https://<key>@sentry.prgs.cc/<id>"
+export SENTRY_ENVIRONMENT=prod
+export SENTRY_RELEASE="$(git rev-parse --short HEAD)"
+export MCP_SENTRY_TRACES_SAMPLE_RATE=0.05
+```
+
+The optional SDK is pinned in [`requirements.txt`](../../requirements.txt)
+(`sentry-sdk==2.20.0`). It is imported lazily: if the package is absent, the
+module still imports and every entry point is a safe no-op.
+
+## 3. What is instrumented
+
+| Signal | Where | Notes |
+|--------|-------|-------|
+| Startup init | `gitea_mcp_server.py` `__main__`, before `mcp.run` | Prints a redaction-safe status line to stderr. |
+| Failing mutations (exceptions) | `_audited(...)` context manager | `capture_exception` with scrubbed tags. |
+| Fail-closed blockers / failed mutations | `_audit_pr_result(...)` (BLOCKED/FAILED) | Structured `capture_workflow_blocker` event incl. the canonical next action when available (criterion 7). |
+| Allocator watchdog check-ins | `gitea_allocate_next_work` tool | `allocator_health`, `stale_lease_scan`, `terminal_lock_scan`. |
+| Namespace-health check-in | `gitea_assess_mcp_namespace_health` tool | `namespace_health`. |
+
+All capture paths are **best-effort / fail open**: a Sentry outage or capture
+error never breaks an MCP tool success path.
+
+## 4. Cron / watchdog monitors
+
+`sentry_observability.MONITOR_SLUGS` defines stable check-in slugs:
+
+| Registry key | Sentry monitor slug | Wired at |
+|--------------|--------------------|----------|
+| `stale_lease_scan` | `gitea-mcp-stale-lease-scan` | allocator run (global lease expiry) |
+| `terminal_lock_scan` | `gitea-mcp-terminal-lock-scan` | allocator run (terminal-lock lookup) |
+| `allocator_health` | `gitea-mcp-allocator-health` | allocator run |
+| `namespace_health` | `gitea-mcp-namespace-health` | namespace-health probe |
+| `dashboard_freshness` | `gitea-mcp-dashboard-freshness` | call `monitor_checkin("dashboard_freshness", ...)` from the dashboard refresh job (#605) |
+| `reconciler_cleanup` | `gitea-mcp-reconciler-cleanup` | call `monitor_checkin("reconciler_cleanup", ...)` from the reconciler cleanup entrypoint |
+
+Create matching Cron monitors in Sentry with those slugs. Emit an
+`in_progress` check-in at job start and `ok`/`error` at completion via
+`sentry_observability.monitor_checkin(slug_key, status)`.
+
+## 5. Redaction guarantees (fail closed)
+
+Redaction fails *closed*: if a field cannot be proven safe it is dropped rather
+than sent. The `before_send` (and `before_send_log`) hook `scrub_event`
+recursively redacts every outgoing event; on any error it drops the event
+entirely. Guarantees, proven by `tests/test_sentry_observability.py`:
+
+- **No** tokens, passwords, keychain IDs, DSNs, cookies, or `user:pass@host`.
+- **No** raw session-state or full prompt/comment bodies — `session_id` is only
+  ever surfaced as a 12-char `session_id_hash`.
+- **No** private config contents or raw credential headers.
+- **No** full local filesystem paths — a worktree path collapses to a coarse
+  `worktree_category` (`author` / `reviewer` / `merger` / `reconciler` /
+  `branches` / `root` / `other`).
+- Only the allowlisted tag keys in `ALLOWED_TAG_KEYS` are ever attached.
+
+## 6. Coexistence with GlitchTip / the #612 incident bridge
+
+This is the **outbound** path (MCP → Sentry SDK). It complements — it does not
+replace — the **inbound** [`incident_bridge.py`](../../incident_bridge.py)
+(#612), which turns Sentry/GlitchTip *observations* into durable Gitea issues
+and `incident_links` rows.
+
+- Prefer **one** observability path per environment. Point the MCP server's
+  `SENTRY_DSN` at the same self-hosted `gitea-tools-mcp` project that the #612
+  bridge reconciles from, so an MCP-reported error and its Gitea issue line up.
+- GlitchTip is Sentry-protocol compatible; if an existing GlitchTip DSN is in
+  use, either migrate it to `https://sentry.prgs.cc/` or document the split
+  (MCP → Sentry, legacy → GlitchTip) explicitly for operators.
+- The bridge remains the **only** sanctioned route from an alert back into
+  Gitea workflow state.
+
+## 7. Non-goals
+
+- Sentry must **not** become the workflow source of truth.
+- Sentry must **not** approve, merge, close, or mutate Gitea workflow state.
+- Sentry must **not** bypass leases, #332, workflow roles, or the MCP gates.

gitea_mcp_server.py

@@ -653,6 +653,10 @@ def verify_preflight_purity(
             f"'{task}' (fail closed)"
         )
 
+    # #671: block review/merge/close/completion mutations while the session is
+    # contaminated by a direct stable-branch push attempt (reconciler-exempt).
+    _enforce_stable_branch_contamination_gate(task, remote)
+
     ctx = _resolve_namespace_mutation_context(worktree_path)
     workspace = ctx["workspace_path"]
     canonical_root = ctx["canonical_repo_root"]
@@ -724,6 +728,7 @@ def _verify_role_mutation_workspace(
     task: str | None = None,
 ) -> str:
     """Bind reviewer/merger mutations to the active namespace workspace (#510)."""
+
     # Check running runtimes to prevent stale mutations
     try:
         if "PYTEST_CURRENT_TEST" not in os.environ or "GITEA_FORCE_MCP_RUNTIME_CHECK" in os.environ:
@@ -809,6 +814,80 @@ def _enforce_root_checkout_guard(worktree_path: str | None = None) -> None:
         raise RuntimeError(root_checkout_guard.format_root_checkout_guard_error(assessment))
 
 
+# ── stable-branch push contamination (#671) ──────────────────────────────────
+# A worker session that attempts a direct stable-branch push (or a
+# root-checkout local commit) is workflow-contaminated. The marker is durable
+# (survives daemon process pools like the other session proofs) and keyed per
+# profile identity. It fails closed on gated mutations until a reconciler
+# audits and clears it.
+
+def _stable_contamination_profile_identity() -> str:
+    return mcp_session_state.current_profile_identity(
+        profile_name=get_profile().get("profile_name"),
+    )
+
+
+def _load_stable_contamination_marker(remote: str | None = None) -> dict | None:
+    return mcp_session_state.load_state(
+        kind=mcp_session_state.KIND_STABLE_BRANCH_CONTAMINATION,
+        remote=remote,
+        profile_identity=_stable_contamination_profile_identity(),
+    )
+
+
+def _save_stable_contamination_marker(
+    record: dict,
+    *,
+    remote: str | None = None,
+) -> dict | None:
+    return mcp_session_state.save_state(
+        kind=mcp_session_state.KIND_STABLE_BRANCH_CONTAMINATION,
+        payload=record,
+        remote=remote,
+        profile_identity=_stable_contamination_profile_identity(),
+    )
+
+
+def _clear_stable_contamination_marker(
+    *,
+    remote: str | None = None,
+    profile_identity: str | None = None,
+) -> None:
+    mcp_session_state.clear_state(
+        kind=mcp_session_state.KIND_STABLE_BRANCH_CONTAMINATION,
+        remote=remote,
+        profile_identity=profile_identity or _stable_contamination_profile_identity(),
+    )
+
+
+def _enforce_stable_branch_contamination_gate(
+    task: str | None,
+    remote: str | None = None,
+) -> None:
+    """#671 AC4: fail closed on gated mutations while contaminated.
+
+    Reconciler role is exempt (the sanctioned audit/clear path). Non-gated
+    tasks (comment_issue, lock_issue) stay allowed so a contaminated worker can
+    still post the durable audit comment and hand off.
+    """
+    if _preflight_in_test_mode() and not os.environ.get(
+        "GITEA_TEST_FORCE_STABLE_CONTAMINATION"
+    ):
+        return
+    marker = _load_stable_contamination_marker(remote)
+    if not marker:
+        return
+    gate = stable_branch_push_guard.assess_contamination_gate(
+        marker,
+        task=task,
+        actual_role=_actual_profile_role(),
+    )
+    if gate["block"]:
+        raise RuntimeError(
+            stable_branch_push_guard.format_contamination_gate_error(gate)
+        )
+
+
 from mcp.server.fastmcp import FastMCP  # noqa: E402
 
 from gitea_auth import (  # noqa: E402
@@ -839,6 +918,7 @@ import allocator_service  # noqa: E402
 import control_plane_db  # noqa: E402
 import lease_lifecycle  # noqa: E402
 import incident_bridge  # noqa: E402
+import sentry_observability  # noqa: E402  (#606 optional Sentry observability)
 import agent_temp_artifacts
 import issue_lock_worktree  # noqa: E402
 import issue_lock_provenance  # noqa: E402
@@ -849,6 +929,7 @@ import merge_approval_gate  # noqa: E402
 import already_landed_reconcile  # noqa: E402
 import author_mutation_worktree  # noqa: E402
 import root_checkout_guard  # noqa: E402
+import stable_branch_push_guard  # noqa: E402
 import remote_repo_guard  # noqa: E402
 import issue_claim_heartbeat  # noqa: E402
 import issue_work_duplicate_gate  # noqa: E402
@@ -1697,6 +1778,18 @@ def _audited(action: str, *, host, remote, org=None, repo=None,
                result=gitea_audit.FAILED, reason=_redact(str(exc)),
                request_metadata=request_metadata, issue_number=issue_number,
                pr_number=pr_number, target_branch=target_branch)
+        # #606: best-effort Sentry capture of the failing mutation (fail open).
+        sentry_observability.capture_exception(
+            exc,
+            tags={
+                "mutation_tool": action,
+                "remote": remote,
+                "repo": repo,
+                "org": org,
+                "issue_number": issue_number,
+                "pr_number": pr_number,
+            },
+        )
         raise
     _audit(action, host=host, remote=remote, org=org, repo=repo,
            result=gitea_audit.SUCCEEDED, request_metadata=request_metadata,
@@ -1743,6 +1836,20 @@ def _audit_pr_result(action: str):
                             "merge_method": result.get("merge_method"),
                         },
                     )
+                    # #606: surface fail-closed blockers / failed mutations to
+                    # Sentry as structured events (best-effort, fail open).
+                    if status in (gitea_audit.BLOCKED, gitea_audit.FAILED):
+                        sentry_observability.capture_workflow_blocker(
+                            action,
+                            message="; ".join(reasons) or action,
+                            next_action=result.get("safe_next_action"),
+                            level="error" if status == gitea_audit.FAILED else "warning",
+                            tags={
+                                "mutation_tool": action,
+                                "pr_number": result.get("pr_number"),
+                                "current_head_sha": result.get("head_sha"),
+                            },
+                        )
             except Exception:
                 pass  # best-effort; never break the tool
             return result
@@ -9273,6 +9380,160 @@ def gitea_diagnose_terminal(
     }
 
 
+@mcp.tool()
+def gitea_record_stable_branch_push_attempt(
+    command: str | None = None,
+    remote: str = "dadeschools",
+    ref: str | None = None,
+    session_id: str | None = None,
+    mark: bool = True,
+    current_branch: str | None = None,
+    head_sha: str | None = None,
+    remote_master_sha: str | None = None,
+    is_under_branches: bool | None = None,
+    ahead_count: int | None = None,
+) -> dict:
+    """Classify a proposed command for direct stable-branch push intent (#671).
+
+    Worker sessions must never publish stable branches (``master``/``main``/
+    ``dev``/...) directly. This tool detects ``git push <remote> master``
+    equivalents (refspecs, ``HEAD:master``, ``--force``, ``--dry-run`` no-op
+    intent, ``:master`` delete) and — separately — a root/control-checkout
+    local commit not carried by an issue feature branch.
+
+    When ``mark`` is true and contamination is detected, a durable
+    ``stable_branch_contamination`` marker is written for the active profile
+    identity. Subsequent review/merge/close/completion mutations then fail
+    closed (via the pre-flight gate) until a reconciler audits and clears it.
+    The stored command summary is redacted; secrets never persist.
+
+    Read-only when nothing is detected (or ``mark`` is false). Returns the
+    classification, any root-checkout assessment, and the marker state.
+    """
+    classification = stable_branch_push_guard.classify_push_command(command)
+
+    root_checkout = None
+    if any(v is not None for v in (current_branch, head_sha, remote_master_sha,
+                                   is_under_branches, ahead_count)):
+        root_checkout = stable_branch_push_guard.assess_root_checkout_local_commit(
+            current_branch=current_branch,
+            head_sha=head_sha,
+            remote_master_sha=remote_master_sha,
+            is_under_branches=bool(is_under_branches),
+            ahead_count=ahead_count,
+        )
+
+    push_contam = bool(classification.get("contamination"))
+    root_contam = bool(root_checkout and root_checkout.get("contamination"))
+    contaminated = push_contam or root_contam
+
+    marker = None
+    marked = False
+    if contaminated and mark:
+        if push_contam:
+            reason_class = "stable_branch_push"
+            command_redacted = classification.get("redacted_command")
+            detail = "; ".join(classification.get("reasons") or [])
+            resolved_ref = ref or (
+                (classification.get("stable_refs") or [None])[0]
+            )
+        else:
+            reason_class = "root_checkout_commit"
+            command_redacted = None
+            detail = "; ".join(root_checkout.get("reasons") or [])
+            resolved_ref = ref or root_checkout.get("current_branch")
+        record = stable_branch_push_guard.build_contamination_record(
+            reason_class=reason_class,
+            command_redacted=command_redacted,
+            session_id=session_id,
+            remote=remote,
+            ref=resolved_ref,
+            role=_actual_profile_role(),
+            detail=detail,
+        )
+        marker = _save_stable_contamination_marker(record, remote=remote)
+        marked = marker is not None
+
+    return {
+        "classification": classification,
+        "root_checkout": root_checkout,
+        "contaminated": contaminated,
+        "marked": marked,
+        "marker": marker,
+        "profile_identity": _stable_contamination_profile_identity(),
+        "remediation": stable_branch_push_guard.REMEDIATION if contaminated else None,
+    }
+
+
+@mcp.tool()
+def gitea_audit_stable_branch_contamination(
+    action: str = "inspect",
+    remote: str = "dadeschools",
+    profile_identity: str | None = None,
+) -> dict:
+    """Reconciler audit of a stable-branch contamination marker (#671).
+
+    ``action='inspect'`` (default, read-only) loads the durable marker for the
+    given ``profile_identity`` (or the active session's) and reports it.
+
+    ``action='clear'`` removes the marker so the contaminated session may
+    resume gated mutations. Clearing is the reconciler audit path and requires
+    an active reconciler profile — a worker session must never self-clear
+    (#671 security requirement). ``profile_identity`` targets the contaminated
+    worker's marker (a reconciler runs under its own identity).
+    """
+    act = (action or "inspect").strip().lower()
+    target_identity = (profile_identity or "").strip() or _stable_contamination_profile_identity()
+
+    marker = mcp_session_state.load_state(
+        kind=mcp_session_state.KIND_STABLE_BRANCH_CONTAMINATION,
+        remote=remote,
+        profile_identity=target_identity,
+    )
+
+    if act == "inspect":
+        return {
+            "action": "inspect",
+            "profile_identity": target_identity,
+            "contaminated": marker is not None,
+            "marker": marker,
+            "read_only": True,
+        }
+
+    if act == "clear":
+        role = _actual_profile_role()
+        if role != "reconciler":
+            return {
+                "action": "clear",
+                "success": False,
+                "performed": False,
+                "profile_identity": target_identity,
+                "reasons": [
+                    "stable-branch contamination may only be cleared by a "
+                    f"reconciler audit; active role is '{role}' (fail closed). "
+                    "The contaminated worker session must not self-clear."
+                ],
+            }
+        _clear_stable_contamination_marker(
+            remote=remote,
+            profile_identity=target_identity,
+        )
+        return {
+            "action": "clear",
+            "success": True,
+            "performed": True,
+            "profile_identity": target_identity,
+            "was_contaminated": marker is not None,
+        }
+
+    return {
+        "action": act,
+        "success": False,
+        "performed": False,
+        "reasons": [f"unknown action '{act}'; use 'inspect' or 'clear'"],
+    }
+
+
 @mcp.tool()
 def gitea_validate_review_final_report(
     report_text: str,
@@ -9720,6 +9981,11 @@ def gitea_assess_mcp_namespace_health(
         probe_source=probe_source,
     )
     _record_live_namespace_health(result)
+    # #606: namespace-health watchdog check-in (best-effort, fail open).
+    sentry_observability.monitor_checkin(
+        "namespace_health",
+        "ok" if result.get("healthy", result.get("callable", True)) else "error",
+    )
     return result
 
 
@@ -11647,6 +11913,18 @@ def gitea_allocate_next_work(
     result["inventory_source"] = (
         "candidates_json" if candidates_json else "gitea_live"
     )
+    # #606: watchdog check-ins for the recurring jobs this allocator run
+    # performs — global stale-lease expiry, terminal-lock lookup, and the
+    # allocator itself. Best-effort; a failed selection reports "error".
+    _alloc_ok = bool(result.get("success"))
+    sentry_observability.monitor_checkin(
+        "allocator_health", "ok" if _alloc_ok else "error"
+    )
+    if _alloc_ok:
+        # These two scans complete inside allocate_next_work before selection;
+        # a successful result proves both ran.
+        sentry_observability.monitor_checkin("stale_lease_scan", "ok")
+        sentry_observability.monitor_checkin("terminal_lock_scan", "ok")
     return result
 
 
@@ -11971,4 +12249,10 @@ if __name__ == "__main__":
     # processes (e.g. review_pr.py) can detect and refuse profile
     # side-channel overrides (#199).
     _export_session_profile_lock()
+    # #606: optional self-hosted Sentry observability. No-op unless
+    # MCP_SENTRY_ENABLED is truthy and SENTRY_DSN is set; never blocks startup.
+    _sentry_status = sentry_observability.init_sentry()
+    sys.stderr.write(
+        f"--- Sentry observability: {_sentry_status.get('reason')} ---\n"
+    )
     mcp.run(transport="stdio")

mcp_session_state.py

@@ -31,6 +31,11 @@ DEFAULT_TTL_HOURS = 4.0
 KIND_WORKFLOW_LOAD = "review_workflow_load"
 KIND_DECISION_LOCK = "review_decision_lock"
 KIND_REVIEW_DRAFT = "review_draft"
+# Durable marker set when a worker session attempts a direct stable-branch push
+# or a root-checkout local commit (#671). Keyed per profile identity like the
+# other session proofs; a contaminated session fails closed on gated mutations
+# until a reconciler audits and clears it.
+KIND_STABLE_BRANCH_CONTAMINATION = "stable_branch_contamination"
 
 
 

requirements.txt

@@ -31,6 +31,7 @@ python-multipart==0.0.32
 referencing==0.37.0
 rich==15.0.0
 rpds-py==2026.5.1
+sentry-sdk==2.20.0
 shellingham==1.5.4
 sse-starlette==3.4.5
 starlette==1.3.1

reviewer_worktree.py

@@ -27,6 +27,20 @@ _READONLY_REVIEWER_GIT = re.compile(
 _GIT_INVOCATION = re.compile(r"\bgit\b", re.IGNORECASE)
 
 
+# #673: Canonical pattern for identifying review worktrees under branches/.
+REVIEW_WORKTREE_RE = re.compile(
+    r"branches/(?:review-pr\d+[\w/-]*|merge-simulation-pr\d+|review-[\w-]+)",
+    re.IGNORECASE,
+)
+
+
+def is_review_worktree_path(path: str) -> bool:
+    """True when the path belongs to a reviewer or simulation worktree."""
+    normalized = (path or "").replace("\\", "/")
+    return bool(REVIEW_WORKTREE_RE.search(normalized))
+
+
+
 def parse_dirty_tracked_files(porcelain: str) -> list[str]:
     """Return tracked paths with local modifications from ``git status --porcelain``.
 

reviewer_worktree_ownership.py

@@ -5,10 +5,9 @@ from __future__ import annotations
 import re
 from typing import Any
 
-_SESSION_OWNED_RE = re.compile(
-    r"branches/(?:review-pr\d+[\w/-]*|review-[\w-]+)",
-    re.IGNORECASE,
-)
+from reviewer_worktree import REVIEW_WORKTREE_RE
+
+_SESSION_OWNED_RE = REVIEW_WORKTREE_RE
 _WORKTREE_PATH_RE = re.compile(
     r"(?:review worktree path|worktree path|session-owned worktree)\s*:\s*(\S+)",
     re.IGNORECASE,

sentry_observability.py

@@ -0,0 +1,535 @@
+"""Optional self-hosted Sentry observability for the Gitea MCP server (#606).
+
+Adds env-var-gated Sentry SDK instrumentation so runtime errors, fail-closed
+workflow blockers, lease/terminal-lock/stale-runtime collisions, and recurring
+watchdog check-ins are visible in a *self-hosted* Sentry at
+``https://sentry.prgs.cc/`` — never Sentry Cloud, and never as the workflow
+source of truth (Gitea stays canonical).
+
+Design constraints (mirror ``gitea_audit`` and the #612 incident bridge):
+
+- **Off by default.** With ``MCP_SENTRY_ENABLED`` false/unset *or* ``SENTRY_DSN``
+  empty, ``init_sentry`` is a no-op and no events are ever sent — existing tool
+  behaviour and API-call patterns are unchanged (acceptance criterion 1).
+- **Fail *open* for observability.** A Sentry outage, a missing ``sentry_sdk``
+  package, or any capture error must never break an MCP tool success path. Every
+  public entry point swallows its own exceptions.
+- **Fail *closed* for redaction.** If a field cannot be proven safe it is dropped
+  rather than sent. Tokens, passwords, keychain IDs, DSNs, private config, raw
+  session-state, full prompt bodies, and full filesystem paths never leave here.
+- **No hard dependency.** ``sentry_sdk`` is imported lazily; the module is fully
+  importable and testable without it installed.
+
+Sentry is observe-only: it must not approve, merge, close, or otherwise mutate
+Gitea workflow state, nor bypass leases, #332, or MCP gates. Alerts may only feed
+the sanctioned Gitea issue/comment path via the #612 incident bridge.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import os
+import re
+from dataclasses import dataclass
+from typing import Any
+
+# Reuse the most comprehensive existing scrubber so redaction stays consistent
+# with the #612 incident bridge (tokens, DSNs, cookies, bearer/basic, keychain
+# ids, session ids, user:pass@host).
+from incident_bridge import redact_text as _redact_text
+
+# Second, complementary scrubber: catches bare ``token <value>`` /
+# ``Bearer <value>`` / ``Basic <value>`` prefixes and raw URLs that the
+# incident-bridge delimiter patterns miss.
+from gitea_audit import _redact_str as _redact_prefixes
+
+# ── Optional SDK (lazy, never a hard dependency) ────────────────────────────
+try:  # pragma: no cover - trivial import guard
+    import sentry_sdk  # type: ignore
+except Exception:  # pragma: no cover - absence is a supported state
+    sentry_sdk = None  # type: ignore
+
+
+# ── Env var names (single source of truth) ──────────────────────────────────
+ENV_ENABLED = "MCP_SENTRY_ENABLED"
+ENV_DSN = "SENTRY_DSN"
+ENV_ENVIRONMENT = "SENTRY_ENVIRONMENT"
+ENV_RELEASE = "SENTRY_RELEASE"
+ENV_TRACES_SAMPLE_RATE = "MCP_SENTRY_TRACES_SAMPLE_RATE"
+ENV_ENABLE_LOGS = "MCP_SENTRY_ENABLE_LOGS"
+
+_TRUTHY = frozenset({"1", "true", "yes", "on"})
+
+REDACTED = "[REDACTED]"
+REDACTED_PATH = "[REDACTED_PATH]"
+
+
+# ── Cron / watchdog monitor slugs (acceptance criterion 6) ──────────────────
+# Stable slugs for the recurring/watchdog jobs #606 wants check-ins for. The
+# slug is the durable monitor identity in Sentry; the wiring call sites pass one
+# of these keys (or an explicit slug) to ``monitor_checkin``.
+MONITOR_SLUGS: dict[str, str] = {
+    "stale_lease_scan": "gitea-mcp-stale-lease-scan",
+    "terminal_lock_scan": "gitea-mcp-terminal-lock-scan",
+    "allocator_health": "gitea-mcp-allocator-health",
+    "namespace_health": "gitea-mcp-namespace-health",
+    "dashboard_freshness": "gitea-mcp-dashboard-freshness",
+    "reconciler_cleanup": "gitea-mcp-reconciler-cleanup",
+}
+
+_CHECKIN_STATUSES = frozenset({"in_progress", "ok", "error"})
+
+
+# ── Tag allowlist (issue "Suggested Sentry tags/context") ───────────────────
+# Only these keys are ever attached as Sentry tags. Anything else is dropped so
+# a caller cannot accidentally leak a sensitive value through a tag.
+ALLOWED_TAG_KEYS = frozenset({
+    "role",
+    "profile",
+    "namespace",
+    "repo",
+    "org",
+    "issue_number",
+    "pr_number",
+    "blocker_type",
+    "workflow_hash",
+    "session_id_hash",  # hash only — never the raw session id
+    "pid",
+    "worktree_category",  # category, never the full sensitive path
+    "lease_comment_id",
+    "expected_head_sha",
+    "current_head_sha",
+    "terminal_lock_state",
+    "capability",
+    "mutation_tool",
+})
+
+# Absolute-path shapes that must never be sent verbatim (macOS/Linux + temp).
+_PATH_RE = re.compile(r"(?:/private)?/(?:Users|home|tmp|var|opt|Volumes)/[^\s\"']*")
+
+# ``extra`` keys whose *full* contents are forbidden by the redaction rules
+# (raw session-state, full prompt/comment bodies, private config blobs, raw
+# headers).
+_FORBIDDEN_EXTRA_KEYS = frozenset({
+    "prompt",
+    "prompt_body",
+    "next_prompt",
+    "body",
+    "raw_body",
+    "session_state",
+    "session_state_contents",
+    "config",
+    "config_contents",
+    "private_config",
+    "headers",
+    "authorization",
+})
+
+
+# ── Configuration ───────────────────────────────────────────────────────────
+@dataclass(frozen=True)
+class SentryConfig:
+    """Immutable snapshot of the Sentry env configuration."""
+
+    enabled: bool = False
+    dsn: str | None = None
+    environment: str = "development"
+    release: str | None = None
+    traces_sample_rate: float = 0.0
+    enable_logs: bool = False
+
+    @property
+    def active(self) -> bool:
+        """True only when the operator both opted in *and* supplied a DSN.
+
+        This is the single gate that keeps the feature off by default: enabling
+        the flag without a DSN (or vice versa) sends nothing.
+        """
+        return bool(self.enabled and self.dsn)
+
+    def safe_summary(self) -> dict[str, Any]:
+        """Operator-facing status with **no** DSN value (only presence)."""
+        return {
+            "enabled": self.enabled,
+            "dsn_present": bool(self.dsn),
+            "environment": self.environment,
+            "release": self.release,
+            "traces_sample_rate": self.traces_sample_rate,
+            "enable_logs": self.enable_logs,
+            "active": self.active,
+        }
+
+
+def _env_bool(name: str, env: dict[str, str]) -> bool:
+    return (env.get(name) or "").strip().lower() in _TRUTHY
+
+
+def _env_float(name: str, default: float, env: dict[str, str]) -> float:
+    raw = (env.get(name) or "").strip()
+    if not raw:
+        return default
+    try:
+        val = float(raw)
+    except (TypeError, ValueError):
+        return default
+    # Clamp to Sentry's valid [0.0, 1.0] sample-rate range.
+    if val < 0.0:
+        return 0.0
+    if val > 1.0:
+        return 1.0
+    return val
+
+
+def load_config(env: dict[str, str] | None = None) -> SentryConfig:
+    """Build a :class:`SentryConfig` from the environment (read at call time)."""
+    env = dict(os.environ if env is None else env)
+    dsn = (env.get(ENV_DSN) or "").strip() or None
+    return SentryConfig(
+        enabled=_env_bool(ENV_ENABLED, env),
+        dsn=dsn,
+        environment=(env.get(ENV_ENVIRONMENT) or "").strip() or "development",
+        release=(env.get(ENV_RELEASE) or "").strip() or None,
+        traces_sample_rate=_env_float(ENV_TRACES_SAMPLE_RATE, 0.0, env),
+        enable_logs=_env_bool(ENV_ENABLE_LOGS, env),
+    )
+
+
+def sdk_available() -> bool:
+    """True when the optional ``sentry_sdk`` package is importable."""
+    return sentry_sdk is not None
+
+
+# ── Redaction (fail closed) ─────────────────────────────────────────────────
+def sanitize_path(value: Any) -> str:
+    """Reduce a filesystem path to a non-sensitive *category* token.
+
+    Full local paths must never be sent. We keep only a coarse worktree
+    category derived from the path shape (author/reviewer/merger/reconciler/
+    branches/root/other).
+    """
+    text = "" if value is None else str(value)
+    low = text.lower()
+    if not text:
+        return "unknown"
+    # Order matters: more specific role markers before the generic "branches".
+    if "reconcile" in low:
+        return "reconciler"
+    if "review" in low:
+        return "reviewer"
+    if "merge" in low or "merger" in low:
+        return "merger"
+    if "author" in low or re.search(r"/branches/(?:feat|fix|docs|chore|issue)", low):
+        return "author"
+    if "/branches/" in low:
+        return "branches"
+    if low.rstrip("/").endswith("gitea-tools"):
+        return "root"
+    return "other"
+
+
+def redact_value(value: Any) -> Any:
+    """Recursively redact a JSON-able value: secret text, absolute paths, and
+    known-sensitive dict keys are removed. Fail closed — any error drops the
+    value entirely rather than risk leaking it."""
+    try:
+        if isinstance(value, dict):
+            out: dict[str, Any] = {}
+            for k, v in value.items():
+                key = str(k)
+                low = key.lower()
+                if low in _FORBIDDEN_EXTRA_KEYS or any(
+                    s in low
+                    for s in ("token", "secret", "password", "cookie", "auth", "dsn", "keychain")
+                ):
+                    out[key] = REDACTED
+                    continue
+                out[key] = redact_value(v)
+            return out
+        if isinstance(value, (list, tuple)):
+            return [redact_value(v) for v in value]
+        if isinstance(value, str):
+            scrubbed = _redact_text(value)
+            scrubbed = _redact_prefixes(scrubbed)
+            scrubbed = _PATH_RE.sub(REDACTED_PATH, scrubbed)
+            return scrubbed
+        return value
+    except Exception:
+        return REDACTED
+
+
+def hash_session_id(session_id: Any) -> str:
+    """Short, stable, non-reversible fingerprint of a session id."""
+    digest = hashlib.sha256(str(session_id).encode("utf-8", "replace")).hexdigest()
+    return digest[:12]
+
+
+def build_tags(**kwargs: Any) -> dict[str, str]:
+    """Return a scrubbed, allowlisted tag dict.
+
+    ``session_id`` is accepted but only ever surfaced as ``session_id_hash``.
+    ``worktree_path`` collapses to ``worktree_category``. Any non-allowlisted
+    key, or a value that still contains redacted material after scrubbing, is
+    dropped.
+    """
+    raw: dict[str, Any] = dict(kwargs)
+
+    # Hash the session id — never emit it raw.
+    session_id = raw.pop("session_id", None)
+    if session_id and "session_id_hash" not in raw:
+        raw["session_id_hash"] = hash_session_id(session_id)
+
+    # A full worktree path collapses to a category tag.
+    wt = raw.pop("worktree_path", None)
+    if wt and "worktree_category" not in raw:
+        raw["worktree_category"] = sanitize_path(wt)
+
+    out: dict[str, str] = {}
+    for key, val in raw.items():
+        if key not in ALLOWED_TAG_KEYS:
+            continue
+        if val is None:
+            continue
+        scrubbed = redact_value(val)
+        text = str(scrubbed)
+        if not text or REDACTED in text or REDACTED_PATH in text:
+            continue
+        if len(text) > 200:
+            text = text[:200] + "…"
+        out[key] = text
+    return out
+
+
+def scrub_event(event: Any, hint: Any = None) -> dict[str, Any] | None:
+    """Sentry ``before_send`` / ``before_send_log`` hook.
+
+    Recursively redacts the outgoing event. On *any* failure it returns ``None``
+    so the event is dropped rather than sent unscrubbed (fail closed for
+    redaction).
+    """
+    try:
+        if not isinstance(event, dict):
+            return None
+        scrubbed = redact_value(event)
+        # Drop server_name if it leaked a hostname/path; PID is kept via tags.
+        scrubbed.pop("server_name", None)
+        return scrubbed
+    except Exception:
+        return None
+
+
+# ── Event builders (pure, independently testable) ───────────────────────────
+def build_blocker_event(
+    blocker_type: str,
+    *,
+    message: str | None = None,
+    next_action: str | None = None,
+    level: str = "warning",
+    tags: dict[str, Any] | None = None,
+    extra: dict[str, Any] | None = None,
+) -> dict[str, Any]:
+    """Build a redacted, structured Sentry event for a workflow blocker.
+
+    ``next_action`` maps the issue's "canonical next action when available"
+    requirement (acceptance criterion 7).
+    """
+    merged_tags = dict(tags or {})
+    merged_tags.setdefault("blocker_type", blocker_type)
+    safe_tags = build_tags(**merged_tags)
+
+    safe_extra = redact_value(dict(extra or {}))
+    if next_action:
+        # A short canonical next action is allowed (it is not a full prompt).
+        safe_extra["canonical_next_action"] = redact_value(str(next_action)[:500])
+
+    event: dict[str, Any] = {
+        "message": redact_value(message or blocker_type),
+        "level": level if level in ("debug", "info", "warning", "error", "fatal") else "warning",
+        "logger": "gitea-mcp.workflow",
+        "tags": safe_tags,
+        "extra": safe_extra,
+        "fingerprint": ["workflow-blocker", blocker_type],
+    }
+    return event
+
+
+def build_checkin_payload(
+    monitor: str,
+    status: str,
+    *,
+    check_in_id: str | None = None,
+    duration: float | None = None,
+) -> dict[str, Any]:
+    """Build a Sentry cron check-in payload for one of :data:`MONITOR_SLUGS`.
+
+    ``monitor`` may be a registry key (e.g. ``"stale_lease_scan"``) or an
+    explicit slug. Raises ``ValueError`` on an unknown status so callers cannot
+    silently send a malformed check-in.
+    """
+    if status not in _CHECKIN_STATUSES:
+        raise ValueError(
+            f"invalid check-in status {status!r}; expected one of {sorted(_CHECKIN_STATUSES)}"
+        )
+    slug = MONITOR_SLUGS.get(monitor, monitor)
+    payload: dict[str, Any] = {"monitor_slug": slug, "status": status}
+    if check_in_id:
+        payload["check_in_id"] = str(check_in_id)
+    if duration is not None:
+        try:
+            payload["duration"] = float(duration)
+        except (TypeError, ValueError):
+            pass
+    return payload
+
+
+# ── Runtime init + capture (fail open) ──────────────────────────────────────
+_STATE: dict[str, Any] = {"initialized": False, "config": None}
+
+
+def is_initialized() -> bool:
+    return bool(_STATE.get("initialized"))
+
+
+def active_config() -> SentryConfig | None:
+    return _STATE.get("config")
+
+
+def reset_for_tests() -> None:
+    """Clear module init state. Test-only helper (never called in production)."""
+    _STATE["initialized"] = False
+    _STATE["config"] = None
+
+
+def init_sentry(config: SentryConfig | None = None) -> dict[str, Any]:
+    """Initialise the Sentry SDK if (and only if) enabled + DSN + SDK present.
+
+    Idempotent and never raises. Returns an operator-safe status dict (no DSN
+    value). Behaviour is unchanged when the feature is off.
+    """
+    cfg = config or load_config()
+    status: dict[str, Any] = {"initialized": False, **cfg.safe_summary()}
+    try:
+        if not cfg.active:
+            status["reason"] = "disabled (MCP_SENTRY_ENABLED false or SENTRY_DSN empty)"
+            _STATE["config"] = cfg
+            return status
+        if not sdk_available():
+            status["reason"] = "sentry_sdk not installed"
+            _STATE["config"] = cfg
+            return status
+
+        init_kwargs: dict[str, Any] = {
+            "dsn": cfg.dsn,
+            "environment": cfg.environment,
+            "release": cfg.release,
+            "traces_sample_rate": cfg.traces_sample_rate,
+            "before_send": scrub_event,
+            "send_default_pii": False,
+        }
+        if cfg.enable_logs:
+            # sentry-sdk 2.x captures Python logs as structured logs when the
+            # experimental logs feature is enabled; scrub those too.
+            init_kwargs["_experiments"] = {
+                "enable_logs": True,
+                "before_send_log": scrub_event,
+            }
+        sentry_sdk.init(**init_kwargs)  # type: ignore[union-attr]
+        _STATE["initialized"] = True
+        _STATE["config"] = cfg
+        status["initialized"] = True
+        status["reason"] = "sentry initialised"
+    except Exception as exc:  # fail open: observability must not block startup
+        status["reason"] = f"init failed (ignored): {type(exc).__name__}"
+        _STATE["initialized"] = False
+    return status
+
+
+def _set_scope_tags(scope: Any, tags: dict[str, str]) -> None:
+    for key, val in tags.items():
+        try:
+            scope.set_tag(key, val)
+        except Exception:
+            pass
+
+
+def capture_workflow_blocker(
+    blocker_type: str,
+    *,
+    message: str | None = None,
+    next_action: str | None = None,
+    level: str = "warning",
+    tags: dict[str, Any] | None = None,
+    extra: dict[str, Any] | None = None,
+) -> dict[str, Any]:
+    """Capture a fail-closed workflow blocker as a structured Sentry event.
+
+    Always returns the redacted event dict (so callers/tests can inspect it),
+    and sends it to Sentry only when initialised. Fail open.
+    """
+    event = build_blocker_event(
+        blocker_type,
+        message=message,
+        next_action=next_action,
+        level=level,
+        tags=tags,
+        extra=extra,
+    )
+    try:
+        if is_initialized() and sdk_available():
+            sentry_sdk.capture_event(event)  # type: ignore[union-attr]
+    except Exception:
+        pass
+    return event
+
+
+def capture_exception(
+    exc: BaseException,
+    *,
+    tags: dict[str, Any] | None = None,
+    extra: dict[str, Any] | None = None,
+) -> bool:
+    """Capture a runtime exception with scrubbed tags. Fail open.
+
+    Returns True only when the event was handed to an initialised SDK.
+    """
+    try:
+        if not (is_initialized() and sdk_available()):
+            return False
+        safe_tags = build_tags(**(tags or {}))
+        safe_extra = redact_value(dict(extra or {}))
+        with sentry_sdk.push_scope() as scope:  # type: ignore[union-attr]
+            _set_scope_tags(scope, safe_tags)
+            for key, val in safe_extra.items():
+                try:
+                    scope.set_extra(key, val)
+                except Exception:
+                    pass
+            sentry_sdk.capture_exception(exc)  # type: ignore[union-attr]
+        return True
+    except Exception:
+        return False
+
+
+def monitor_checkin(
+    monitor: str,
+    status: str,
+    *,
+    check_in_id: str | None = None,
+    duration: float | None = None,
+) -> dict[str, Any] | None:
+    """Send a Sentry cron check-in for a watchdog job. Fail open.
+
+    Returns the payload (for inspection/tests), or ``None`` if the status was
+    invalid. Only transmits when initialised.
+    """
+    try:
+        payload = build_checkin_payload(
+            monitor, status, check_in_id=check_in_id, duration=duration
+        )
+    except ValueError:
+        return None
+    try:
+        if is_initialized() and sdk_available() and hasattr(sentry_sdk, "capture_checkin"):
+            sentry_sdk.capture_checkin(**payload)  # type: ignore[union-attr]
+    except Exception:
+        pass
+    return payload

skills/llm-project-workflow/SKILL.md

@@ -32,6 +32,15 @@ workflow file.
   mutation.
 - A nearby capability does not count.
 - Do not self-review or self-merge.
+- **Never push a stable branch directly.** Worker sessions (author/reviewer/merger)
+  must never run `git push <remote> master` — or `main`/`dev`/other stable refs,
+  including refspecs (`HEAD:master`), `--force`, `--delete`, or `--dry-run` no-op
+  probes — and must never commit on the root/control checkout outside an issue
+  feature branch. Stable-branch updates land ONLY through sanctioned Gitea merge
+  tooling (`gitea_merge_pr`) or an explicitly authorized reconciler path. A
+  detected attempt marks the session workflow-contaminated (#671) and fails
+  closed on review/merge/close/completion until a reconciler audits and clears
+  it. `git fetch` / `git pull --ff-only` and feature-branch pushes stay allowed.
 - Do not mix modes in one run.
 - **BLOCKED + DIAGNOSE default rule (required):** If any required workflow step, skill, tool, capability, preflight, instruction, profile, worktree binding, or terminal/MCP operation cannot be performed or loaded (including the canonical ones listed in this skill and its loaded workflow), immediately enter `BLOCKED + DIAGNOSE`. Stop before any git or Gitea mutation. Diagnose using the standard template in [`templates/blocked-diagnose-report.md`](templates/blocked-diagnose-report.md). Attempt *only* safe non-mutating recovery. Report using the template. Do not continue, use fallbacks, or treat the missing requirement as harmless.
 - If the required workflow cannot be loaded, stop and produce a recovery handoff
@@ -48,6 +57,11 @@ workflow file.
 - wrong profile or role for the requested operation
 - dirty or misbound worktree (root checkout or non-branches/ path)
 - root checkout mutation risk
+- stable-branch push contamination (#671): a direct `git push <remote> master`
+  (or `main`/`dev`) equivalent, or a root/control-checkout commit not on an issue
+  feature branch, marks the session workflow-contaminated; review/merge/close/
+  completion mutations then fail closed until a reconciler audits and clears it
+  (`gitea_audit_stable_branch_contamination action=clear`, reconciler-only)
 - mutation guard failure (e.g. branches-only guard)
 - missing required MCP tool/schema or operation
 - stale or inconsistent runtime state (e.g. lease vs actual, dirty state disagreement)
@@ -118,6 +132,42 @@ The main project checkout is a stable control checkout on `master`, `main`, or
 If `cwd` is not inside `branches/`, stop before any file edit, test write,
 commit, merge, rebase, or cleanup. The main checkout is orchestration-only.
 
+## Stable Branch Push Protection (#671)
+
+Worker sessions must **never** publish a stable branch directly. This is the
+prevention hardening for the #670 incident (a bare direct-to-master commit
+`2fa97c26` and a PR #654 merger `git push prgs master` attempt).
+
+**Forbidden for author/reviewer/merger sessions:**
+
+- `git push <remote> master` (and `main`, `dev`, `develop`, `development`),
+  including refspecs (`HEAD:master`, `+refs/heads/x:refs/heads/master`),
+  `--force`, `--delete` / `:master`, and `--dry-run`/`-n` no-op probes (a
+  dry-run still proves intent and contaminates the session).
+- Local commits on the root/control checkout that are not carried by an issue
+  feature branch under `branches/`.
+
+**Allowed (never blocked):**
+
+- `git fetch` and `git pull --ff-only` of master into the control checkout when
+  authorized for sync.
+- Feature-branch pushes to non-stable refs (`git push <remote> fix/issue-N-...`).
+- Sanctioned merges via `gitea_merge_pr` / the Gitea API merge endpoint — the
+  **only** way stable branches advance.
+
+**What happens on a detected attempt:** the session is marked
+workflow-contaminated (durable `stable_branch_contamination` marker, redacted
+command summary + session id + remote + ref). While contaminated, all
+review / merge / close / issue-completion mutations fail closed. `comment_issue`
+and `lock_issue` remain allowed so the contaminated worker can post the durable
+audit comment and hand off. Contamination **cannot be self-cleared** — only a
+reconciler audit (`gitea_audit_stable_branch_contamination action=clear`) may
+clear it.
+
+Tooling: call `gitea_record_stable_branch_push_attempt` to classify/record a
+proposed push before running it; `gitea_audit_stable_branch_contamination` to
+inspect or (reconciler-only) clear the marker.
+
 ## Shell Spawn Hard-Stop Rule
 
 `exit_code: -1` with empty stdout/stderr means the shell failed to spawn — not a

stable_branch_push_guard.py

@@ -0,0 +1,478 @@
+"""Fail-closed guard against direct pushes to stable branches (#671).
+
+MCP workflow sessions must never publish to a stable branch (``master``,
+``main``, ``dev``, ...) directly. Stable-branch updates land only through
+sanctioned Gitea merge tooling or an explicitly authorized reconciler path.
+
+Incident origin (#670): a bare direct-to-master commit ``2fa97c26`` landed on
+``prgs/master`` without PR/review provenance, and a PR #654 merger run
+attempted ``git push prgs master`` (audited as a no-op, but the *intent* is the
+hazard). Partial protections already existed (``author_proofs.PROTECTED_BRANCHES``,
+``root_checkout_guard``, branch-push proofs) but did not detect shell push
+equivalents, mark the session contaminated after such an attempt, or fail
+closed on subsequent review/merge/close/completion mutations.
+
+This module is the detection + contamination-policy core. Like
+``author_proofs`` and ``root_checkout_guard`` it is **pure**: callers gather
+the raw facts (the proposed command line, git state, the durable contamination
+marker) and pass them in, so the same logic serves prompts, MCP gates, and
+tests. Nothing here performs git or network calls or reads durable state; the
+server wires these helpers to ``mcp_session_state`` and ``verify_preflight_purity``.
+
+Design rules honoured (from the #671 acceptance criteria):
+
+* Detect ``git push <remote> master`` shell equivalents, including refspecs
+  (``HEAD:master``, ``+refs/heads/x:refs/heads/master``), ``--force``,
+  ``--dry-run``/no-op intent, and delete refspecs (``:master``).
+* Never false-block a feature-branch push (``git push prgs fix/issue-671-...``).
+* Never treat ``git fetch`` / ``git pull --ff-only`` as a push.
+* Never treat sanctioned ``gitea_merge_pr`` / Gitea API merge as a push.
+* Fail closed on ambiguous targets that *may* resolve to a stable branch, but
+  surface ambiguity as its own signal rather than silently blocking feature work.
+* Contamination must not be clearable by the same worker session — only a
+  reconciler (audit) role may clear or bypass the gate.
+"""
+
+from __future__ import annotations
+
+import re
+from typing import Any, Iterable
+
+from author_proofs import PROTECTED_BRANCHES
+
+# Single source of truth for the stable branch set: the same protected set the
+# author branch-identity proofs already enforce (#177), so the two guards can
+# never drift apart.
+STABLE_BRANCHES = PROTECTED_BRANCHES
+
+# Mutations that must fail closed once the session is contaminated by a direct
+# stable-branch push attempt (#671 AC4: review, merge, close, completion).
+# ``comment_issue`` / ``lock_issue`` / ``create_issue`` are deliberately NOT
+# gated so a contaminated worker can still post the durable audit comment and
+# hand off. Only a reconciler (audit) role bypasses this set.
+CONTAMINATION_GATED_TASKS = frozenset({
+    "create_pr",
+    "commit_files",
+    "gitea_commit_files",
+    "close_pr",
+    "close_issue",
+    "review_pr",
+    "approve_pr",
+    "request_changes_pr",
+    "submit_pr_review",
+    "merge_pr",
+    "delete_branch",
+    "complete_issue",
+})
+
+CONTAMINATION_KIND = "stable_branch_push"
+
+REMEDIATION = (
+    "Direct stable-branch publication is forbidden for worker sessions. Stop, "
+    "leave the stable branch untouched, and route the change through sanctioned "
+    "Gitea merge tooling (gitea_merge_pr) or an explicitly authorized reconciler "
+    "audit. This session is workflow-contaminated until a reconciler audits it."
+)
+
+# ── command tokenising ────────────────────────────────────────────────────────
+
+# Split a compound command line into individual simple commands on shell
+# separators so ``a && git push prgs master`` is analysed segment by segment.
+_SEGMENT_SPLIT_RE = re.compile(r"(?:\|\||&&|\||;|\n)")
+
+_GIT_PUSH_RE = re.compile(r"\bgit\b[\w\s\-]*?\bpush\b", re.IGNORECASE)
+_GIT_FETCH_RE = re.compile(r"\bgit\b[\w\s\-]*?\b(?:fetch|pull)\b", re.IGNORECASE)
+
+# Flags that take a value argument in ``git push`` (so the following token is
+# consumed as the flag's value, not a refspec).
+_VALUE_FLAGS = frozenset({
+    "--repo",
+    "-o",
+    "--push-option",
+    "--receive-pack",
+    "--exec",
+})
+
+_FORCE_FLAGS = frozenset({"-f", "--force"})
+_DRY_RUN_FLAGS = frozenset({"-n", "--dry-run"})
+_DELETE_FLAGS = frozenset({"-d", "--delete"})
+
+
+def _clean(value: str | None) -> str:
+    return (value or "").strip()
+
+
+def _strip_ref_prefix(ref: str) -> str:
+    ref = ref.strip()
+    for prefix in ("refs/heads/", "heads/"):
+        if ref.startswith(prefix):
+            return ref[len(prefix):]
+    return ref
+
+
+def is_stable_ref(ref: str | None) -> bool:
+    """True when ``ref`` names a configured stable branch."""
+    name = _strip_ref_prefix(_clean(ref))
+    return bool(name) and name in STABLE_BRANCHES
+
+
+# ── redaction ─────────────────────────────────────────────────────────────────
+
+_URL_USERINFO_RE = re.compile(r"(https?://)[^/\s:@]+(?::[^/\s@]+)?@", re.IGNORECASE)
+_SECRET_ASSIGN_RE = re.compile(
+    r"\b((?:GITEA_)?(?:TOKEN|PASSWORD|PASS|PAT|SECRET|API_KEY|AUTH))\s*=\s*\S+",
+    re.IGNORECASE,
+)
+_BEARER_RE = re.compile(r"\b(Bearer|token)\s+[A-Za-z0-9._\-]{8,}", re.IGNORECASE)
+
+
+def redact_command(command: str | None) -> str:
+    """Strip credentials/URLs from a command line before logging it (#671).
+
+    Redacts URL userinfo (``https://user:tok@host`` → ``https://***@host``),
+    ``TOKEN=...`` style assignments, and bearer/token headers. Leaves the
+    structural parts (``git push <remote> master``) intact for audit value.
+    """
+    text = _clean(command)
+    if not text:
+        return ""
+    text = _URL_USERINFO_RE.sub(r"\1***@", text)
+    text = _SECRET_ASSIGN_RE.sub(lambda m: f"{m.group(1)}=***", text)
+    text = _BEARER_RE.sub(lambda m: f"{m.group(1)} ***", text)
+    return text
+
+
+# ── push classification ───────────────────────────────────────────────────────
+
+def _analyse_push_segment(segment: str) -> dict[str, Any]:
+    """Classify one ``git push ...`` command segment."""
+    tokens = segment.split()
+    # Drop everything up to and including the ``push`` verb.
+    try:
+        push_idx = next(
+            i for i, tok in enumerate(tokens)
+            if tok.lower() == "push"
+        )
+    except StopIteration:
+        push_idx = -1
+    args = tokens[push_idx + 1:] if push_idx >= 0 else []
+
+    is_force = False
+    is_dry_run = False
+    is_delete = False
+    positionals: list[str] = []
+
+    skip_next = False
+    for tok in args:
+        if skip_next:
+            skip_next = False
+            continue
+        if tok in _FORCE_FLAGS or tok.startswith("--force-with-lease") or tok.startswith("--force-if-includes"):
+            is_force = True
+            continue
+        if tok in _DRY_RUN_FLAGS:
+            is_dry_run = True
+            continue
+        if tok in _DELETE_FLAGS:
+            is_delete = True
+            continue
+        if tok in _VALUE_FLAGS:
+            skip_next = True
+            continue
+        if tok.startswith("--") and "=" in tok:
+            # e.g. --repo=... : self-contained, not a refspec.
+            continue
+        if tok.startswith("-"):
+            # Unknown/combined short flag; ignore for ref detection.
+            continue
+        positionals.append(tok)
+
+    # First positional after push is the remote (when any positional exists);
+    # the rest are refspecs / branch names.
+    remote = positionals[0] if positionals else None
+    refspecs = positionals[1:]
+
+    stable_refs: list[str] = []
+    force_to_stable = False
+    delete_stable = False
+    for spec in refspecs:
+        force_spec = spec.startswith("+")
+        body = spec[1:] if force_spec else spec
+        if ":" in body:
+            src, _, dst = body.partition(":")
+            dest = dst
+            if src == "" and dst:
+                # ``:master`` — delete refspec.
+                is_delete = True
+        else:
+            dest = body
+        if is_stable_ref(dest):
+            stable_refs.append(_strip_ref_prefix(dest))
+            if force_spec or is_force:
+                force_to_stable = True
+            if is_delete:
+                delete_stable = True
+
+    targets_stable = bool(stable_refs)
+    # Ambiguous: ``git push <remote>`` (or bare ``git push``) with no refspec —
+    # resolves to the current branch's upstream, which we cannot see from the
+    # command alone. Flag it, but do not assert stable (would false-block
+    # feature-branch pushes).
+    ambiguous = not refspecs
+
+    return {
+        "is_git_push": True,
+        "remote": remote,
+        "refspecs": refspecs,
+        "targets_stable": targets_stable,
+        "stable_refs": stable_refs,
+        "is_force": is_force or force_to_stable,
+        "is_dry_run": is_dry_run,
+        "is_delete": is_delete or delete_stable,
+        "ambiguous_target": ambiguous,
+    }
+
+
+def classify_push_command(command: str | None) -> dict[str, Any]:
+    """Classify a shell command line for direct stable-branch push intent (#671).
+
+    Returns a dict describing whether the command is a ``git push`` targeting a
+    stable branch. Fetch/pull are never pushes. A sanctioned Gitea merge (which
+    is not a ``git push`` at all) classifies as non-push. Dry-run and no-op
+    pushes still count as *intent* and are reported as contamination
+    (``proves_intent``) so a ``--dry-run`` cannot be used to probe the gate.
+    """
+    text = _clean(command)
+    result: dict[str, Any] = {
+        "command": text,
+        "redacted_command": redact_command(text),
+        "is_git_push": False,
+        "is_fetch_or_pull": False,
+        "targets_stable": False,
+        "stable_refs": [],
+        "is_force": False,
+        "is_dry_run": False,
+        "is_delete": False,
+        "ambiguous_target": False,
+        "contamination": False,
+        "proves_intent": False,
+        "reasons": [],
+    }
+    if not text:
+        return result
+
+    stable_refs: list[str] = []
+    saw_push = False
+    for segment in _SEGMENT_SPLIT_RE.split(text):
+        seg = segment.strip()
+        if not seg:
+            continue
+        if _GIT_FETCH_RE.search(seg) and not _GIT_PUSH_RE.search(seg):
+            result["is_fetch_or_pull"] = True
+            continue
+        if not _GIT_PUSH_RE.search(seg):
+            continue
+        saw_push = True
+        analysis = _analyse_push_segment(seg)
+        result["is_git_push"] = True
+        result["is_force"] = result["is_force"] or analysis["is_force"]
+        result["is_dry_run"] = result["is_dry_run"] or analysis["is_dry_run"]
+        result["is_delete"] = result["is_delete"] or analysis["is_delete"]
+        result["ambiguous_target"] = result["ambiguous_target"] or analysis["ambiguous_target"]
+        stable_refs.extend(analysis["stable_refs"])
+
+    result["stable_refs"] = sorted(set(stable_refs))
+    result["targets_stable"] = bool(stable_refs)
+
+    reasons: list[str] = []
+    if result["targets_stable"]:
+        refs = ", ".join(result["stable_refs"])
+        verb = "delete" if result["is_delete"] else ("force-push" if result["is_force"] else "push")
+        qualifier = " (dry-run/no-op still proves intent)" if result["is_dry_run"] else ""
+        reasons.append(
+            f"direct stable-branch {verb} detected targeting: {refs}{qualifier}; "
+            "worker sessions must never publish stable branches directly"
+        )
+        result["contamination"] = True
+        result["proves_intent"] = True
+    elif saw_push and result["ambiguous_target"]:
+        # Bare ``git push`` with no refspec: ambiguous. Report, but do not
+        # contaminate on the command alone — the root-checkout / branch-state
+        # detector resolves whether the current branch is stable.
+        reasons.append(
+            "ambiguous 'git push' with no refspec: resolve the current branch "
+            "before pushing; if it is a stable branch this is forbidden"
+        )
+
+    result["reasons"] = reasons
+    return result
+
+
+def detect_stable_push(commands: str | Iterable[str] | None) -> dict[str, Any]:
+    """Classify one command or an iterable of commands; contamination if any hit."""
+    if commands is None:
+        return classify_push_command(None)
+    if isinstance(commands, str):
+        return classify_push_command(commands)
+    worst: dict[str, Any] | None = None
+    for cmd in commands:
+        res = classify_push_command(cmd)
+        if res["contamination"]:
+            return res
+        if worst is None or (res["is_git_push"] and not worst["is_git_push"]):
+            worst = res
+    return worst or classify_push_command(None)
+
+
+# ── root/control checkout local-commit detection ──────────────────────────────
+
+def assess_root_checkout_local_commit(
+    *,
+    current_branch: str | None,
+    head_sha: str | None,
+    remote_master_sha: str | None,
+    is_under_branches: bool,
+    ahead_count: int | None = None,
+) -> dict[str, Any]:
+    """Detect a local commit on the root/control checkout not on a feature branch.
+
+    #671 AC2. An isolated ``branches/...`` worktree is exempt (that is where
+    feature work belongs). On the control checkout, a commit is illegitimate
+    when the checkout sits on a stable branch (or detached) and its HEAD has
+    advanced past the tracking ``prgs/master`` — i.e. a commit was made that is
+    not carried by an issue feature branch/PR.
+
+    Positive evidence only: missing state reports ``unknown`` rather than
+    asserting contamination, but an unreadable *branch* on the control checkout
+    (detached HEAD) with an advanced HEAD is still flagged.
+    """
+    branch = _clean(current_branch)
+    head = _clean(head_sha).lower()
+    master = _clean(remote_master_sha).lower()
+
+    if is_under_branches:
+        return {
+            "contamination": False,
+            "unknown": False,
+            "reasons": [],
+            "detail": "isolated branches/ worktree — feature commits are expected here",
+        }
+
+    reasons: list[str] = []
+    unknown = False
+
+    on_stable = (not branch) or (branch in STABLE_BRANCHES)
+    if not on_stable:
+        # Control checkout is on some non-stable branch: out of scope for this
+        # detector (root_checkout_guard #475 handles that contamination class).
+        return {
+            "contamination": False,
+            "unknown": False,
+            "reasons": [],
+            "detail": f"control checkout on non-stable branch '{branch}' — not this detector's class",
+        }
+
+    advanced = False
+    if ahead_count is not None and ahead_count > 0:
+        advanced = True
+    if head and master and head != master:
+        advanced = True
+    if (not head or not master) and ahead_count is None:
+        unknown = True
+
+    if advanced:
+        where = f"branch '{branch}'" if branch else "detached HEAD"
+        reasons.append(
+            f"control checkout ({where}) has local commits not on an issue "
+            "feature branch (HEAD advanced past prgs/master); worker sessions "
+            "must commit only on issue branches under branches/"
+        )
+
+    return {
+        "contamination": bool(reasons),
+        "unknown": unknown and not reasons,
+        "reasons": reasons,
+        "current_branch": branch or None,
+        "head_sha": head or None,
+        "remote_master_sha": master or None,
+    }
+
+
+# ── contamination record + gate ───────────────────────────────────────────────
+
+def build_contamination_record(
+    *,
+    reason_class: str,
+    command_redacted: str | None = None,
+    session_id: str | None = None,
+    remote: str | None = None,
+    ref: str | None = None,
+    role: str | None = None,
+    detail: str | None = None,
+) -> dict[str, Any]:
+    """Build the durable contamination marker payload (redacted, audit-safe).
+
+    ``reason_class`` is one of ``stable_branch_push`` / ``root_checkout_commit``.
+    The command is stored already-redacted; callers pass the raw line through
+    :func:`redact_command` (or this builder redacts a raw ``command`` for them).
+    """
+    return {
+        "kind": CONTAMINATION_KIND,
+        "reason_class": _clean(reason_class) or "stable_branch_push",
+        "command_summary": redact_command(command_redacted),
+        "session_id": _clean(session_id) or None,
+        "remote": _clean(remote) or None,
+        "ref": _clean(ref) or None,
+        "role": _clean(role) or None,
+        "detail": _clean(detail) or None,
+        "cleared_by_reconciler": False,
+    }
+
+
+def assess_contamination_gate(
+    marker: dict[str, Any] | None,
+    *,
+    task: str | None,
+    actual_role: str | None,
+) -> dict[str, Any]:
+    """Fail closed on gated mutations while a contamination marker is live (#671 AC4).
+
+    * No marker → allowed.
+    * Reconciler (audit) role → allowed (the sanctioned path to inspect/clear).
+    * Marker present + ``task`` in :data:`CONTAMINATION_GATED_TASKS` → blocked.
+    * Marker present + non-gated task (e.g. ``comment_issue``) → allowed, so the
+      worker can still post the durable audit/handoff comment.
+    """
+    if not marker or marker.get("cleared_by_reconciler"):
+        return {"block": False, "reasons": [], "task": task}
+
+    role = _clean(actual_role).lower()
+    if role == "reconciler":
+        return {
+            "block": False,
+            "reasons": [],
+            "task": task,
+            "detail": "reconciler audit path is exempt from the contamination gate",
+        }
+
+    task_name = _clean(task)
+    if task_name and task_name in CONTAMINATION_GATED_TASKS:
+        summary = marker.get("command_summary") or marker.get("detail") or "(no summary)"
+        reason_class = marker.get("reason_class") or "stable_branch_push"
+        return {
+            "block": True,
+            "reasons": [
+                f"session is workflow-contaminated ({reason_class}): {summary}. "
+                f"'{task_name}' is blocked until a reconciler audits and clears "
+                "the contamination. " + REMEDIATION
+            ],
+            "task": task_name,
+        }
+
+    return {"block": False, "reasons": [], "task": task_name or None}
+
+
+def format_contamination_gate_error(gate: dict[str, Any]) -> str:
+    """Single RuntimeError message for MCP mutation gates."""
+    reasons = "; ".join(gate.get("reasons") or ["session workflow-contaminated"])
+    return f"Stable-branch contamination gate (#671): {reasons}"

tests/conftest.py

@@ -26,7 +26,16 @@ def _reset_mutation_authority(monkeypatch):
     Pin ``default_state_dir`` / ``DEFAULT_STATE_DIR`` to a per-test temp dir
     so durable load/save never touches host state even after env clears.
     """
-    monkeypatch.delenv("GITEA_SESSION_PROFILE_LOCK", raising=False)
+    for env_key in [
+        "GITEA_SESSION_PROFILE_LOCK",
+        "GITEA_ACTIVE_WORKTREE",
+        "GITEA_AUTHOR_WORKTREE",
+        "GITEA_REVIEWER_WORKTREE",
+        "GITEA_MERGER_WORKTREE",
+        "GITEA_RECONCILER_WORKTREE",
+    ]:
+        monkeypatch.delenv(env_key, raising=False)
+
     # Isolate durable session-state files so tests never share host cache (#559).
     import tempfile
 

tests/test_root_checkout_guard.py

@@ -141,13 +141,21 @@ class TestVerifyPreflightRootGuardIntegration(unittest.TestCase):
         self.assertIn("Root checkout guard (#475)", str(ctx.exception))
         self.assertIn(rcg.REMEDIATION, str(ctx.exception))
 
+    @patch("os.path.isdir", return_value=True)
+    @patch("os.path.exists", return_value=True)
+    @patch("subprocess.run")
     @patch("gitea_mcp_server._get_workspace_porcelain", return_value="")
     @patch("gitea_mcp_server.root_checkout_guard.resolve_remote_master_sha", return_value=MASTER_SHA)
     @patch("gitea_mcp_server.issue_lock_worktree.read_worktree_git_state")
     @patch("gitea_mcp_server._resolve_author_mutation_context")
     def test_reviewer_from_branches_worktree_allowed(
-        self, mock_ctx, mock_git, _remote_sha, _porcelain,
+        self, mock_ctx, mock_git, _remote_sha, _porcelain, mock_run, _exists, _isdir,
     ):
+        import unittest.mock
+        mock_run.return_value = unittest.mock.MagicMock(
+            returncode=0,
+            stdout=f"{CONTROL_ROOT}/.git\n",
+        )
         srv._preflight_capability_baseline_porcelain = ""
         mock_ctx.return_value = {
             "workspace_path": BRANCHES_WORKTREE,
@@ -161,6 +169,5 @@ class TestVerifyPreflightRootGuardIntegration(unittest.TestCase):
         }
         srv.verify_preflight_purity("prgs", worktree_path=BRANCHES_WORKTREE)
 
-
 if __name__ == "__main__":
     unittest.main()

tests/test_sentry_observability.py

@@ -0,0 +1,412 @@
+"""Tests for optional self-hosted Sentry observability (#606).
+
+Covers the pure module (config, redaction, event/check-in builders) and the
+runtime capture paths using a fake ``sentry_sdk``, so nothing ever touches the
+network. Critically proves the feature is a no-op when disabled or DSN-less
+(acceptance criterion 1) and that secrets/paths/session-state are never sent
+(criterion 5).
+"""
+
+import sys
+import contextlib
+from pathlib import Path
+
+import pytest
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+import sentry_observability as so  # noqa: E402
+
+
+# ── Fake SDK ────────────────────────────────────────────────────────────────
+class _FakeScope:
+    def __init__(self):
+        self.tags = {}
+        self.extras = {}
+
+    def set_tag(self, k, v):
+        self.tags[k] = v
+
+    def set_extra(self, k, v):
+        self.extras[k] = v
+
+
+class FakeSentrySDK:
+    """Minimal stand-in exposing the SDK surface sentry_observability uses."""
+
+    def __init__(self):
+        self.init_kwargs = None
+        self.events = []
+        self.exceptions = []
+        self.checkins = []
+        self.last_scope = None
+
+    def init(self, **kwargs):
+        self.init_kwargs = kwargs
+
+    def capture_event(self, event):
+        self.events.append(event)
+
+    def capture_exception(self, exc):
+        self.exceptions.append(exc)
+
+    def capture_checkin(self, **payload):
+        self.checkins.append(payload)
+
+    @contextlib.contextmanager
+    def push_scope(self):
+        self.last_scope = _FakeScope()
+        yield self.last_scope
+
+
+@pytest.fixture(autouse=True)
+def _reset_state():
+    """Isolate module init state between tests."""
+    so.reset_for_tests()
+    yield
+    so.reset_for_tests()
+
+
+@pytest.fixture
+def fake_sdk(monkeypatch):
+    sdk = FakeSentrySDK()
+    monkeypatch.setattr(so, "sentry_sdk", sdk)
+    return sdk
+
+
+# ── Config / gating ─────────────────────────────────────────────────────────
+def test_disabled_by_default_empty_env():
+    cfg = so.load_config(env={})
+    assert cfg.enabled is False
+    assert cfg.active is False
+
+
+def test_enabled_flag_without_dsn_is_not_active():
+    cfg = so.load_config(env={"MCP_SENTRY_ENABLED": "1"})
+    assert cfg.enabled is True
+    assert cfg.dsn is None
+    assert cfg.active is False  # DSN required
+
+
+def test_dsn_without_enabled_flag_is_not_active():
+    cfg = so.load_config(env={"SENTRY_DSN": "https://[email protected]/1"})
+    assert cfg.active is False
+
+
+def test_active_requires_enabled_and_dsn():
+    cfg = so.load_config(
+        env={"MCP_SENTRY_ENABLED": "true", "SENTRY_DSN": "https://[email protected]/1"}
+    )
+    assert cfg.active is True
+
+
+def test_truthy_variants():
+    for val in ("1", "true", "YES", "On"):
+        cfg = so.load_config(env={"MCP_SENTRY_ENABLED": val})
+        assert cfg.enabled is True
+    for val in ("0", "false", "no", "", "off"):
+        cfg = so.load_config(env={"MCP_SENTRY_ENABLED": val})
+        assert cfg.enabled is False
+
+
+def test_traces_sample_rate_parsed_and_clamped():
+    assert so.load_config(env={"MCP_SENTRY_TRACES_SAMPLE_RATE": "0.25"}).traces_sample_rate == 0.25
+    assert so.load_config(env={"MCP_SENTRY_TRACES_SAMPLE_RATE": "5"}).traces_sample_rate == 1.0
+    assert so.load_config(env={"MCP_SENTRY_TRACES_SAMPLE_RATE": "-1"}).traces_sample_rate == 0.0
+    assert so.load_config(env={"MCP_SENTRY_TRACES_SAMPLE_RATE": "junk"}).traces_sample_rate == 0.0
+
+
+def test_safe_summary_has_no_dsn_value():
+    cfg = so.load_config(
+        env={"MCP_SENTRY_ENABLED": "1", "SENTRY_DSN": "https://[email protected]/1"}
+    )
+    summary = cfg.safe_summary()
+    assert summary["dsn_present"] is True
+    assert "secret" not in repr(summary)
+    assert "dsn" not in summary  # only presence, never the value
+
+
+# ── init_sentry ─────────────────────────────────────────────────────────────
+def test_init_noop_when_disabled(fake_sdk):
+    status = so.init_sentry(so.load_config(env={}))
+    assert status["initialized"] is False
+    assert fake_sdk.init_kwargs is None  # no SDK init
+    assert so.is_initialized() is False
+
+
+def test_init_noop_when_enabled_but_missing_dsn(fake_sdk):
+    status = so.init_sentry(so.load_config(env={"MCP_SENTRY_ENABLED": "1"}))
+    assert status["initialized"] is False
+    assert fake_sdk.init_kwargs is None
+
+
+def test_init_reports_missing_sdk(monkeypatch):
+    monkeypatch.setattr(so, "sentry_sdk", None)
+    status = so.init_sentry(
+        so.load_config(
+            env={"MCP_SENTRY_ENABLED": "1", "SENTRY_DSN": "https://[email protected]/1"}
+        )
+    )
+    assert status["initialized"] is False
+    assert "not installed" in status["reason"]
+
+
+def test_init_configures_sdk_with_scrubber(fake_sdk):
+    status = so.init_sentry(
+        so.load_config(
+            env={
+                "MCP_SENTRY_ENABLED": "1",
+                "SENTRY_DSN": "https://[email protected]/1",
+                "SENTRY_ENVIRONMENT": "prod",
+                "MCP_SENTRY_TRACES_SAMPLE_RATE": "0.1",
+            }
+        )
+    )
+    assert status["initialized"] is True
+    assert so.is_initialized() is True
+    kw = fake_sdk.init_kwargs
+    assert kw["dsn"] == "https://[email protected]/1"
+    assert kw["environment"] == "prod"
+    assert kw["traces_sample_rate"] == 0.1
+    assert kw["before_send"] is so.scrub_event
+    assert kw["send_default_pii"] is False
+
+
+def test_init_enable_logs_wires_log_scrubber(fake_sdk):
+    so.init_sentry(
+        so.load_config(
+            env={
+                "MCP_SENTRY_ENABLED": "1",
+                "SENTRY_DSN": "https://[email protected]/1",
+                "MCP_SENTRY_ENABLE_LOGS": "1",
+            }
+        )
+    )
+    exp = fake_sdk.init_kwargs["_experiments"]
+    assert exp["enable_logs"] is True
+    assert exp["before_send_log"] is so.scrub_event
+
+
+def test_init_never_raises_on_sdk_failure(monkeypatch):
+    class Boom:
+        def init(self, **kwargs):
+            raise RuntimeError("sentry down")
+
+    monkeypatch.setattr(so, "sentry_sdk", Boom())
+    status = so.init_sentry(
+        so.load_config(
+            env={"MCP_SENTRY_ENABLED": "1", "SENTRY_DSN": "https://[email protected]/1"}
+        )
+    )
+    assert status["initialized"] is False
+    assert "init failed" in status["reason"]
+
+
+# ── Redaction (fail closed) ─────────────────────────────────────────────────
+def test_build_tags_allowlist_only():
+    tags = so.build_tags(role="author", secret_thing="leak", pid=123)
+    assert tags["role"] == "author"
+    assert tags["pid"] == "123"
+    assert "secret_thing" not in tags
+
+
+def test_build_tags_hashes_session_id():
+    tags = so.build_tags(session_id="prgs-author-20479-cf9ac178")
+    assert "session_id" not in tags
+    assert "session_id_hash" in tags
+    assert tags["session_id_hash"] != "prgs-author-20479-cf9ac178"
+    assert len(tags["session_id_hash"]) == 12
+
+
+def test_build_tags_collapses_worktree_path():
+    tags = so.build_tags(
+        worktree_path="/Users/x/Development/Gitea-Tools/branches/issue-606-sentry-observability"
+    )
+    assert "worktree_path" not in tags
+    assert tags["worktree_category"] == "author"
+
+
+def test_build_tags_drops_value_that_scrubs_to_redacted():
+    # A tag value that is itself a token gets scrubbed then dropped.
+    tags = so.build_tags(capability="token abcdef1234567890")
+    assert "capability" not in tags
+
+
+def test_sanitize_path_categories():
+    assert so.sanitize_path("/repo/branches/review-pr-654") == "reviewer"
+    assert so.sanitize_path("/repo/branches/merge-pr-1") == "merger"
+    assert so.sanitize_path("/repo/branches/reconcile-pr-1") == "reconciler"
+    assert so.sanitize_path("/repo/branches/feat-issue-606") == "author"
+    assert so.sanitize_path("/x/y/Gitea-Tools") == "root"
+
+
+def test_redact_value_scrubs_secrets_and_paths():
+    out = so.redact_value(
+        {
+            "token": "abc123",
+            "note": "Authorization: Bearer sk_live_abcdefgh12345",
+            "path": "/Users/jasonwalker/Development/Gitea-Tools/secret",
+            "dsn": "https://[email protected]/1",
+            "safe": "hello",
+        }
+    )
+    assert out["token"] == so.REDACTED
+    assert out["dsn"] == so.REDACTED
+    assert "sk_live" not in out["note"]
+    assert so.REDACTED_PATH in out["path"]
+    assert "/Users/" not in out["path"]
+    assert out["safe"] == "hello"
+
+
+def test_redact_value_forbidden_prompt_and_session_state():
+    out = so.redact_value(
+        {"prompt": "full body", "session_state": "{...}", "keep": "ok"}
+    )
+    assert out["prompt"] == so.REDACTED
+    assert out["session_state"] == so.REDACTED
+    assert out["keep"] == "ok"
+
+
+def test_scrub_event_redacts_nested_and_drops_server_name():
+    event = {
+        "server_name": "some-host",
+        "message": "boom",
+        "extra": {"token": "leak", "ok": "1"},
+    }
+    scrubbed = so.scrub_event(event)
+    assert "server_name" not in scrubbed
+    assert scrubbed["extra"]["token"] == so.REDACTED
+    assert scrubbed["extra"]["ok"] == "1"
+
+
+def test_scrub_event_drops_non_dict():
+    assert so.scrub_event("not a dict") is None
+    assert so.scrub_event(None) is None
+
+
+# ── Event builders ──────────────────────────────────────────────────────────
+def test_build_blocker_event_structure_and_next_action():
+    event = so.build_blocker_event(
+        "active_foreign_lease",
+        message="blocked by foreign lease",
+        next_action="wait or adopt via allocator",
+        level="warning",
+        tags={"pr_number": 606, "session_id": "s-123"},
+    )
+    assert event["tags"]["blocker_type"] == "active_foreign_lease"
+    assert event["tags"]["pr_number"] == "606"
+    assert "session_id" not in event["tags"]
+    assert event["tags"]["session_id_hash"]
+    assert event["extra"]["canonical_next_action"] == "wait or adopt via allocator"
+    assert event["fingerprint"] == ["workflow-blocker", "active_foreign_lease"]
+
+
+def test_build_blocker_event_invalid_level_defaults_warning():
+    event = so.build_blocker_event("x", level="nonsense")
+    assert event["level"] == "warning"
+
+
+def test_build_checkin_payload_maps_slugs():
+    for key, slug in so.MONITOR_SLUGS.items():
+        payload = so.build_checkin_payload(key, "ok")
+        assert payload["monitor_slug"] == slug
+        assert payload["status"] == "ok"
+
+
+def test_build_checkin_payload_explicit_slug_passthrough():
+    payload = so.build_checkin_payload("custom-slug", "in_progress", duration=1.5)
+    assert payload["monitor_slug"] == "custom-slug"
+    assert payload["duration"] == 1.5
+
+
+def test_build_checkin_payload_rejects_bad_status():
+    with pytest.raises(ValueError):
+        so.build_checkin_payload("allocator_health", "bogus")
+
+
+def test_all_six_monitors_registered():
+    assert set(so.MONITOR_SLUGS) == {
+        "stale_lease_scan",
+        "terminal_lock_scan",
+        "allocator_health",
+        "namespace_health",
+        "dashboard_freshness",
+        "reconciler_cleanup",
+    }
+
+
+# ── Capture paths (fail open) ───────────────────────────────────────────────
+def test_capture_workflow_blocker_noop_when_disabled(fake_sdk):
+    # not initialised
+    event = so.capture_workflow_blocker("some_blocker", message="x")
+    assert isinstance(event, dict)  # still returns redacted event
+    assert fake_sdk.events == []  # but nothing sent
+
+
+def test_capture_workflow_blocker_sends_when_initialised(fake_sdk):
+    so.init_sentry(
+        so.load_config(
+            env={"MCP_SENTRY_ENABLED": "1", "SENTRY_DSN": "https://[email protected]/1"}
+        )
+    )
+    so.capture_workflow_blocker("terminal_lock_occupied", message="held")
+    assert len(fake_sdk.events) == 1
+    assert fake_sdk.events[0]["tags"]["blocker_type"] == "terminal_lock_occupied"
+
+
+def test_capture_exception_noop_when_disabled(fake_sdk):
+    assert so.capture_exception(ValueError("x")) is False
+    assert fake_sdk.exceptions == []
+
+
+def test_capture_exception_sends_scrubbed_tags(fake_sdk):
+    so.init_sentry(
+        so.load_config(
+            env={"MCP_SENTRY_ENABLED": "1", "SENTRY_DSN": "https://[email protected]/1"}
+        )
+    )
+    ok = so.capture_exception(
+        RuntimeError("bad"), tags={"mutation_tool": "gitea_merge_pr", "leaky": "x"}
+    )
+    assert ok is True
+    assert len(fake_sdk.exceptions) == 1
+    assert fake_sdk.last_scope.tags["mutation_tool"] == "gitea_merge_pr"
+    assert "leaky" not in fake_sdk.last_scope.tags
+
+
+def test_capture_exception_never_raises(monkeypatch, fake_sdk):
+    so.init_sentry(
+        so.load_config(
+            env={"MCP_SENTRY_ENABLED": "1", "SENTRY_DSN": "https://[email protected]/1"}
+        )
+    )
+
+    def boom(exc):
+        raise RuntimeError("sdk exploded")
+
+    monkeypatch.setattr(fake_sdk, "capture_exception", boom)
+    # Must swallow the SDK failure (fail open).
+    assert so.capture_exception(ValueError("y")) is False
+
+
+def test_monitor_checkin_noop_when_disabled(fake_sdk):
+    payload = so.monitor_checkin("allocator_health", "ok")
+    assert payload["monitor_slug"] == "gitea-mcp-allocator-health"
+    assert fake_sdk.checkins == []  # not sent while disabled
+
+
+def test_monitor_checkin_sends_when_initialised(fake_sdk):
+    so.init_sentry(
+        so.load_config(
+            env={"MCP_SENTRY_ENABLED": "1", "SENTRY_DSN": "https://[email protected]/1"}
+        )
+    )
+    so.monitor_checkin("stale_lease_scan", "ok")
+    assert fake_sdk.checkins == [
+        {"monitor_slug": "gitea-mcp-stale-lease-scan", "status": "ok"}
+    ]
+
+
+def test_monitor_checkin_invalid_status_returns_none(fake_sdk):
+    assert so.monitor_checkin("allocator_health", "bogus") is None
+    assert fake_sdk.checkins == []

tests/test_stable_branch_contamination_server.py

@@ -0,0 +1,188 @@
+"""Server wiring for stable-branch push contamination (#671).
+
+Exercises the MCP tools and the pre-flight enforcement gate against the durable
+contamination marker (isolated per-test state dir from conftest).
+"""
+
+from __future__ import annotations
+
+import os
+from unittest.mock import patch
+
+import gitea_mcp_server as srv
+
+
+def _clear_marker(remote="prgs"):
+    srv._clear_stable_contamination_marker(remote=remote)
+
+
+def teardown_function():
+    _clear_marker()
+
+
+# ── record tool marks a real direct push ─────────────────────────────────────
+
+def test_record_tool_marks_direct_master_push():
+    _clear_marker()
+    res = srv.gitea_record_stable_branch_push_attempt(
+        command="git push prgs master", remote="prgs"
+    )
+    assert res["contaminated"] is True
+    assert res["marked"] is True
+    assert res["marker"] is not None
+    assert res["marker"]["reason_class"] == "stable_branch_push"
+    # loaded back through the durable store
+    loaded = srv._load_stable_contamination_marker("prgs")
+    assert loaded is not None
+    assert loaded["ref"] == "master"
+
+
+def test_record_tool_dry_run_still_marks():
+    _clear_marker()
+    res = srv.gitea_record_stable_branch_push_attempt(
+        command="git push --dry-run prgs master", remote="prgs"
+    )
+    assert res["contaminated"] is True
+    assert res["marked"] is True
+
+
+def test_record_tool_feature_branch_does_not_mark():
+    _clear_marker()
+    res = srv.gitea_record_stable_branch_push_attempt(
+        command="git push prgs fix/issue-671-block-stable-branch-push",
+        remote="prgs",
+    )
+    assert res["contaminated"] is False
+    assert res["marked"] is False
+    assert srv._load_stable_contamination_marker("prgs") is None
+
+
+def test_record_tool_fetch_only_does_not_mark():
+    _clear_marker()
+    res = srv.gitea_record_stable_branch_push_attempt(
+        command="git fetch prgs", remote="prgs"
+    )
+    assert res["contaminated"] is False
+    assert res["marked"] is False
+
+
+def test_record_tool_mark_false_is_readonly():
+    _clear_marker()
+    res = srv.gitea_record_stable_branch_push_attempt(
+        command="git push prgs master", remote="prgs", mark=False
+    )
+    assert res["contaminated"] is True
+    assert res["marked"] is False
+    assert srv._load_stable_contamination_marker("prgs") is None
+
+
+def test_record_tool_redacts_secret_in_marker():
+    _clear_marker()
+    res = srv.gitea_record_stable_branch_push_attempt(
+        command="git push https://u:supersecret@host/o/r.git master",
+        remote="prgs",
+    )
+    assert res["marked"] is True
+    assert "supersecret" not in res["marker"]["command_summary"]
+
+
+def test_record_tool_root_checkout_local_commit_marks():
+    _clear_marker()
+    res = srv.gitea_record_stable_branch_push_attempt(
+        command=None,
+        remote="prgs",
+        current_branch="master",
+        head_sha="a" * 40,
+        remote_master_sha="b" * 40,
+        is_under_branches=False,
+    )
+    assert res["contaminated"] is True
+    assert res["marked"] is True
+    assert res["marker"]["reason_class"] == "root_checkout_commit"
+
+
+# ── audit tool: inspect + reconciler-only clear ──────────────────────────────
+
+def test_audit_inspect_reports_marker():
+    _clear_marker()
+    srv.gitea_record_stable_branch_push_attempt(
+        command="git push prgs master", remote="prgs"
+    )
+    out = srv.gitea_audit_stable_branch_contamination(action="inspect", remote="prgs")
+    assert out["contaminated"] is True
+    assert out["read_only"] is True
+
+
+def test_audit_clear_refused_for_non_reconciler():
+    _clear_marker()
+    srv.gitea_record_stable_branch_push_attempt(
+        command="git push prgs master", remote="prgs"
+    )
+    with patch.object(srv, "_actual_profile_role", return_value="author"):
+        out = srv.gitea_audit_stable_branch_contamination(action="clear", remote="prgs")
+    assert out["success"] is False
+    assert out["reasons"]
+    # marker survives a refused clear
+    assert srv._load_stable_contamination_marker("prgs") is not None
+
+
+def test_audit_clear_allowed_for_reconciler():
+    _clear_marker()
+    srv.gitea_record_stable_branch_push_attempt(
+        command="git push prgs master", remote="prgs"
+    )
+    identity = srv._stable_contamination_profile_identity()
+    with patch.object(srv, "_actual_profile_role", return_value="reconciler"):
+        out = srv.gitea_audit_stable_branch_contamination(
+            action="clear", remote="prgs", profile_identity=identity
+        )
+    assert out["success"] is True
+    assert srv._load_stable_contamination_marker("prgs") is None
+
+
+# ── pre-flight enforcement gate ──────────────────────────────────────────────
+
+def _force_gate_env():
+    return patch.dict(os.environ, {"GITEA_TEST_FORCE_STABLE_CONTAMINATION": "1"})
+
+
+def test_gate_blocks_gated_mutation_when_contaminated():
+    _clear_marker()
+    srv.gitea_record_stable_branch_push_attempt(
+        command="git push prgs master", remote="prgs"
+    )
+    with _force_gate_env(), patch.object(srv, "_actual_profile_role", return_value="author"):
+        for task in ("merge_pr", "review_pr", "close_issue", "create_pr"):
+            try:
+                srv._enforce_stable_branch_contamination_gate(task, "prgs")
+                raised = False
+            except RuntimeError as exc:
+                raised = True
+                assert "#671" in str(exc)
+            assert raised, task
+
+
+def test_gate_allows_comment_for_handoff_when_contaminated():
+    _clear_marker()
+    srv.gitea_record_stable_branch_push_attempt(
+        command="git push prgs master", remote="prgs"
+    )
+    with _force_gate_env(), patch.object(srv, "_actual_profile_role", return_value="author"):
+        # must not raise — worker can still post the durable audit comment
+        srv._enforce_stable_branch_contamination_gate("comment_issue", "prgs")
+        srv._enforce_stable_branch_contamination_gate("lock_issue", "prgs")
+
+
+def test_gate_exempts_reconciler_when_contaminated():
+    _clear_marker()
+    srv.gitea_record_stable_branch_push_attempt(
+        command="git push prgs master", remote="prgs"
+    )
+    with _force_gate_env(), patch.object(srv, "_actual_profile_role", return_value="reconciler"):
+        srv._enforce_stable_branch_contamination_gate("merge_pr", "prgs")
+
+
+def test_gate_noop_when_not_contaminated():
+    _clear_marker()
+    with _force_gate_env(), patch.object(srv, "_actual_profile_role", return_value="author"):
+        srv._enforce_stable_branch_contamination_gate("merge_pr", "prgs")

tests/test_stable_branch_push_guard.py

@@ -0,0 +1,341 @@
+"""Tests for the direct stable-branch push guard (#671).
+
+Covers the acceptance criteria:
+1. detect shell ``git push <remote> master`` equivalents
+2. detect root/control-checkout local commits not on an issue branch
+3. contamination record shape
+4. fail-closed gate on review/merge/close/completion (reconciler-exempt)
+5. AC5 case matrix: no-op dry-run push, real direct push, sanctioned Gitea
+   merge, fetch-only, root-checkout local commit; plus feature-branch push
+   still allowed and sanctioned merge still allowed
+6. redaction of credentials in logged command summaries
+"""
+
+import stable_branch_push_guard as guard
+
+
+# ── AC1: detect direct stable-branch push equivalents ────────────────────────
+
+def test_plain_git_push_remote_master_is_contamination():
+    res = guard.classify_push_command("git push prgs master")
+    assert res["is_git_push"] is True
+    assert res["targets_stable"] is True
+    assert res["stable_refs"] == ["master"]
+    assert res["contamination"] is True
+    assert res["reasons"]
+
+
+def test_push_main_and_dev_detected():
+    for ref in ("main", "dev", "develop", "development"):
+        res = guard.classify_push_command(f"git push origin {ref}")
+        assert res["contamination"] is True, ref
+        assert res["stable_refs"] == [ref]
+
+
+def test_head_colon_master_refspec_detected():
+    res = guard.classify_push_command("git push prgs HEAD:master")
+    assert res["targets_stable"] is True
+    assert res["stable_refs"] == ["master"]
+    assert res["contamination"] is True
+
+
+def test_full_refspec_force_plus_detected():
+    res = guard.classify_push_command(
+        "git push prgs +refs/heads/tmp:refs/heads/master"
+    )
+    assert res["contamination"] is True
+    assert res["is_force"] is True
+    assert res["stable_refs"] == ["master"]
+
+
+def test_force_flag_to_master_detected():
+    res = guard.classify_push_command("git push --force prgs master")
+    assert res["contamination"] is True
+    assert res["is_force"] is True
+
+
+def test_delete_refspec_master_detected():
+    res = guard.classify_push_command("git push prgs :master")
+    assert res["contamination"] is True
+    assert res["is_delete"] is True
+
+
+def test_delete_flag_master_detected():
+    res = guard.classify_push_command("git push --delete prgs master")
+    assert res["contamination"] is True
+    assert res["is_delete"] is True
+
+
+def test_push_detected_inside_compound_command():
+    res = guard.classify_push_command("cd repo && git push prgs master && echo ok")
+    assert res["contamination"] is True
+    assert res["stable_refs"] == ["master"]
+
+
+# ── AC5: no-op / dry-run push still proves intent ────────────────────────────
+
+def test_dry_run_push_to_master_proves_intent():
+    res = guard.classify_push_command("git push --dry-run prgs master")
+    assert res["is_dry_run"] is True
+    assert res["contamination"] is True
+    assert res["proves_intent"] is True
+    assert "intent" in " ".join(res["reasons"]).lower()
+
+
+def test_short_dry_run_flag_n_detected():
+    res = guard.classify_push_command("git push -n prgs master")
+    assert res["is_dry_run"] is True
+    assert res["contamination"] is True
+
+
+# ── AC5 negative: feature-branch push still allowed ──────────────────────────
+
+def test_feature_branch_push_not_flagged():
+    res = guard.classify_push_command(
+        "git push prgs fix/issue-671-block-stable-branch-push"
+    )
+    assert res["is_git_push"] is True
+    assert res["targets_stable"] is False
+    assert res["contamination"] is False
+    assert res["reasons"] == []
+
+
+def test_feature_branch_head_refspec_not_flagged():
+    res = guard.classify_push_command(
+        "git push prgs HEAD:fix/issue-671-block-stable-branch-push"
+    )
+    assert res["contamination"] is False
+    assert res["targets_stable"] is False
+
+
+def test_branch_named_like_master_substring_not_flagged():
+    # 'master-notes' is not the stable 'master'.
+    res = guard.classify_push_command("git push prgs master-notes")
+    assert res["contamination"] is False
+    assert res["targets_stable"] is False
+
+
+# ── AC5 negative: fetch-only operations ──────────────────────────────────────
+
+def test_git_fetch_not_a_push():
+    res = guard.classify_push_command("git fetch prgs")
+    assert res["is_git_push"] is False
+    assert res["is_fetch_or_pull"] is True
+    assert res["contamination"] is False
+
+
+def test_git_pull_ff_only_master_not_a_push():
+    res = guard.classify_push_command("git pull --ff-only prgs master")
+    assert res["is_git_push"] is False
+    assert res["is_fetch_or_pull"] is True
+    assert res["contamination"] is False
+
+
+# ── AC5 negative: sanctioned Gitea merge is not a push ───────────────────────
+
+def test_gitea_merge_pr_tool_is_not_a_push():
+    res = guard.classify_push_command("gitea_merge_pr(pr_number=671, remote='prgs')")
+    assert res["is_git_push"] is False
+    assert res["contamination"] is False
+
+
+def test_gitea_api_merge_is_not_a_push():
+    res = guard.classify_push_command(
+        "curl -X POST https://gitea.example/api/v1/repos/o/r/pulls/671/merge"
+    )
+    assert res["is_git_push"] is False
+    assert res["contamination"] is False
+
+
+# ── ambiguous bare push: reported, not auto-contaminating ────────────────────
+
+def test_bare_push_is_ambiguous_not_contaminating():
+    res = guard.classify_push_command("git push prgs")
+    assert res["is_git_push"] is True
+    assert res["ambiguous_target"] is True
+    assert res["contamination"] is False
+    assert res["reasons"]  # surfaced as a warning
+
+
+# ── AC2: root/control-checkout local commit detection ────────────────────────
+
+def test_root_checkout_commit_ahead_of_master_flagged():
+    res = guard.assess_root_checkout_local_commit(
+        current_branch="master",
+        head_sha="a" * 40,
+        remote_master_sha="b" * 40,
+        is_under_branches=False,
+    )
+    assert res["contamination"] is True
+    assert res["reasons"]
+
+
+def test_root_checkout_clean_at_master_not_flagged():
+    sha = "c" * 40
+    res = guard.assess_root_checkout_local_commit(
+        current_branch="master",
+        head_sha=sha,
+        remote_master_sha=sha,
+        is_under_branches=False,
+    )
+    assert res["contamination"] is False
+    assert res["unknown"] is False
+
+
+def test_branches_worktree_commit_is_exempt():
+    res = guard.assess_root_checkout_local_commit(
+        current_branch="fix/issue-671-block-stable-branch-push",
+        head_sha="a" * 40,
+        remote_master_sha="b" * 40,
+        is_under_branches=True,
+    )
+    assert res["contamination"] is False
+
+
+def test_root_checkout_ahead_count_flagged():
+    res = guard.assess_root_checkout_local_commit(
+        current_branch="master",
+        head_sha="",
+        remote_master_sha="",
+        is_under_branches=False,
+        ahead_count=2,
+    )
+    assert res["contamination"] is True
+
+
+def test_root_checkout_unknown_when_state_missing():
+    res = guard.assess_root_checkout_local_commit(
+        current_branch="master",
+        head_sha="",
+        remote_master_sha="",
+        is_under_branches=False,
+    )
+    assert res["contamination"] is False
+    assert res["unknown"] is True
+
+
+def test_root_checkout_non_stable_branch_out_of_scope():
+    res = guard.assess_root_checkout_local_commit(
+        current_branch="feature/x",
+        head_sha="a" * 40,
+        remote_master_sha="b" * 40,
+        is_under_branches=False,
+    )
+    assert res["contamination"] is False
+
+
+# ── AC3: contamination record shape ──────────────────────────────────────────
+
+def test_build_contamination_record_shape_and_redaction():
+    rec = guard.build_contamination_record(
+        reason_class="stable_branch_push",
+        command_redacted="git push https://user:[email protected]/o/r.git master",
+        session_id="prgs-author-123",
+        remote="prgs",
+        ref="master",
+        role="author",
+    )
+    assert rec["kind"] == guard.CONTAMINATION_KIND
+    assert rec["reason_class"] == "stable_branch_push"
+    assert rec["remote"] == "prgs"
+    assert rec["ref"] == "master"
+    assert rec["cleared_by_reconciler"] is False
+    # secret must never survive into the durable record
+    assert "tok@" not in rec["command_summary"]
+    assert "***@" in rec["command_summary"]
+
+
+# ── AC4: fail-closed gate on gated mutations ─────────────────────────────────
+
+def _marker():
+    return guard.build_contamination_record(
+        reason_class="stable_branch_push",
+        command_redacted="git push prgs master",
+        remote="prgs",
+        ref="master",
+        role="author",
+    )
+
+
+def test_gate_blocks_gated_mutations_for_author():
+    marker = _marker()
+    for task in ("create_pr", "merge_pr", "close_issue", "review_pr",
+                 "submit_pr_review", "commit_files", "close_pr"):
+        gate = guard.assess_contamination_gate(marker, task=task, actual_role="author")
+        assert gate["block"] is True, task
+        assert gate["reasons"]
+
+
+def test_gate_allows_comment_and_lock_for_handoff():
+    marker = _marker()
+    for task in ("comment_issue", "lock_issue", "create_issue", "mark_issue"):
+        gate = guard.assess_contamination_gate(marker, task=task, actual_role="author")
+        assert gate["block"] is False, task
+
+
+def test_gate_exempts_reconciler_audit_path():
+    marker = _marker()
+    gate = guard.assess_contamination_gate(marker, task="close_pr", actual_role="reconciler")
+    assert gate["block"] is False
+
+
+def test_gate_no_marker_allows_everything():
+    gate = guard.assess_contamination_gate(None, task="merge_pr", actual_role="merger")
+    assert gate["block"] is False
+
+
+def test_gate_cleared_marker_allows_everything():
+    marker = _marker()
+    marker["cleared_by_reconciler"] = True
+    gate = guard.assess_contamination_gate(marker, task="merge_pr", actual_role="merger")
+    assert gate["block"] is False
+
+
+def test_same_worker_cannot_self_clear_by_role():
+    # A merger/reviewer/author role is still gated — only reconciler is exempt.
+    marker = _marker()
+    for role in ("author", "reviewer", "merger"):
+        gate = guard.assess_contamination_gate(marker, task="merge_pr", actual_role=role)
+        assert gate["block"] is True, role
+
+
+def test_format_gate_error_mentions_issue():
+    marker = _marker()
+    gate = guard.assess_contamination_gate(marker, task="merge_pr", actual_role="merger")
+    msg = guard.format_contamination_gate_error(gate)
+    assert "#671" in msg
+    assert "contaminat" in msg.lower()
+
+
+# ── redaction unit coverage ──────────────────────────────────────────────────
+
+def test_redact_url_userinfo():
+    out = guard.redact_command("git push https://bob:secretpat@host/o/r.git master")
+    assert "secretpat" not in out
+    assert "***@" in out
+    assert "master" in out  # structure preserved for audit
+
+
+def test_redact_token_assignment():
+    out = guard.redact_command("GITEA_TOKEN=abcdef123456 git push prgs master")
+    assert "abcdef123456" not in out
+    assert "GITEA_TOKEN=***" in out
+
+
+def test_redact_empty():
+    assert guard.redact_command(None) == ""
+    assert guard.redact_command("") == ""
+
+
+# ── detect_stable_push over iterables ────────────────────────────────────────
+
+def test_detect_stable_push_iterable_finds_first_contamination():
+    cmds = ["git status", "git push prgs master", "echo done"]
+    res = guard.detect_stable_push(cmds)
+    assert res["contamination"] is True
+
+
+def test_detect_stable_push_iterable_all_safe():
+    cmds = ["git status", "git push prgs feature/x", "git fetch prgs"]
+    res = guard.detect_stable_push(cmds)
+    assert res["contamination"] is False

tests/test_workspace_guard_alignment.py

@@ -100,7 +100,23 @@ class TestRuntimeContextGuardAlignment(unittest.TestCase):
         srv._preflight_in_test_mode = self._orig_in_test
         self._env_patch.stop()
 
-    def test_runtime_context_and_guard_share_resolved_workspace(self):
+    @mock.patch("subprocess.run")
+    @mock.patch("os.path.isdir", return_value=True)
+    @mock.patch("os.path.exists", return_value=True)
+    def test_runtime_context_and_guard_share_resolved_workspace(
+        self, _exists, _isdir, mock_run
+    ):
+        def run_side_effect(cmd, *args, **kwargs):
+            res = MagicMock(returncode=0)
+            if "--git-common-dir" in cmd:
+                res.stdout = f"{CONTROL_ROOT}/.git\n"
+            elif "--show-toplevel" in cmd:
+                cwd = cmd[cmd.index("-C") + 1] if "-C" in cmd else ""
+                res.stdout = f"{cwd}\n"
+            else:
+                res.stdout = f"{CONTROL_ROOT}\n"
+            return res
+        mock_run.side_effect = run_side_effect
         with mock.patch.object(srv, "PROJECT_ROOT", MCP_PROCESS_ROOT):
             ctx = srv._resolve_author_mutation_context(BRANCHES_WORKTREE)
             status = srv.assess_preflight_status(worktree_path=BRANCHES_WORKTREE)

webui/worktree_scanner.py

@@ -14,11 +14,7 @@ from merged_cleanup_reconcile import (
     read_issue_lock,
     read_local_worktree_state,
 )
-
-_REVIEW_WORKTREE_RE = re.compile(
-    r"branches/(?:review-pr\d+|merge-simulation-pr\d+|review-[\w-]+)",
-    re.IGNORECASE,
-)
+from reviewer_worktree import REVIEW_WORKTREE_RE
 
 CLASSIFICATIONS = frozenset({
     "active-pr",
@@ -147,7 +143,7 @@ def classify_entry(
     if not record:
         return "orphan", "Directory exists but is not a registered git worktree"
 
-    if record.get("detached") and _REVIEW_WORKTREE_RE.search(rel_path):
+    if record.get("detached") and REVIEW_WORKTREE_RE.search(rel_path):
         return "detached-review", "Detached HEAD in reviewer/simulation worktree"
 
     if state.get("exists") and state.get("clean"):

worktree_cleanup_audit.py

@@ -35,7 +35,7 @@ from datetime import datetime, timezone
 from typing import Any
 
 from merged_cleanup_reconcile import branch_worktree_folder, read_local_worktree_state
-from reviewer_worktree import parse_dirty_tracked_files
+from reviewer_worktree import parse_dirty_tracked_files, REVIEW_WORKTREE_RE
 
 PROTECTED_BRANCHES = frozenset({"master", "main", "dev"})
 DEFAULT_TTL_HOURS = float(os.environ.get("GITEA_WORKTREE_TTL_HOURS", "24") or 24)
@@ -508,10 +508,8 @@ DISPOSITIONS = frozenset({
     "unsafe_unknown",
 })
 
-REVIEW_WORKTREE_RE = re.compile(
-    r"branches/(?:review-pr\d+|merge-simulation-pr\d+|review-[\w-]+)",
-    re.IGNORECASE,
-)
+
+
 
 
 def normalize_path(path: str) -> str: