fix(mcp): consume canonical target root in cross-repository operations (Closes #741)

#706 introduced the immutable `canonical_repository_root` and #739/#740 routed
three consumption paths through it. The paths #740 left behind all shared one
shape: the *filesystem* guards had been migrated to the canonical root, but
*repository identity* still bottomed out in `_local_git_remote_url`, which ran
`git remote get-url` with `cwd=PROJECT_ROOT` — always the Gitea-Tools install
checkout. The two halves of a single assessment therefore described two
different repositories.

For a namespace bound to another repository this inverts the guards rather than
merely weakening them: an operation naming the genuinely bound target is
rejected, while one naming Gitea-Tools is accepted.

Central helper
--------------
Adds `_canonical_local_git_root()` as the single place a target-repository root
is resolved: the configured canonical root when one is declared, else
`PROJECT_ROOT`. A configured-but-invalid root is never silently replaced by the
install checkout. Single-repository behaviour is byte-for-byte unchanged.

Defects fixed
-------------
* `_local_git_remote_url` now runs in the canonical target root, which corrects
  every downstream identity consumer at once (`_resolve`, the #530 remote/repo
  guard, the anti-stomp org/repo fill, `_workspace_repository_slug`).
* `_verify_role_mutation_workspace` omitted `configured_canonical_root`, so the
  #274 branches-only / worktree-membership guards validated
  `Gitea-Tools/branches/` instead of the bound target. It now threads the root
  exactly as `_resolve_namespace_mutation_context` does.
* `_resolve` derived omitted coordinates by looking a remote up *by name*. A
  target checkout commonly names its remote `origin` rather than `prgs`, so the
  lookup returned None and the coordinates fell through to the remote-wide
  default target — an unrelated repository. It now prefers
  `_canonical_repository_slug`, which probes candidate remote names.
* Explicit `org`/`repo` short-circuit the #530 match check, so caller
  coordinates bypassed validation entirely. They may now only *confirm* a
  canonical binding, never override it, and fail closed in both directions.
* Reconciler ancestry, fetch, worktree-inventory and cleanup call sites, the
  author worktree derivation in `gitea_lock_issue`/`gitea_create_pr`, and the
  `control_clean` porcelain probe now use the canonical target root.
* `gitea_config`: v2-`environments` silently *dropped* `canonical_repository_root`
  during flattening, so such a namespace fell back to the install root — a
  fail-open. It is now validated and propagated. The v1 path validates it too,
  so all three loaders behave identically.

Preserved as installation-scoped
--------------------------------
Server parity (`master_parity_gate`), workflow/schema/skill loading, self-code
hashing and stale-runtime detection, and `mirror_refs.sh` lookup remain anchored
to `PROJECT_ROOT`. The `server_implementation` vs `target_repository` parity
dimensions from #740 stay separately labelled, and only the server dimension
gates mutations.

Tests
-----
`tests/test_issue_741_canonical_root_consumers.py` (51 tests, 52 subtests) drives
a role-by-operation matrix over author/reviewer/merger/reconciler against:
correct cross-repository target, wrong repository, wrong worktree, explicit
matching and mismatched coordinates, missing/invalid canonical root, immutable
first-bind, and request-override attempts — plus both cross-repository
directions and all three config loaders. Real git repositories, no network, no
branch deletion, no merge.

The module reinstalls the genuine `_local_git_remote_url` per test: an autouse
conftest fixture permanently reassigns it to a working-directory-independent
stub, which is precisely the behaviour under test.

Full suite: 3408 passed, 6 skipped, 2 failed. Both failures
(`test_issue_702_review_findings_f1_f6`, `test_reconciler_supersession_close`)
reproduce identically on clean master c908ed6050 and are pre-existing.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01AYGdWAwuA6UNDc9c3CGipU

docs/canonical-repository-root.md

@@ -0,0 +1,153 @@
+# Installation root vs canonical target repository root
+
+## Purpose
+
+This document (tracked as issue #741, building on #706 and #739/#740) explains
+the two distinct filesystem roots the Gitea-Tools MCP server reasons about, why
+conflating them silently targets the wrong repository, and which rule applies
+when you add a new consumer.
+
+It is the repository-scope companion to
+[`gitea-execution-profiles.md`](gitea-execution-profiles.md) (the profile model)
+and [`gitea-dual-namespace-deployment.md`](gitea-dual-namespace-deployment.md)
+(the per-role namespace model).
+
+## The two roots
+
+| | Installation root | Canonical target repository root |
+|---|---|---|
+| What it is | The checkout the server *code* lives in | The working root of the repository whose issues/PRs/branches the namespace *mutates* |
+| How it is derived | `PROJECT_ROOT = os.path.dirname(os.path.abspath(__file__))` | Configured per namespace, then pinned immutably into the session |
+| Configured by | Nothing — it follows the script | `canonical_repository_root` profile field, or the `GITEA_CANONICAL_REPOSITORY_ROOT` environment variable |
+| Changes at runtime? | No | No — first bind wins for the life of the process |
+| Accessor | `PROJECT_ROOT` | `_canonical_local_git_root()` (filesystem) / `_canonical_repository_slug()` (identity) |
+
+For a **single-repository** namespace — every Gitea-Tools namespace today — the
+two roots are the same path, and nothing about the existing behaviour changes.
+The distinction only becomes observable once a namespace is pointed at a
+different repository.
+
+## Which root does my code need?
+
+Ask what the operation is *about*, not where the file happens to sit.
+
+**Use the installation root (`PROJECT_ROOT`)** when the operation concerns the
+Gitea-Tools software itself:
+
+- server implementation / version parity (`master_parity_gate`, the
+  `startup_head` vs `current_head` staleness gate);
+- loading the server's own workflow, schema and skill files;
+- self-code hashing and stale-runtime detection;
+- locating installed scripts such as `mirror_refs.sh`.
+
+These are intentionally install-scoped. Do not "fix" them.
+
+**Use the canonical target root (`_canonical_local_git_root()`)** when the
+operation concerns the repository being worked on:
+
+- `git remote get-url` for repository identity;
+- branch creation, push, and commit;
+- ancestry and merge-base proofs;
+- worktree inventory, cleanup, and branch deletion;
+- any local git subprocess whose result feeds a mutation guard.
+
+**If you cannot tell, fail closed.** An ambiguous consumer that guesses the
+install root is the exact defect class #741 exists to eliminate.
+
+## Why conflating them inverts the guards
+
+Before #741, `_local_git_remote_url()` ran `git remote get-url` with
+`cwd=PROJECT_ROOT` unconditionally. Every consumer of repository *identity* —
+`_resolve`, the #530 remote/repo guard, the anti-stomp org/repo fill,
+`_workspace_repository_slug` — therefore read the Gitea-Tools remote and called
+it "the workspace", no matter which repository the namespace was bound to.
+
+For a namespace whose canonical root points elsewhere, this **inverts** the
+guard rather than merely weakening it:
+
+- an operation naming the genuinely bound target repository is **rejected**,
+  because that slug does not appear in the Gitea-Tools remote URL;
+- an operation naming Gitea-Tools is **accepted**.
+
+The filesystem guards (#274 branches-only and worktree membership) had already
+been migrated to the canonical root by #706, so the two halves of a single
+assessment described two different repositories.
+
+A related subtlety: repository identity must not be derived by looking a remote
+up by *name*. A target checkout commonly names its remote `origin` rather than
+`prgs`, so a name-keyed lookup returns nothing and the omitted coordinates fall
+through to the remote-wide default *target* — an unrelated repository.
+`_canonical_repository_slug()` probes candidate remote names against the
+canonical root instead.
+
+`_canonical_local_git_root()` is now the one place a target root is resolved.
+Do not re-derive it; new code that needs a target root calls that helper.
+
+## Configuration
+
+Declare the binding on the profile, alongside `allowed_repositories`:
+
+```json
+{
+  "profiles": {
+    "example-author": {
+      "role": "author",
+      "canonical_repository_root": "/absolute/path/to/target-repo",
+      "allowed_repositories": ["Example-Org/target-repo"]
+    }
+  }
+}
+```
+
+The namespace-scoped environment variable
+`GITEA_CANONICAL_REPOSITORY_ROOT` overrides the profile field, and is normally
+exported next to the server `cwd` in the MCP client configuration.
+
+Validation is layered, and each layer fails closed:
+
+1. **Config load.** The path must be a non-empty absolute string. All supported
+   loaders — v1, v2-`environments`, and v2-`contexts` — validate it identically.
+   (Before #741 only the v2-`contexts` loader validated it, and
+   v2-`environments` silently *dropped* the field during flattening, so the
+   namespace fell back to the install root — a fail-open.)
+2. **Bind time.** The path must exist, be a git repository, and resolve to a
+   repository identity matching the session's authorized slug. A configured but
+   unresolvable root is never replaced by the install identity.
+3. **Every mutation.** The pinned root is compared against the live configured
+   value; a mismatch is treated as a forged or conflicting binding.
+
+`allowed_repositories` remains a separate authorization boundary (#714): the
+canonical root determines *which* repository is derived, and
+`allowed_repositories` determines whether the session may act on it. A root that
+resolves to a repository outside that list fails closed.
+
+## Explicit coordinates confirm, never override
+
+Explicit `org`/`repo` arguments may **confirm** an existing canonical binding.
+They can never establish, complete, or replace one. A request naming a
+repository that contradicts the binding fails closed, in both directions:
+
+- a Gitea-Tools-rooted namespace cannot mutate another repository;
+- a namespace rooted at another repository cannot mutate Gitea-Tools.
+
+This matters because both-explicit coordinates short-circuit the #530
+remote/repo match check, so without this rule a caller could name any repository
+and skip validation entirely.
+
+No request-supplied workspace, remote, owner, repository, or worktree can
+replace the immutable root.
+
+## Parity is reported per dimension
+
+`gitea_assess_master_parity` reports two separately labelled dimensions:
+
+- `server_implementation` — the Gitea-Tools installation checkout. Its
+  `startup_head` / `current_head` / `stale` / `restart_required` fields keep
+  their original meaning, and **only this dimension gates mutations**: the
+  running process executes the code it started with, so a merged fix is not live
+  until the daemon restarts.
+- `target_repository` — the configured canonical target checkout and its
+  last-known remote master.
+
+"In parity" is a statement about one dimension, never about the whole system.
+Read the dimension you actually care about.

gitea_config.py

@@ -272,6 +272,15 @@ def load_config(path=None):
         )
     if not isinstance(data.get("profiles"), dict):
         raise ConfigError(f"{path} must be a JSON object with a 'profiles' object")
+    # #741: the v1 path returns `data` unflattened, so nothing else validates
+    # the cross-repository binding before gitea_auth.get_profile() reads it.
+    # Validate it here so every supported loader treats the field identically
+    # (a relative or blank path must never reach the runtime guard).
+    for _name, _profile in data["profiles"].items():
+        if isinstance(_profile, dict):
+            _validate_canonical_repository_root(
+                _name, _profile.get("canonical_repository_root")
+            )
     return data
 
 
@@ -358,6 +367,14 @@ def _flatten_identity(env_name, svc_name, svc, ident_name, ident):
     for key in ("role", "username", "execution_profile", "audit_label"):
         if ident.get(key):
             profile[key] = ident[key]
+    # #741: the cross-repository binding must survive flattening. Previously
+    # this key was silently dropped here, so a v2-environments namespace that
+    # declared canonical_repository_root fell back to the *installation* root
+    # and mutated Gitea-Tools instead of its target repository — a fail-open.
+    # Validate it exactly as the v2-contexts loader does before propagating.
+    _validate_canonical_repository_root(addr, ident.get("canonical_repository_root"))
+    if ident.get("canonical_repository_root"):
+        profile["canonical_repository_root"] = ident["canonical_repository_root"]
     return addr, profile
 
 

gitea_mcp_server.py

@@ -393,6 +393,35 @@ def _configured_canonical_root() -> tuple[str | None, str | None]:
     return crr.configured_canonical_root(profile, os.environ)
 
 
+def _canonical_local_git_root() -> str:
+    """Local git working root for *target-repository* operations (#741).
+
+    Two distinct roots exist and must never be conflated:
+
+    * ``PROJECT_ROOT`` — the Gitea-Tools **installation** checkout, i.e. where
+      this server script lives. Server implementation/version parity, workflow
+      and skill file loading, and self-code staleness detection are anchored
+      here and must stay that way.
+    * the **canonical target repository root** — the working root of the
+      repository whose issues/PRs/branches the namespace actually mutates.
+
+    Every local git invocation that reads or proves *target repository* state
+    (remote identity, ancestry, worktree inventory, cleanup) must run here, or
+    a cross-repository namespace silently operates on Gitea-Tools instead.
+
+    Returns the resolved canonical target root when one is configured, else
+    ``PROJECT_ROOT`` — which preserves the single-repository default exactly.
+    A configured-but-invalid root is *not* silently replaced by the install
+    checkout: it is returned as-is so downstream git calls fail rather than
+    succeed against the wrong repository, and
+    :func:`_enforce_canonical_repository_root` fails the mutation closed first.
+    """
+    configured, _source = _configured_canonical_root()
+    if not configured:
+        return PROJECT_ROOT
+    return crr.resolve_repo_toplevel(configured) or os.path.realpath(configured)
+
+
 def _resolve_preflight_workspace_path(worktree_path: str | None = None) -> str:
     """Resolve the namespace-scoped workspace root inspected by pre-flight guards.
 
@@ -1448,6 +1477,12 @@ def _verify_role_mutation_workspace(
     git_state = issue_lock_worktree.read_worktree_git_state(
         _resolve_preflight_workspace_path(worktree_path)
     )
+    # #741: thread the configured canonical root exactly as
+    # _resolve_namespace_mutation_context does. Omitting it here made the two
+    # paths disagree: the #274 branches-only / worktree-membership guards fell
+    # back to the install checkout and validated Gitea-Tools/branches/ instead
+    # of the target repository the namespace is actually bound to.
+    _configured_root, _configured_source = _configured_canonical_root()
     assessment = nwb.assess_namespace_mutation_workspace(
         role_kind=role,
         worktree_path=worktree_path,
@@ -1458,6 +1493,7 @@ def _verify_role_mutation_workspace(
         ),
         profile_name=get_profile().get("profile_name"),
         current_branch=git_state.get("current_branch"),
+        configured_canonical_root=_configured_root,
     )
     if assessment["block"]:
         raise RuntimeError(
@@ -1648,6 +1684,45 @@ def _workspace_repository_slug(remote: str | None) -> str | None:
     return session_ctx.format_repository_slug(parsed[0], parsed[1])
 
 
+def _canonical_repository_slug(
+    profile: dict,
+    remote: str | None,
+) -> tuple[str | None, list[str]]:
+    """Repository identity of the *configured* canonical root, if any (#739 F2).
+
+    Returns ``(slug, reasons)``. A namespace with no configured
+    ``canonical_repository_root`` yields ``(None, [])`` so callers keep the
+    install-derived single-repository default. A configured root that cannot be
+    resolved to a repository identity yields ``(None, reasons)`` — a fail-closed
+    signal, never a silent fallback to the installation checkout, because that
+    fallback is exactly what lets a cross-repository namespace validate against
+    the wrong repository.
+
+    Env-over-profile precedence and the existence / git-toplevel / resolvable
+    remote-identity validation all live in ``crr``.
+    """
+    configured_value, configured_source = crr.configured_canonical_root(
+        profile, os.environ
+    )
+    if not configured_value:
+        return None, []
+    assessment = crr.assess_canonical_repository_root(
+        configured_value=configured_value,
+        source=configured_source,
+        expected_slug=None,
+        process_project_root=PROJECT_ROOT,
+        remote=remote,
+        require_binding=True,
+    )
+    slug = assessment.get("resolved_slug")
+    if assessment.get("block") or not slug:
+        return None, list(assessment.get("reasons") or [
+            "configured canonical repository root has no resolvable "
+            "repository identity (fail closed)"
+        ])
+    return slug, []
+
+
 def _trusted_session_repository(
     profile: dict,
     remote: str | None,
@@ -1686,32 +1761,10 @@ def _trusted_session_repository(
     # self-authorizing). Env-over-profile precedence and fail-closed validation
     # (existence, git toplevel, resolvable remote identity) are handled by
     # ``crr``; unconfigured single-repo namespaces keep the install-derived slug.
-    configured_value, configured_source = crr.configured_canonical_root(
-        profile, os.environ
-    )
-    if configured_value:
-        assessment = crr.assess_canonical_repository_root(
-            configured_value=configured_value,
-            source=configured_source,
-            expected_slug=None,
-            process_project_root=PROJECT_ROOT,
-            remote=remote,
-            require_binding=True,
-        )
-        slug = assessment.get("resolved_slug")
-        if assessment.get("block") or not slug:
-            return {
-                "org": None,
-                "repository": None,
-                "reasons": assessment.get("reasons")
-                or [
-                    "configured canonical repository root has no resolvable "
-                    "repository identity; session repository cannot be "
-                    "authorized (fail closed)"
-                ],
-            }
-    else:
-        slug = _workspace_repository_slug(remote)
+    canonical_slug, canonical_reasons = _canonical_repository_slug(profile, remote)
+    if canonical_reasons:
+        return {"org": None, "repository": None, "reasons": canonical_reasons}
+    slug = canonical_slug or _workspace_repository_slug(remote)
     scope = session_ctx.assess_repository_scope(
         workspace_slug=slug,
         allowed=allowed,
@@ -2386,9 +2439,24 @@ def _resolve(remote: str, host: str | None, org: str | None, repo: str | None):
     filled_org = False
     filled_repo = False
     if not org_explicit or not repo_explicit:
-        parsed = remote_repo_guard.parse_org_repo_from_remote_url(
-            _local_git_remote_url(remote)
-        )
+        parsed = None
+        # #741: for a cross-repository namespace, prefer the canonical root's
+        # own repository identity. `_local_git_remote_url` looks a remote up by
+        # *name*, but a target checkout commonly names its remote `origin`
+        # rather than `prgs`; that lookup then returns None and the omitted
+        # coordinates silently fell through to the REMOTES default target —
+        # i.e. a completely unrelated repository. `_canonical_repository_slug`
+        # probes the candidate remote names against the canonical root.
+        try:
+            canonical_slug, _reasons = _canonical_repository_slug(get_profile(), remote)
+        except Exception:
+            canonical_slug = None
+        if canonical_slug:
+            parsed = session_ctx.parse_repository_slug(canonical_slug)
+        if not parsed:
+            parsed = remote_repo_guard.parse_org_repo_from_remote_url(
+                _local_git_remote_url(remote)
+            )
         if parsed:
             if not org_explicit:
                 resolved_org = parsed[0]
@@ -2396,6 +2464,40 @@ def _resolve(remote: str, host: str | None, org: str | None, repo: str | None):
             if not repo_explicit:
                 resolved_repo = parsed[1]
                 filled_repo = True
+    # #741: explicit caller coordinates may *confirm* a cross-repository
+    # canonical binding but must never override it. Both-explicit coordinates
+    # short-circuit the #530 guard (remote_repo_guard.assess_remote_repo_match),
+    # so without this check a caller could name any repository and skip
+    # validation entirely. Unconfigured (single-repository) namespaces yield no
+    # canonical slug and are unaffected. An unresolvable configured root is not
+    # blocked here — reads must keep working; the fail-closed decision belongs
+    # to _enforce_canonical_repository_root at the mutation gate.
+    if org_explicit or repo_explicit:
+        try:
+            canonical_slug, _canonical_reasons = _canonical_repository_slug(
+                get_profile(), remote
+            )
+        except Exception:
+            canonical_slug = None
+        bound = (
+            session_ctx.parse_repository_slug(canonical_slug)
+            if canonical_slug
+            else None
+        )
+        if bound:
+            override = session_ctx.assess_repository_override(
+                requested_org=org,
+                requested_repo=repo,
+                bound_org=bound[0],
+                bound_repo=bound[1],
+            )
+            if override.get("block"):
+                raise RuntimeError(
+                    "Canonical repository binding guard (#741): "
+                    + "; ".join(override.get("reasons") or [])
+                    + ". Explicit org/repo may confirm the configured canonical "
+                    "repository binding but can never override it."
+                )
     _enforce_remote_repo_guard(
         remote,
         resolved_org,
@@ -3050,7 +3152,7 @@ def gitea_lock_issue(
         return blocked
 
     resolved_worktree = issue_lock_worktree.resolve_author_worktree_path(
-        worktree_path, PROJECT_ROOT
+        worktree_path, _canonical_local_git_root()
     )
     h, o, r = _resolve(remote, host, org, repo)
     active_lease_block = issue_lock_store.assess_same_issue_lease_conflict(
@@ -3352,7 +3454,7 @@ def gitea_create_pr(
     locked_worktree = lock_data.get("worktree_path")
 
     worktree_check = issue_lock_worktree.verify_pr_worktree_matches_lock(
-        locked_worktree, worktree_path, PROJECT_ROOT
+        locked_worktree, worktree_path, _canonical_local_git_root()
     )
     if worktree_check["block"]:
         raise ValueError(worktree_check["reasons"][0])
@@ -8482,13 +8584,24 @@ def gitea_merge_pr(
 
 
 def _local_git_remote_url(remote_name: str) -> str | None:
-    """Best-effort local ``git remote get-url`` for trust-gate corroboration."""
+    """Best-effort local ``git remote get-url`` for trust-gate corroboration.
+
+    #741: this runs in the **canonical target repository root**, not the
+    Gitea-Tools installation checkout. Every consumer of this function derives
+    *target repository identity* from it (``_resolve``, the #530 remote/repo
+    guard, the anti-stomp org/repo fill, ``_workspace_repository_slug``), so
+    running it in ``PROJECT_ROOT`` inverted those guards for a cross-repository
+    namespace: the genuinely bound target was rejected while Gitea-Tools was
+    accepted. Single-repository namespaces are unaffected —
+    :func:`_canonical_local_git_root` returns ``PROJECT_ROOT`` when no
+    cross-repository binding is configured.
+    """
     try:
         proc = subprocess.run(
             ["git", "remote", "get-url", remote_name],
             capture_output=True,
             text=True,
-            cwd=PROJECT_ROOT,
+            cwd=_canonical_local_git_root(),
         )
         if proc.returncode != 0:
             return None
@@ -8768,8 +8881,28 @@ def _delete_branch_repository_binding_block(
       (unproven target).
 
     Returns a structured block dict, or ``None`` when the target is authorized.
+
+    #739 F2: the trusted identity is the session's configured
+    ``canonical_repository_root`` when the namespace declares one. Deriving it
+    from ``_workspace_repository_slug`` alone reads the *installation* checkout
+    (``_local_git_remote_url`` runs in ``PROJECT_ROOT``, always Gitea-Tools),
+    which inverts the guard for a cross-repository namespace: the genuinely
+    bound target is rejected and Gitea-Tools is accepted. A configured root that
+    cannot be resolved fails closed rather than falling back to the install
+    identity; unconfigured namespaces keep the install-derived default.
     """
-    workspace_slug = _workspace_repository_slug(remote)
+    canonical_slug, canonical_reasons = _canonical_repository_slug(
+        get_profile(), remote
+    )
+    if canonical_reasons:
+        return {
+            "success": False,
+            "performed": False,
+            "required_permission": "gitea.branch.delete",
+            "reasons": canonical_reasons,
+            "blocker_kind": "repository_binding",
+        }
+    workspace_slug = canonical_slug or _workspace_repository_slug(remote)
     workspace_parts = (
         session_ctx.parse_repository_slug(workspace_slug) if workspace_slug else None
     )
@@ -9038,7 +9171,7 @@ def gitea_cleanup_merged_pr_branch(
         else f"origin/{target_branch}"
     )
     head_on_target = merged_cleanup_reconcile.is_head_ancestor_of_ref(
-        PROJECT_ROOT,
+        _canonical_local_git_root(),
         head_sha,
         target_ref,
     )
@@ -9073,7 +9206,7 @@ def gitea_cleanup_merged_pr_branch(
         repo=r,
         branch=head_branch,
         pr_number=pr_number,
-        project_root=PROJECT_ROOT,
+        project_root=_canonical_local_git_root(),
         auth=auth,
         base_api=base,
     )
@@ -9568,7 +9701,7 @@ def gitea_capture_branches_worktree_snapshot(
             "reasons": read_block,
             "permission_report": _permission_block_report("gitea.read"),
         }
-    root = PROJECT_ROOT
+    root = _canonical_local_git_root()
     if worktree_path:
         root = os.path.realpath(os.path.abspath(worktree_path))
         git_root = _get_git_root(root)
@@ -9678,14 +9811,14 @@ def gitea_reconcile_merged_cleanups(
                 h, o, r, auth, head_ref
             )
         head_on_master[int(pr["number"])] = merged_cleanup_reconcile.is_head_ancestor_of_ref(
-            PROJECT_ROOT, head_sha, master_ref
+            _canonical_local_git_root(), head_sha, master_ref
         )
 
     delete_capability_allowed = not _profile_operation_gate("gitea.branch.delete")
 
     # #534: discover reviewer scratch trees and active leases for those PRs.
     scratch_candidates = merged_cleanup_reconcile.discover_reviewer_scratch_worktrees(
-        PROJECT_ROOT
+        _canonical_local_git_root()
     )
     active_reviewer_leases: dict[int, bool] = {}
     pr_states: dict[int, dict] = {}
@@ -9711,7 +9844,7 @@ def gitea_reconcile_merged_cleanups(
         }
 
     report = merged_cleanup_reconcile.build_reconciliation_report(
-        project_root=PROJECT_ROOT,
+        project_root=_canonical_local_git_root(),
         closed_prs=merged_closed,
         open_prs=open_prs,
         remote_branch_exists=remote_branch_exists,
@@ -9751,7 +9884,7 @@ def gitea_reconcile_merged_cleanups(
                 repo=r,
                 branch=head_branch,
                 pr_number=pr_num_int,
-                project_root=PROJECT_ROOT,
+                project_root=_canonical_local_git_root(),
                 auth=auth,
                 base_api=base,
             )
@@ -9835,7 +9968,7 @@ def gitea_reconcile_merged_cleanups(
 
         if local_assessment.get("safe_to_remove_worktree"):
             result = merged_cleanup_reconcile.remove_local_worktree(
-                PROJECT_ROOT,
+                _canonical_local_git_root(),
                 head_branch,
                 worktree_path=local_assessment.get("worktree_path"),
             )
@@ -9845,7 +9978,7 @@ def gitea_reconcile_merged_cleanups(
         if not scratch.get("safe_to_remove_worktree"):
             continue
         result = merged_cleanup_reconcile.remove_reviewer_scratch_worktree(
-            PROJECT_ROOT, scratch.get("worktree_path") or ""
+            _canonical_local_git_root(), scratch.get("worktree_path") or ""
         )
         actions.append({"action": "remove_reviewer_scratch_worktree", **result})
 
@@ -9943,7 +10076,7 @@ def gitea_assess_already_landed_reconciliation(
 
     assessment = reconciliation_workflow.assess_open_pr_reconciliation(
         pr=pr,
-        project_root=PROJECT_ROOT,
+        project_root=_canonical_local_git_root(),
         remote=remote,
         target_branch=target_branch,
     )
@@ -10039,14 +10172,14 @@ def gitea_scan_already_landed_open_prs(
     }
 
     target_fetch = reconciliation_workflow.fetch_target_branch(
-        PROJECT_ROOT, remote, target_branch
+        _canonical_local_git_root(), remote, target_branch
     )
 
     candidates: list[dict] = []
     for pr in open_prs:
         assessment = reconciliation_workflow.assess_open_pr_reconciliation(
             pr=pr,
-            project_root=PROJECT_ROOT,
+            project_root=_canonical_local_git_root(),
             remote=remote,
             target_branch=target_branch,
             target_fetch=target_fetch,
@@ -10143,7 +10276,7 @@ def gitea_audit_worktree_cleanup(
         active_issue_branches.add(str(lock["branch_name"]).strip())
 
     report = worktree_cleanup_audit.audit_branches_directory(
-        PROJECT_ROOT,
+        _canonical_local_git_root(),
         open_pr_branches=open_pr_branches,
         active_issue_branches=active_issue_branches,
         now=datetime.now(timezone.utc),
@@ -10226,7 +10359,7 @@ def gitea_reconcile_already_landed_pr(
 
     assessment = already_landed_reconcile.assess_already_landed_reconciliation(
         pr=pr,
-        project_root=PROJECT_ROOT,
+        project_root=_canonical_local_git_root(),
         remote=remote,
         target_branch=target_branch,
     )
@@ -10431,7 +10564,7 @@ def gitea_reconcile_superseded_by_merged_pr(
     )
 
     target_fetch = already_landed_reconcile.fetch_target_branch(
-        PROJECT_ROOT, remote, target_branch
+        _canonical_local_git_root(), remote, target_branch
     )
     superseding_head_sha = (
         (superseding_pr.get("head") or {}).get("sha")
@@ -10441,7 +10574,7 @@ def gitea_reconcile_superseded_by_merged_pr(
     ancestor = None
     if target_fetch.get("success"):
         ancestor = already_landed_reconcile.is_head_ancestor_of_ref(
-            PROJECT_ROOT,
+            _canonical_local_git_root(),
             superseding_head_sha,
             target_fetch.get("target_ref") or f"{remote}/{target_branch}",
         )
@@ -14226,6 +14359,16 @@ def gitea_get_runtime_context(
         remote: Known instance — 'dadeschools' or 'prgs'.
         host: Override the Gitea host.
     """
+    # #739 F1: normalize the remote *before* any host lookup, identity
+    # resolution, or session seeding. ``remote`` defaults to 'dadeschools'
+    # across the whole tool surface, so a caller that omits it on a prgs-hosted
+    # namespace would otherwise pin the argument default: the identity lookup
+    # below would authenticate against the wrong host, and because first-bind is
+    # first-write-wins a later, correct ``gitea_whoami(remote="prgs")`` could not
+    # repair the binding. ``gitea_whoami`` has always normalized here; this is
+    # the same call, not a new policy. Explicit non-default remotes pass through
+    # untouched, and a dadeschools-hosted profile still resolves to dadeschools.
+    remote = _effective_remote(remote)
     profile = get_profile()
     config = gitea_config.load_config()
     reveal = _reveal_endpoints()
@@ -14403,13 +14546,23 @@ def gitea_assess_master_parity(
     Never mutates and makes no network calls. Read-only operations are never
     blocked by staleness; only mutating operations fail closed while stale.
 
+    The top-level ``startup_head``/``current_head``/``in_parity`` fields keep
+    their original meaning: the *Gitea-Tools server implementation* only. #739
+    F3 adds two separately labelled dimensions so a cross-repository namespace
+    can tell them apart — ``server_implementation`` (this installation, restated
+    under an explicit name) and ``target_repository`` (the configured canonical
+    target checkout and its last-known remote master). Only the server dimension
+    gates mutations.
+
     Returns:
         dict with 'in_parity', 'stale', 'restart_required', 'startup_head',
-        'current_head', 'mutation_gate_enforced', 'summary', 'reasons', and a
-        'report' recovery payload when stale.
+        'current_head', 'mutation_gate_enforced', 'summary', 'reasons',
+        'server_implementation', 'target_repository', and a 'report' recovery
+        payload when stale.
     """
     parity = _current_master_parity()
     enforced = not master_parity_gate.gate_disabled()
+    canonical_root, canonical_source = _configured_canonical_root()
     out = {
         "in_parity": parity["in_parity"],
         "stale": parity["stale"],
@@ -14421,6 +14574,17 @@ def gitea_assess_master_parity(
         "summary": master_parity_gate.format_parity(parity),
         "reasons": parity["reasons"],
         "process_root": PROJECT_ROOT,
+        "server_implementation": {
+            "installation_root": PROJECT_ROOT,
+            "startup_head": parity["startup_head"],
+            "current_head": parity["current_head"],
+            "stale": parity["stale"],
+            "determinable": parity["determinable"],
+        },
+        "target_repository": master_parity_gate.assess_target_repository_parity(
+            canonical_root=canonical_root,
+            source=canonical_source,
+        ),
     }
     if parity["stale"] and enforced:
         out["report"] = master_parity_gate.parity_report(parity)
@@ -15667,7 +15831,7 @@ def gitea_update_pr_branch_by_merge(
 
     control_clean = True
     try:
-        porcelain = _get_workspace_porcelain(PROJECT_ROOT)
+        porcelain = _get_workspace_porcelain(_canonical_local_git_root())
         # Untracked-only dirt is ignored; tracked edits contaminate control.
         tracked_dirty = [
             line for line in (porcelain or "").splitlines()

master_parity_gate.py

@@ -166,3 +166,128 @@ def format_parity(assessment: dict) -> str:
     if not assessment.get("determinable"):
         return "parity indeterminate (baseline or current HEAD unknown)"
     return f"in parity at {_short(assessment.get('current_head'))}"
+
+
+# ---------------------------------------------------------------------------
+# Target-repository parity (#739 F3)
+#
+# Everything above measures ONE dimension: the Gitea-Tools server's own
+# implementation commit, comparing the SHA this process was loaded from against
+# the SHA now on disk at PROJECT_ROOT. That is deliberate and is left untouched
+# — it is what proves the in-memory capability gates are current.
+#
+# It is not, however, a statement about the repository a cross-repository
+# namespace actually mutates. The assessment below is a separate, separately
+# labelled dimension for the configured canonical target repository. It never
+# feeds the mutation gate and never changes startup_head/current_head.
+# ---------------------------------------------------------------------------
+
+DEFAULT_TARGET_TRACKING_REF = "refs/remotes/origin/master"
+
+
+def _git_capture(root: str, *args: str) -> str | None:
+    """Run a read-only git command in *root*; ``None`` on any failure.
+
+    Deliberately does not honour ``GITEA_TEST_CURRENT_HEAD``: that override
+    exists to pin the *server's* HEAD, and applying it here would make a target
+    repository silently report the server's forced SHA.
+    """
+    if not root:
+        return None
+    try:
+        res = subprocess.run(
+            ["git", "-C", root, *args],
+            capture_output=True,
+            text=True,
+            check=False,
+        )
+    except Exception:
+        return None
+    if res.returncode != 0:
+        return None
+    return (res.stdout or "").strip() or None
+
+
+def assess_target_repository_parity(
+    *,
+    canonical_root: str | None,
+    source: str | None,
+    tracking_ref: str = DEFAULT_TARGET_TRACKING_REF,
+) -> dict:
+    """Assess the configured cross-repository target checkout.
+
+    Reports the target's canonical root, repository identity, checked-out
+    commit, and last-known remote master commit, plus whether the checkout is
+    behind that ref. No network call is made: the remote side is read from the
+    existing remote-tracking ref, so a target that has never been fetched is
+    reported as indeterminate rather than guessed at.
+
+    An unconfigured namespace is ``configured=False`` and never ``stale`` — the
+    single-repository default has no second dimension to be stale about. A
+    configured root that cannot be read is ``determinable=False`` with reasons.
+    """
+    result = {
+        "configured": bool(canonical_root),
+        "canonical_repository_root": None,
+        "source": source,
+        "repository_slug": None,
+        "checkout_head": None,
+        "tracking_ref": tracking_ref,
+        "remote_tracking_head": None,
+        "determinable": False,
+        "stale": False,
+        "reasons": [],
+    }
+    if not canonical_root:
+        result["determinable"] = True
+        return result
+
+    result["canonical_repository_root"] = canonical_root
+    if not os.path.isdir(canonical_root):
+        result["reasons"].append(
+            f"configured canonical repository root '{canonical_root}' "
+            f"does not exist or is not a directory"
+        )
+        return result
+
+    toplevel = _git_capture(canonical_root, "rev-parse", "--show-toplevel")
+    if not toplevel:
+        result["reasons"].append(
+            f"configured canonical repository root '{canonical_root}' "
+            f"is not a git checkout"
+        )
+        return result
+
+    head = _git_capture(canonical_root, "rev-parse", "HEAD")
+    if not head:
+        result["reasons"].append(
+            f"target repository HEAD could not be read at '{canonical_root}'"
+        )
+        return result
+    result["checkout_head"] = head
+    result["determinable"] = True
+
+    remote_url = _git_capture(canonical_root, "remote", "get-url", "origin")
+    if remote_url:
+        # Local import keeps this module dependency-light for its startup role.
+        import remote_repo_guard
+
+        parsed = remote_repo_guard.parse_org_repo_from_remote_url(remote_url)
+        if parsed:
+            result["repository_slug"] = f"{parsed[0]}/{parsed[1]}"
+    if not result["repository_slug"]:
+        result["reasons"].append(
+            "target repository identity could not be derived from its git remote"
+        )
+
+    tracking_head = _git_capture(canonical_root, "rev-parse", tracking_ref)
+    if not tracking_head:
+        result["reasons"].append(
+            f"remote-tracking ref '{tracking_ref}' is unknown in the target "
+            f"checkout; target staleness is indeterminate (no fetch is "
+            f"performed by this assessment)"
+        )
+        return result
+    result["remote_tracking_head"] = tracking_head
+    result["stale"] = tracking_head != head
+    return result

tests/test_cross_repo_canonical_consumption.py

@@ -0,0 +1,704 @@
+"""Complete canonical-root consumption for cross-repository MCP namespaces.
+
+#706 introduced an immutable, configured ``canonical_repository_root`` and
+routed the #274 filesystem guards and the session repository *slug* through it.
+Three consumption paths were left behind, and this module drives each one
+through its production entry point:
+
+* **A — remote initialization.** ``gitea_get_runtime_context`` never normalized
+  its ``remote`` argument, while ``gitea_whoami`` did. A fresh process whose
+  first native call is the runtime-context path therefore pinned the
+  ``dadeschools`` argument default instead of the profile's configured remote,
+  and — because first-bind is first-write-wins — no later correct call could
+  repair it.
+
+* **C — reconciler branch deletion.** The delete-branch repository-binding
+  guard derived its expected slug from ``_workspace_repository_slug``, which
+  reads the git remote of the *installation* checkout (always Gitea-Tools),
+  rather than from the session's configured canonical root.
+
+* **D — parity evidence.** ``gitea_assess_master_parity`` proves Gitea-Tools
+  *server implementation* parity only, which is intentional. It carried no
+  target-repository dimension at all, so a cross-repository namespace had no
+  evidence that its target checkout was current. The existing
+  ``startup_head``/``current_head`` semantics are preserved unchanged and the
+  target-repository assessment is reported under separately labelled fields.
+
+Groups B and E assert *intentional* behaviour (the #274 guards already consume
+the canonical root; the configuration surface already validates a
+repository-specific namespace) so that a regression in either is caught.
+
+Real git repositories are used throughout; no network calls are made.
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import subprocess
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+from unittest.mock import patch
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+import canonical_repository_root as crr  # noqa: E402
+import gitea_config  # noqa: E402
+import gitea_mcp_server as srv  # noqa: E402
+import master_parity_gate  # noqa: E402
+import mcp_server  # noqa: E402
+import namespace_workspace_binding as nwb  # noqa: E402
+import session_context_binding as session_ctx  # noqa: E402
+
+INSTALL_ORG = "Scaled-Tech-Consulting"
+INSTALL_REPO = "Gitea-Tools"
+INSTALL_SLUG = f"{INSTALL_ORG}/{INSTALL_REPO}"
+INSTALL_URL = f"https://gitea.prgs.cc/{INSTALL_SLUG}.git"
+
+TARGET_ORG = "Scaled-Tech-Consulting"
+TARGET_REPO = "mcp-control-plane"
+TARGET_SLUG = f"{TARGET_ORG}/{TARGET_REPO}"
+TARGET_URL = f"https://gitea.prgs.cc/{TARGET_SLUG}.git"
+
+
+def _git(cwd: str, *args: str) -> str:
+    res = subprocess.run(
+        ["git", "-C", cwd, *args], capture_output=True, text=True, check=True
+    )
+    return res.stdout.strip()
+
+
+def _init_repo(path: Path, remote_url: str, *, remote_name: str = "origin") -> str:
+    path.mkdir(parents=True, exist_ok=True)
+    _git(str(path), "init", "-q")
+    _git(str(path), "config", "user.email", "[email protected]")
+    _git(str(path), "config", "user.name", "Test")
+    _git(str(path), "remote", "add", remote_name, remote_url)
+    (path / "README.md").write_text("seed\n")
+    _git(str(path), "add", "README.md")
+    _git(str(path), "commit", "-q", "-m", "seed")
+    return os.path.realpath(str(path))
+
+
+# ---------------------------------------------------------------------------
+# Shared profile/config construction
+# ---------------------------------------------------------------------------
+_AUTHOR_OPS = [
+    "gitea.read",
+    "gitea.issue.create",
+    "gitea.issue.comment",
+    "gitea.pr.create",
+    "gitea.pr.comment",
+    "gitea.branch.create",
+    "gitea.branch.push",
+    "gitea.repo.commit",
+]
+_AUTHOR_FORBIDDEN = [
+    "gitea.pr.approve",
+    "gitea.pr.merge",
+    "gitea.pr.request_changes",
+]
+# A profile that may approve or merge must forbid authoring (gitea_config's
+# reviewer-identity deadlock rule).
+_REVIEWER_OPS = [
+    "gitea.read",
+    "gitea.pr.approve",
+    "gitea.pr.request_changes",
+    "gitea.pr.comment",
+    "gitea.issue.comment",
+]
+_REVIEWER_FORBIDDEN = ["gitea.pr.create", "gitea.branch.push", "gitea.pr.merge"]
+_MERGER_OPS = ["gitea.read", "gitea.pr.merge", "gitea.pr.comment"]
+_MERGER_FORBIDDEN = [
+    "gitea.pr.create",
+    "gitea.branch.push",
+    "gitea.pr.approve",
+    "gitea.pr.request_changes",
+]
+_RECONCILER_OPS = [
+    "gitea.read",
+    "gitea.pr.close",
+    "gitea.pr.comment",
+    "gitea.branch.delete",
+]
+_RECONCILER_FORBIDDEN = [
+    "gitea.pr.create",
+    "gitea.branch.push",
+    "gitea.pr.approve",
+    "gitea.pr.merge",
+    "gitea.pr.request_changes",
+]
+
+_ROLE_MATRIX = {
+    "author": (_AUTHOR_OPS, _AUTHOR_FORBIDDEN),
+    "reviewer": (_REVIEWER_OPS, _REVIEWER_FORBIDDEN),
+    "merger": (_MERGER_OPS, _MERGER_FORBIDDEN),
+    "reconciler": (_RECONCILER_OPS, _RECONCILER_FORBIDDEN),
+}
+
+
+def _profile(
+    role: str,
+    *,
+    canonical_root: str | None = None,
+    allowed_repositories: list[str] | None = None,
+    username: str = "jcwalker3",
+) -> dict:
+    allowed, forbidden = _ROLE_MATRIX[role]
+    profile = {
+        "enabled": True,
+        "context": "prgs",
+        "role": role,
+        "username": username,
+        "base_url": "https://gitea.prgs.cc",
+        "auth": {"type": "env", "name": f"GITEA_TOKEN_PRGS_{role.upper()}"},
+        "allowed_operations": list(allowed),
+        "forbidden_operations": list(forbidden),
+        "execution_profile": f"prgs-{role}",
+    }
+    if canonical_root is not None:
+        profile["canonical_repository_root"] = canonical_root
+    if allowed_repositories is not None:
+        profile["allowed_repositories"] = list(allowed_repositories)
+    return profile
+
+
+def _config(profiles: dict) -> dict:
+    return {
+        "version": 2,
+        "rules": {"allow_runtime_switching": True},
+        "contexts": {
+            "prgs": {
+                "enabled": True,
+                "gitea": {"enabled": True, "base_url": "https://gitea.prgs.cc"},
+            },
+            "mdcps": {
+                "enabled": True,
+                "gitea": {
+                    "enabled": True,
+                    "base_url": "https://gitea.dadeschools.net",
+                },
+            },
+        },
+        "profiles": profiles,
+    }
+
+
+class _ServerHarness(unittest.TestCase):
+    """Temp profiles.json + pinned install remote + no network."""
+
+    def setUp(self):
+        self._dir = tempfile.TemporaryDirectory()
+        self.tmp = self._dir.name
+        self.config_path = os.path.join(self.tmp, "profiles.json")
+        session_ctx._reset_session_context_for_testing()
+        gitea_config._active_profile_override = None
+        mcp_server._IDENTITY_CACHE.clear()
+        srv._MUTATION_AUTHORITY = None
+        # The install checkout's remote is Gitea-Tools regardless of the
+        # developer's layout; pin it so "install-derived" is deterministic.
+        self._remote_url = patch.object(
+            srv, "_local_git_remote_url", side_effect=self._install_remote_url
+        )
+        self._remote_url.start()
+
+    def tearDown(self):
+        self._remote_url.stop()
+        session_ctx._reset_session_context_for_testing()
+        gitea_config._active_profile_override = None
+        mcp_server._IDENTITY_CACHE.clear()
+        srv._MUTATION_AUTHORITY = None
+        self._dir.cleanup()
+
+    def _install_remote_url(self, remote_name):
+        return INSTALL_URL if remote_name in ("prgs", "origin") else None
+
+    def _write_config(self, profiles: dict) -> None:
+        with open(self.config_path, "w", encoding="utf-8") as fh:
+            fh.write(json.dumps(_config(profiles)))
+
+    def _env(self, profile_name: str, **extra) -> dict:
+        env = {
+            "GITEA_MCP_CONFIG": self.config_path,
+            "GITEA_MCP_PROFILE": profile_name,
+            "GITEA_TOKEN_PRGS_AUTHOR": "t",
+            "GITEA_TOKEN_PRGS_REVIEWER": "t",
+            "GITEA_TOKEN_PRGS_MERGER": "t",
+            "GITEA_TOKEN_PRGS_RECONCILER": "t",
+        }
+        env.update(extra)
+        return env
+
+    def _api(self, method, url, header):
+        return {
+            "login": "jcwalker3",
+            "full_name": "Test",
+            "id": 1,
+            "email": "[email protected]",
+        }
+
+    def _live(self):
+        return patch("gitea_mcp_server.api_request", side_effect=self._api)
+
+
+# ===========================================================================
+# A. Remote initialization
+# ===========================================================================
+class TestRemoteInitializationFirstCall(_ServerHarness):
+    """A prgs namespace must never pin the dadeschools argument default."""
+
+    def setUp(self):
+        super().setUp()
+        self._write_config(
+            {"prgs-author": _profile("author", allowed_repositories=[INSTALL_SLUG])}
+        )
+
+    def test_runtime_context_first_call_does_not_bind_default_remote(self):
+        """Runtime-context as the FIRST native call, relying on the default."""
+        with patch.dict(os.environ, self._env("prgs-author"), clear=False), self._live():
+            srv.gitea_get_runtime_context()
+            ctx = session_ctx.get_session_context()
+        self.assertIsNotNone(ctx, "first call must establish a session binding")
+        self.assertEqual(ctx["remote"], "prgs")
+        self.assertEqual(ctx["host"], "gitea.prgs.cc")
+        self.assertEqual(ctx["org"], INSTALL_ORG)
+        self.assertEqual(ctx["repository"], INSTALL_REPO)
+
+    def test_runtime_context_first_call_reports_effective_remote(self):
+        with patch.dict(os.environ, self._env("prgs-author"), clear=False), self._live():
+            result = srv.gitea_get_runtime_context()
+        self.assertEqual(result["remote"], "prgs")
+
+    def test_whoami_first_call_remains_correct(self):
+        """Control: the already-normalizing path is unchanged."""
+        with patch.dict(os.environ, self._env("prgs-author"), clear=False), self._live():
+            srv.gitea_whoami()
+            ctx = session_ctx.get_session_context()
+        self.assertEqual(ctx["remote"], "prgs")
+        self.assertEqual(ctx["host"], "gitea.prgs.cc")
+
+    def test_explicit_remote_argument_still_honoured(self):
+        """Normalization only fills the default; explicit values are untouched."""
+        with patch.dict(os.environ, self._env("prgs-author"), clear=False), self._live():
+            result = srv.gitea_get_runtime_context(remote="prgs")
+        self.assertEqual(result["remote"], "prgs")
+
+    def test_mdcps_profile_default_is_not_rewritten_to_prgs(self):
+        """A dadeschools-hosted profile keeps the dadeschools remote."""
+        profile = _profile("author", allowed_repositories=[INSTALL_SLUG])
+        profile["context"] = "mdcps"
+        profile["base_url"] = "https://gitea.dadeschools.net"
+        self._write_config({"prgs-author": profile})
+        with patch.dict(os.environ, self._env("prgs-author"), clear=False), self._live():
+            result = srv.gitea_get_runtime_context()
+        self.assertEqual(result["remote"], "dadeschools")
+
+
+# ===========================================================================
+# B. Remote/repository guard (intentional behaviour — regression fence)
+# ===========================================================================
+class TestCanonicalRootGuardBinding(_ServerHarness):
+    def setUp(self):
+        super().setUp()
+        self.target_root = _init_repo(Path(self.tmp) / "mcp-control-plane", TARGET_URL)
+        self.install_root = _init_repo(Path(self.tmp) / "install", INSTALL_URL)
+
+    def test_canonical_target_root_resolves_to_target_slug(self):
+        got = crr.assess_canonical_repository_root(
+            configured_value=self.target_root,
+            source="profile.canonical_repository_root",
+            expected_slug=None,
+            process_project_root=self.install_root,
+            remote="prgs",
+            require_binding=True,
+        )
+        self.assertFalse(got.get("block"), got.get("reasons"))
+        self.assertEqual(got["resolved_slug"], TARGET_SLUG)
+
+    def test_install_root_identity_remains_gitea_tools(self):
+        got = crr.assess_canonical_repository_root(
+            configured_value=None,
+            source=None,
+            expected_slug=None,
+            process_project_root=self.install_root,
+            remote="prgs",
+        )
+        self.assertEqual(
+            os.path.realpath(got["canonical_repo_root"]), self.install_root
+        )
+
+    def test_guards_validate_against_canonical_target_root(self):
+        ctx = nwb.resolve_namespace_mutation_context(
+            role_kind="author",
+            worktree_path=None,
+            process_project_root=self.install_root,
+            configured_canonical_root=self.target_root,
+        )
+        self.assertEqual(
+            os.path.realpath(ctx["canonical_repo_root"]), self.target_root
+        )
+
+    def test_explicit_coordinates_cannot_override_canonical_binding(self):
+        """Explicit org/repo may confirm, never authorize, a binding."""
+        confirm = session_ctx.assess_repository_override(
+            requested_org=TARGET_ORG,
+            requested_repo=TARGET_REPO,
+            bound_org=TARGET_ORG,
+            bound_repo=TARGET_REPO,
+        )
+        self.assertFalse(confirm.get("block"))
+        override = session_ctx.assess_repository_override(
+            requested_org=TARGET_ORG,
+            requested_repo=TARGET_REPO,
+            bound_org=INSTALL_ORG,
+            bound_repo=INSTALL_REPO,
+        )
+        self.assertTrue(override.get("block"))
+
+    def test_gitea_tools_rooted_namespace_cannot_reach_target_repository(self):
+        """No canonical root configured → session stays pinned to Gitea-Tools."""
+        profile = _profile("author", allowed_repositories=[INSTALL_SLUG])
+        with patch.dict(os.environ, {}, clear=False):
+            os.environ.pop(crr.CANONICAL_ROOT_ENV, None)
+            resolved = srv._trusted_session_repository(
+                profile, "prgs", for_mutation=True
+            )
+        self.assertEqual(resolved["repository"], INSTALL_REPO)
+        self.assertNotEqual(resolved["repository"], TARGET_REPO)
+
+    def test_target_rooted_namespace_binds_target_repository(self):
+        profile = _profile(
+            "author",
+            canonical_root=self.target_root,
+            allowed_repositories=[TARGET_SLUG],
+        )
+        resolved = srv._trusted_session_repository(profile, "prgs", for_mutation=True)
+        self.assertEqual(resolved["org"], TARGET_ORG)
+        self.assertEqual(resolved["repository"], TARGET_REPO)
+
+
+# ===========================================================================
+# C. Reconciler branch deletion
+# ===========================================================================
+class TestDeleteBranchRepositoryBinding(_ServerHarness):
+    """The binding guard must consult the canonical root, not PROJECT_ROOT.
+
+    No branch is ever deleted here: only the pre-deletion binding guard is
+    exercised.
+    """
+
+    def setUp(self):
+        super().setUp()
+        self.target_root = _init_repo(Path(self.tmp) / "mcp-control-plane", TARGET_URL)
+        self._write_config(
+            {
+                "prgs-reconciler": _profile(
+                    "reconciler",
+                    canonical_root=self.target_root,
+                    allowed_repositories=[TARGET_SLUG],
+                ),
+                "gt-reconciler": _profile(
+                    "reconciler", allowed_repositories=[INSTALL_SLUG]
+                ),
+            }
+        )
+
+    def test_target_rooted_reconciler_validates_target_deletion(self):
+        with patch.dict(os.environ, self._env("prgs-reconciler"), clear=False):
+            block = srv._delete_branch_repository_binding_block(
+                "prgs", org=TARGET_ORG, repo=TARGET_REPO
+            )
+        self.assertIsNone(block, block)
+
+    def test_target_rooted_reconciler_fails_closed_for_install_repository(self):
+        with patch.dict(os.environ, self._env("prgs-reconciler"), clear=False):
+            block = srv._delete_branch_repository_binding_block(
+                "prgs", org=INSTALL_ORG, repo=INSTALL_REPO
+            )
+        self.assertIsNotNone(block)
+        self.assertEqual(block["blocker_kind"], "repository_binding")
+        self.assertFalse(block["performed"])
+
+    def test_install_rooted_reconciler_fails_closed_for_target_repository(self):
+        with patch.dict(os.environ, self._env("gt-reconciler"), clear=False):
+            os.environ.pop(crr.CANONICAL_ROOT_ENV, None)
+            block = srv._delete_branch_repository_binding_block(
+                "prgs", org=TARGET_ORG, repo=TARGET_REPO
+            )
+        self.assertIsNotNone(block)
+        self.assertEqual(block["blocker_kind"], "repository_binding")
+
+    def test_env_configured_canonical_root_is_honoured(self):
+        env = self._env("gt-reconciler")
+        env[crr.CANONICAL_ROOT_ENV] = self.target_root
+        with patch.dict(os.environ, env, clear=False):
+            allowed = srv._delete_branch_repository_binding_block(
+                "prgs", org=TARGET_ORG, repo=TARGET_REPO
+            )
+            blocked = srv._delete_branch_repository_binding_block(
+                "prgs", org=INSTALL_ORG, repo=INSTALL_REPO
+            )
+        self.assertIsNone(allowed, allowed)
+        self.assertIsNotNone(blocked)
+
+    def test_unresolvable_canonical_root_fails_closed(self):
+        env = self._env("gt-reconciler")
+        env[crr.CANONICAL_ROOT_ENV] = os.path.join(self.tmp, "does-not-exist")
+        with patch.dict(os.environ, env, clear=False):
+            block = srv._delete_branch_repository_binding_block(
+                "prgs", org=TARGET_ORG, repo=TARGET_REPO
+            )
+        self.assertIsNotNone(block)
+        self.assertEqual(block["blocker_kind"], "repository_binding")
+
+    def test_no_request_parameter_can_override_canonical_identity(self):
+        """Every explicit coordinate that is not the canonical target is
+        refused; none of them can *establish* the binding."""
+        # Both repositories share an org, so a wrong *org* case must name a
+        # genuinely different owner to be meaningful.
+        cases = [
+            (INSTALL_ORG, INSTALL_REPO),
+            (TARGET_ORG, INSTALL_REPO),
+            (TARGET_ORG, "some-other-repo"),
+            ("someone-else", TARGET_REPO),
+        ]
+        with patch.dict(os.environ, self._env("prgs-reconciler"), clear=False):
+            for org, repo in cases:
+                with self.subTest(org=org, repo=repo):
+                    block = srv._delete_branch_repository_binding_block(
+                        "prgs", org=org, repo=repo
+                    )
+                    self.assertIsNotNone(block, f"{org}/{repo} must fail closed")
+
+
+# ===========================================================================
+# D. Parity semantics
+# ===========================================================================
+class TestTargetRepositoryParityAssessment(unittest.TestCase):
+    """Server-implementation parity is preserved; target parity is additive."""
+
+    def setUp(self):
+        self._dir = tempfile.TemporaryDirectory()
+        self.tmp = self._dir.name
+
+    def tearDown(self):
+        self._dir.cleanup()
+
+    def _target(self) -> str:
+        return _init_repo(Path(self.tmp) / "mcp-control-plane", TARGET_URL)
+
+    def test_unconfigured_target_is_reported_not_stale(self):
+        got = master_parity_gate.assess_target_repository_parity(
+            canonical_root=None, source=None
+        )
+        self.assertFalse(got["configured"])
+        self.assertFalse(got["stale"])
+        self.assertIsNone(got["canonical_repository_root"])
+
+    def test_configured_target_reports_checkout_head_and_slug(self):
+        root = self._target()
+        head = _git(root, "rev-parse", "HEAD")
+        got = master_parity_gate.assess_target_repository_parity(
+            canonical_root=root, source="profile.canonical_repository_root"
+        )
+        self.assertTrue(got["configured"])
+        self.assertEqual(got["canonical_repository_root"], root)
+        self.assertEqual(got["checkout_head"], head)
+        self.assertEqual(got["repository_slug"], TARGET_SLUG)
+
+    def test_target_stale_when_remote_tracking_ref_is_ahead(self):
+        root = self._target()
+        head = _git(root, "rev-parse", "HEAD")
+        # Simulate a fetched remote-tracking ref that has advanced.
+        _git(root, "checkout", "-q", "-b", "advanced")
+        (Path(root) / "next.md").write_text("next\n")
+        _git(root, "add", "next.md")
+        _git(root, "commit", "-q", "-m", "advance")
+        advanced = _git(root, "rev-parse", "HEAD")
+        _git(root, "update-ref", "refs/remotes/origin/master", advanced)
+        _git(root, "checkout", "-q", "--detach", head)
+        got = master_parity_gate.assess_target_repository_parity(
+            canonical_root=root, source="profile.canonical_repository_root"
+        )
+        self.assertEqual(got["checkout_head"], head)
+        self.assertEqual(got["remote_tracking_head"], advanced)
+        self.assertTrue(got["stale"])
+
+    def test_missing_root_is_not_determinable_and_fails_closed(self):
+        got = master_parity_gate.assess_target_repository_parity(
+            canonical_root=os.path.join(self.tmp, "absent"),
+            source="profile.canonical_repository_root",
+        )
+        self.assertTrue(got["configured"])
+        self.assertFalse(got["determinable"])
+        self.assertTrue(got["reasons"])
+
+
+class TestParityToolEvidenceDimensions(_ServerHarness):
+    def setUp(self):
+        super().setUp()
+        self.target_root = _init_repo(Path(self.tmp) / "mcp-control-plane", TARGET_URL)
+        self._write_config(
+            {
+                "prgs-author": _profile(
+                    "author",
+                    canonical_root=self.target_root,
+                    allowed_repositories=[TARGET_SLUG],
+                )
+            }
+        )
+
+    def test_existing_server_parity_semantics_are_unchanged(self):
+        with patch.dict(os.environ, self._env("prgs-author"), clear=False):
+            result = srv.gitea_assess_master_parity(remote="prgs")
+        # startup_head/current_head keep their Gitea-Tools implementation
+        # meaning and must not be redefined to the target repository.
+        self.assertEqual(result["process_root"], srv.PROJECT_ROOT)
+        self.assertEqual(
+            result["startup_head"], srv._STARTUP_PARITY.get("startup_head")
+        )
+        self.assertIn("in_parity", result)
+
+    def test_evidence_distinguishes_server_and_target_dimensions(self):
+        with patch.dict(os.environ, self._env("prgs-author"), clear=False):
+            result = srv.gitea_assess_master_parity(remote="prgs")
+        server = result["server_implementation"]
+        self.assertEqual(server["installation_root"], srv.PROJECT_ROOT)
+        self.assertEqual(server["current_head"], result["current_head"])
+        self.assertIn("stale", server)
+
+        target = result["target_repository"]
+        self.assertTrue(target["configured"])
+        self.assertEqual(target["canonical_repository_root"], self.target_root)
+        self.assertEqual(target["repository_slug"], TARGET_SLUG)
+        self.assertEqual(
+            target["checkout_head"], _git(self.target_root, "rev-parse", "HEAD")
+        )
+        self.assertIn("stale", target)
+
+    def test_unconfigured_namespace_reports_target_as_unconfigured(self):
+        self._write_config(
+            {"prgs-author": _profile("author", allowed_repositories=[INSTALL_SLUG])}
+        )
+        env = self._env("prgs-author")
+        with patch.dict(os.environ, env, clear=False):
+            os.environ.pop(crr.CANONICAL_ROOT_ENV, None)
+            result = srv.gitea_assess_master_parity(remote="prgs")
+        self.assertFalse(result["target_repository"]["configured"])
+
+
+# ===========================================================================
+# E. Startup / configuration validation for a candidate namespace set
+# ===========================================================================
+class TestCandidateNamespaceConfiguration(_ServerHarness):
+    """Four repository-specific profiles for the target repository."""
+
+    def setUp(self):
+        super().setUp()
+        self.target_root = _init_repo(Path(self.tmp) / "mcp-control-plane", TARGET_URL)
+        self.profiles = {
+            f"mcpcp-{role}": _profile(
+                role,
+                canonical_root=self.target_root,
+                allowed_repositories=[TARGET_SLUG],
+            )
+            for role in ("author", "reviewer", "merger", "reconciler")
+        }
+        self._write_config(self.profiles)
+
+    def test_configuration_audit_succeeds(self):
+        with patch.dict(os.environ, self._env("mcpcp-author"), clear=False):
+            audit = srv.gitea_audit_config()
+        self.assertTrue(audit.get("configured"))
+        names = {row["name"] for row in audit["profiles"]}
+        self.assertEqual(names, set(self.profiles))
+
+    def test_no_inline_credentials_are_present(self):
+        raw = json.loads(Path(self.config_path).read_text())
+        for name, profile in raw["profiles"].items():
+            with self.subTest(profile=name):
+                self.assertNotIn("token", profile)
+                self.assertNotIn("password", profile)
+                self.assertNotIn("secret", profile)
+                self.assertIn(profile["auth"]["type"], ("env", "keychain"))
+
+    def test_bind_time_validation_succeeds_for_target_repository(self):
+        for name, profile in self.profiles.items():
+            with self.subTest(profile=name):
+                resolved = srv._trusted_session_repository(
+                    profile, "prgs", for_mutation=True
+                )
+                self.assertEqual(resolved["reasons"], [])
+                self.assertEqual(resolved["org"], TARGET_ORG)
+                self.assertEqual(resolved["repository"], TARGET_REPO)
+
+    def test_wrong_repository_root_fails_closed(self):
+        wrong_root = _init_repo(Path(self.tmp) / "wrong", INSTALL_URL)
+        profile = _profile(
+            "author", canonical_root=wrong_root, allowed_repositories=[TARGET_SLUG]
+        )
+        resolved = srv._trusted_session_repository(profile, "prgs", for_mutation=True)
+        self.assertIsNone(resolved["repository"])
+        self.assertTrue(resolved["reasons"])
+
+    def test_existing_install_profiles_are_unchanged_in_behaviour(self):
+        profile = _profile("author", allowed_repositories=[INSTALL_SLUG])
+        resolved = srv._trusted_session_repository(profile, "prgs", for_mutation=True)
+        self.assertEqual(resolved["org"], INSTALL_ORG)
+        self.assertEqual(resolved["repository"], INSTALL_REPO)
+
+    def _denied(self, profile: dict, operation: str) -> bool:
+        ok, _ = gitea_config.check_operation(
+            operation,
+            profile["allowed_operations"],
+            profile["forbidden_operations"],
+        )
+        return not ok
+
+    def test_role_separation_is_enforced(self):
+        expectations = {
+            "author": [
+                "gitea.pr.approve",
+                "gitea.pr.merge",
+                "gitea.pr.request_changes",
+            ],
+            "reviewer": ["gitea.pr.create", "gitea.branch.push", "gitea.pr.merge"],
+            "merger": [
+                "gitea.pr.create",
+                "gitea.branch.push",
+                "gitea.pr.approve",
+                "gitea.pr.request_changes",
+            ],
+            "reconciler": [
+                "gitea.pr.create",
+                "gitea.branch.push",
+                "gitea.pr.approve",
+                "gitea.pr.merge",
+                "gitea.pr.request_changes",
+            ],
+        }
+        for role, denied_ops in expectations.items():
+            profile = self.profiles[f"mcpcp-{role}"]
+            for op in denied_ops:
+                with self.subTest(role=role, operation=op):
+                    self.assertTrue(
+                        self._denied(profile, op),
+                        f"{role} must not be permitted {op}",
+                    )
+
+    def test_each_role_retains_its_own_capability(self):
+        permitted = {
+            "author": "gitea.pr.create",
+            "reviewer": "gitea.pr.approve",
+            "merger": "gitea.pr.merge",
+            "reconciler": "gitea.branch.delete",
+        }
+        for role, op in permitted.items():
+            with self.subTest(role=role, operation=op):
+                self.assertFalse(self._denied(self.profiles[f"mcpcp-{role}"], op))
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_issue_741_canonical_root_consumers.py

@@ -0,0 +1,768 @@
+"""Complete PROJECT_ROOT elimination in cross-repository MCP operations (#741).
+
+#706 introduced the immutable ``canonical_repository_root``; #739/#740 routed
+three consumption paths through it. This module covers the paths #740 left
+behind, whose shape is uniform: the *filesystem* guards were migrated to the
+canonical root, but *repository identity* still bottomed out in
+``_local_git_remote_url``'s hardcoded ``cwd=PROJECT_ROOT`` — always the
+Gitea-Tools installation checkout.
+
+The consequences asserted here:
+
+* **Identity inversion.** ``_resolve``, the #530 remote/repo guard and the
+  anti-stomp org/repo fill all derived the *target* repository from the
+  *install* checkout, so a cross-repository namespace resolved Gitea-Tools
+  coordinates while its branch/parity facts came from the target repo.
+* **Guard disagreement.** ``_verify_role_mutation_workspace`` omitted
+  ``configured_canonical_root``, so the #274 branches-only / worktree-membership
+  guards validated ``Gitea-Tools/branches/`` rather than the bound target.
+* **Explicit-coordinate override.** Both-explicit ``org``/``repo`` short-circuit
+  ``assess_remote_repo_match``, so caller coordinates bypassed validation
+  entirely rather than merely *confirming* the binding.
+* **Configuration fail-open.** ``_flatten_identity`` silently dropped
+  ``canonical_repository_root``, so a v2-``environments`` namespace fell back to
+  the install root; the v1 path never validated the field at all.
+
+A role-by-operation matrix drives author, reviewer, merger and reconciler
+against: correct cross-repository target, wrong repository, wrong worktree,
+explicit matching coordinates, explicit mismatched coordinates, missing
+canonical root, invalid canonical root, immutable binding after first bind, and
+request-override attempts.
+
+Real git repositories are used throughout. No network calls are made, no branch
+is deleted, and no merge is performed.
+"""
+
+from __future__ import annotations
+
+import json
+import os
+import subprocess
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+from unittest.mock import patch
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+import canonical_repository_root as crr  # noqa: E402
+import gitea_config  # noqa: E402
+import gitea_mcp_server as srv  # noqa: E402
+import mcp_server  # noqa: E402
+import session_context_binding as session_ctx  # noqa: E402
+
+INSTALL_ORG = "Scaled-Tech-Consulting"
+INSTALL_REPO = "Gitea-Tools"
+INSTALL_SLUG = f"{INSTALL_ORG}/{INSTALL_REPO}"
+INSTALL_URL = f"https://gitea.prgs.cc/{INSTALL_SLUG}.git"
+
+TARGET_ORG = "Scaled-Tech-Consulting"
+TARGET_REPO = "mcp-control-plane"
+TARGET_SLUG = f"{TARGET_ORG}/{TARGET_REPO}"
+TARGET_URL = f"https://gitea.prgs.cc/{TARGET_SLUG}.git"
+
+THIRD_REPO = "Timesheet"
+THIRD_SLUG = f"{INSTALL_ORG}/{THIRD_REPO}"
+
+# tests/conftest.py installs an autouse fixture
+# (mutation_profile_fixture.install_deterministic_remote_urls) that *permanently
+# reassigns* srv._local_git_remote_url to a stub mapping remote names to fixed
+# URLs. That stub deliberately ignores the working directory, which is exactly
+# the behaviour this module must verify — so these tests would silently assert
+# against the stub rather than production code in a full-suite run. Capture the
+# genuine implementation at import time (before any fixture executes) and
+# reinstall it per test.
+_REAL_LOCAL_GIT_REMOTE_URL = srv._local_git_remote_url
+
+
+def _git(cwd: str, *args: str) -> str:
+    res = subprocess.run(
+        ["git", "-C", cwd, *args], capture_output=True, text=True, check=True
+    )
+    return res.stdout.strip()
+
+
+def _init_repo(path: Path, remote_url: str, *, remote_name: str = "origin") -> str:
+    path.mkdir(parents=True, exist_ok=True)
+    _git(str(path), "init", "-q")
+    _git(str(path), "config", "user.email", "[email protected]")
+    _git(str(path), "config", "user.name", "Test")
+    _git(str(path), "remote", "add", remote_name, remote_url)
+    # Distinct content per repo: identical seed content, author and timestamp
+    # otherwise produce byte-identical commits and therefore an identical SHA,
+    # which would make the parity-dimension assertions vacuously true.
+    (path / "README.md").write_text(f"seed {remote_url}\n")
+    _git(str(path), "add", "README.md")
+    _git(str(path), "commit", "-q", "-m", f"seed {remote_name}")
+    return os.path.realpath(str(path))
+
+
+_ROLE_OPS = {
+    "author": (
+        [
+            "gitea.read",
+            "gitea.issue.create",
+            "gitea.issue.comment",
+            "gitea.pr.create",
+            "gitea.pr.comment",
+            "gitea.branch.create",
+            "gitea.branch.push",
+            "gitea.repo.commit",
+        ],
+        ["gitea.pr.approve", "gitea.pr.merge", "gitea.pr.request_changes"],
+    ),
+    "reviewer": (
+        [
+            "gitea.read",
+            "gitea.pr.approve",
+            "gitea.pr.request_changes",
+            "gitea.pr.comment",
+            "gitea.issue.comment",
+        ],
+        ["gitea.pr.create", "gitea.branch.push", "gitea.pr.merge"],
+    ),
+    "merger": (
+        ["gitea.read", "gitea.pr.merge", "gitea.pr.comment"],
+        [
+            "gitea.pr.create",
+            "gitea.branch.push",
+            "gitea.pr.approve",
+            "gitea.pr.request_changes",
+        ],
+    ),
+    "reconciler": (
+        ["gitea.read", "gitea.pr.close", "gitea.pr.comment", "gitea.branch.delete"],
+        [
+            "gitea.pr.create",
+            "gitea.branch.push",
+            "gitea.pr.approve",
+            "gitea.pr.merge",
+            "gitea.pr.request_changes",
+        ],
+    ),
+}
+
+ROLES = tuple(_ROLE_OPS)
+
+
+def _profile(role: str, *, canonical_root: str | None = None) -> dict:
+    allowed, forbidden = _ROLE_OPS[role]
+    profile = {
+        "enabled": True,
+        "context": "prgs",
+        "role": role,
+        "username": "jcwalker3",
+        "base_url": "https://gitea.prgs.cc",
+        "auth": {"type": "env", "name": f"GITEA_TOKEN_PRGS_{role.upper()}"},
+        "allowed_operations": list(allowed),
+        "forbidden_operations": list(forbidden),
+        "execution_profile": f"prgs-{role}",
+        "allowed_repositories": [TARGET_SLUG],
+    }
+    if canonical_root is not None:
+        profile["canonical_repository_root"] = canonical_root
+    return profile
+
+
+def _config(profiles: dict) -> dict:
+    return {
+        "version": 2,
+        "rules": {"allow_runtime_switching": True},
+        "contexts": {
+            "prgs": {
+                "enabled": True,
+                "gitea": {"enabled": True, "base_url": "https://gitea.prgs.cc"},
+            }
+        },
+        "profiles": profiles,
+    }
+
+
+class _CrossRepoHarness(unittest.TestCase):
+    """Real install + target git repos, temp profiles.json, no network."""
+
+    def setUp(self):
+        self._dir = tempfile.TemporaryDirectory()
+        self.tmp = self._dir.name
+        self.config_path = os.path.join(self.tmp, "profiles.json")
+
+        # The real install checkout carries a remote literally named `prgs`;
+        # a freshly cloned target repository normally names its remote `origin`.
+        # Reproducing that asymmetry is the point: identity derivation must not
+        # depend on the remote happening to share the `remote=` argument's name.
+        self.install_root = _init_repo(
+            Path(self.tmp) / "install", INSTALL_URL, remote_name="prgs"
+        )
+        self.target_root = _init_repo(
+            Path(self.tmp) / "target", TARGET_URL, remote_name="origin"
+        )
+        self.third_root = _init_repo(
+            Path(self.tmp) / "third", f"https://gitea.prgs.cc/{THIRD_SLUG}.git"
+        )
+        self.not_a_repo = os.path.join(self.tmp, "plain-dir")
+        os.makedirs(self.not_a_repo, exist_ok=True)
+
+        session_ctx._reset_session_context_for_testing()
+        gitea_config._active_profile_override = None
+        mcp_server._IDENTITY_CACHE.clear()
+        srv._MUTATION_AUTHORITY = None
+
+        # PROJECT_ROOT is wherever the server file physically lives; pin it to a
+        # real Gitea-Tools-identified checkout so "install-derived" is
+        # deterministic regardless of the developer's layout.
+        self._project_root = patch.object(srv, "PROJECT_ROOT", self.install_root)
+        self._project_root.start()
+        # Undo the autouse deterministic-remote stub for this module only.
+        self._real_remote_url = patch.object(
+            srv, "_local_git_remote_url", _REAL_LOCAL_GIT_REMOTE_URL
+        )
+        self._real_remote_url.start()
+
+    def tearDown(self):
+        self._real_remote_url.stop()
+        self._project_root.stop()
+        session_ctx._reset_session_context_for_testing()
+        gitea_config._active_profile_override = None
+        mcp_server._IDENTITY_CACHE.clear()
+        srv._MUTATION_AUTHORITY = None
+        self._dir.cleanup()
+
+    def _write_config(self, profiles: dict) -> None:
+        with open(self.config_path, "w", encoding="utf-8") as fh:
+            fh.write(json.dumps(_config(profiles)))
+
+    def _env(self, role: str, **extra) -> dict:
+        env = {
+            "GITEA_MCP_CONFIG": self.config_path,
+            "GITEA_MCP_PROFILE": f"prgs-{role}",
+            "GITEA_TOKEN_PRGS_AUTHOR": "t",
+            "GITEA_TOKEN_PRGS_REVIEWER": "t",
+            "GITEA_TOKEN_PRGS_MERGER": "t",
+            "GITEA_TOKEN_PRGS_RECONCILER": "t",
+        }
+        env.update(extra)
+        return env
+
+    def _bind(self, role: str, canonical_root: str | None):
+        """Activate *role* with *canonical_root* and return an env patch ctx."""
+        self._write_config(
+            {f"prgs-{role}": _profile(role, canonical_root=canonical_root)}
+        )
+        return patch.dict(os.environ, self._env(role), clear=True)
+
+
+# ===========================================================================
+# 1. The central helper (single source of root resolution)
+# ===========================================================================
+class TestCanonicalLocalGitRoot(_CrossRepoHarness):
+    """_canonical_local_git_root is the one place a target root is derived."""
+
+    def test_unconfigured_namespace_uses_installation_root(self):
+        with self._bind("author", None):
+            self.assertEqual(srv._canonical_local_git_root(), self.install_root)
+
+    def test_configured_namespace_uses_target_root(self):
+        with self._bind("author", self.target_root):
+            self.assertEqual(srv._canonical_local_git_root(), self.target_root)
+
+    def test_configured_root_resolves_to_git_toplevel(self):
+        nested = os.path.join(self.target_root, "branches", "wt")
+        os.makedirs(nested, exist_ok=True)
+        with self._bind("author", nested):
+            # A subdirectory of the target repo still resolves to its toplevel.
+            self.assertEqual(srv._canonical_local_git_root(), self.target_root)
+
+    def test_invalid_root_never_silently_becomes_installation_root(self):
+        """A configured-but-broken root must not fall back to Gitea-Tools."""
+        with self._bind("author", self.not_a_repo):
+            resolved = srv._canonical_local_git_root()
+            self.assertNotEqual(resolved, self.install_root)
+            self.assertEqual(resolved, os.path.realpath(self.not_a_repo))
+
+    def test_env_override_beats_profile_binding(self):
+        self._write_config(
+            {"prgs-author": _profile("author", canonical_root=self.third_root)}
+        )
+        env = self._env("author", GITEA_CANONICAL_REPOSITORY_ROOT=self.target_root)
+        with patch.dict(os.environ, env, clear=True):
+            self.assertEqual(srv._canonical_local_git_root(), self.target_root)
+
+
+# ===========================================================================
+# 2. Repository identity — the upstream inversion
+# ===========================================================================
+class TestRepositoryIdentityDerivation(_CrossRepoHarness):
+    """_local_git_remote_url and its consumers must read the target repo."""
+
+    def test_remote_url_reads_target_not_installation(self):
+        with self._bind("author", self.target_root):
+            self.assertEqual(srv._local_git_remote_url("origin"), TARGET_URL)
+
+    def test_remote_url_unconfigured_still_reads_installation(self):
+        with self._bind("author", None):
+            # The install checkout's remote is named `prgs`, matching production.
+            self.assertEqual(srv._local_git_remote_url("prgs"), INSTALL_URL)
+
+    def test_workspace_slug_follows_canonical_root(self):
+        with self._bind("author", self.target_root):
+            self.assertEqual(srv._workspace_repository_slug("origin"), TARGET_SLUG)
+
+    def test_workspace_slug_unconfigured_is_installation(self):
+        with self._bind("author", None):
+            self.assertEqual(srv._workspace_repository_slug("prgs"), INSTALL_SLUG)
+
+    def test_every_role_derives_the_same_target_identity(self):
+        for role in ROLES:
+            with self.subTest(role=role):
+                with self._bind(role, self.target_root):
+                    self.assertEqual(
+                        srv._workspace_repository_slug("origin"), TARGET_SLUG
+                    )
+
+
+# ===========================================================================
+# 3. _resolve — omitted and explicit coordinates
+# ===========================================================================
+class TestResolveTargetCoordinates(_CrossRepoHarness):
+    """Omitted coordinates follow the binding; explicit ones may only confirm."""
+
+    def test_omitted_coordinates_resolve_to_target_repository(self):
+        for role in ROLES:
+            with self.subTest(role=role):
+                with self._bind(role, self.target_root):
+                    _host, org, repo = srv._resolve("prgs", None, None, None)
+                    self.assertEqual((org, repo), (TARGET_ORG, TARGET_REPO))
+
+    def test_omitted_coordinates_unconfigured_resolve_to_installation(self):
+        with self._bind("author", None):
+            _host, org, repo = srv._resolve("prgs", None, None, None)
+            self.assertEqual((org, repo), (INSTALL_ORG, INSTALL_REPO))
+
+    def test_explicit_matching_coordinates_confirm_the_binding(self):
+        for role in ROLES:
+            with self.subTest(role=role):
+                with self._bind(role, self.target_root):
+                    _host, org, repo = srv._resolve(
+                        "prgs", None, TARGET_ORG, TARGET_REPO
+                    )
+                    self.assertEqual((org, repo), (TARGET_ORG, TARGET_REPO))
+
+    def test_explicit_mismatched_repository_cannot_override_binding(self):
+        for role in ROLES:
+            with self.subTest(role=role):
+                with self._bind(role, self.target_root):
+                    with self.assertRaises(RuntimeError) as ctx:
+                        srv._resolve("prgs", None, TARGET_ORG, INSTALL_REPO)
+                    msg = str(ctx.exception)
+                    self.assertIn("#741", msg)
+                    self.assertIn("fail closed", msg)
+
+    def test_explicit_mismatched_organization_cannot_override_binding(self):
+        with self._bind("author", self.target_root):
+            with self.assertRaises(RuntimeError):
+                srv._resolve("prgs", None, "SomeoneElse", TARGET_REPO)
+
+    def test_gitea_tools_rooted_namespace_cannot_target_control_plane(self):
+        """Direction 1: an install-rooted namespace must not reach the target."""
+        with self._bind("author", self.install_root):
+            with self.assertRaises(RuntimeError):
+                srv._resolve("prgs", None, TARGET_ORG, TARGET_REPO)
+
+    def test_control_plane_rooted_namespace_cannot_target_gitea_tools(self):
+        """Direction 2: a target-rooted namespace must not reach Gitea-Tools."""
+        with self._bind("author", self.target_root):
+            with self.assertRaises(RuntimeError):
+                srv._resolve("prgs", None, INSTALL_ORG, INSTALL_REPO)
+
+    def test_unconfigured_namespace_keeps_existing_explicit_behaviour(self):
+        """Same-repository behaviour is unchanged (no new fail-closed path)."""
+        with self._bind("author", None):
+            _host, org, repo = srv._resolve("prgs", None, INSTALL_ORG, INSTALL_REPO)
+            self.assertEqual((org, repo), (INSTALL_ORG, INSTALL_REPO))
+
+
+# ===========================================================================
+# 4. #274 workspace guard — the two guard paths must agree
+# ===========================================================================
+class TestMutationWorkspaceGuardBinding(_CrossRepoHarness):
+    """Both guard paths must agree on which repository they protect."""
+
+    def _contexts(self, worktree: str | None = None):
+        return srv._resolve_namespace_mutation_context(worktree)
+
+    def test_mutation_context_uses_target_root(self):
+        with self._bind("author", self.target_root):
+            self.assertEqual(self._contexts()["canonical_repo_root"], self.target_root)
+
+    def test_mutation_context_unconfigured_uses_installation_root(self):
+        with self._bind("author", None):
+            self.assertEqual(self._contexts()["canonical_repo_root"], self.install_root)
+
+    def test_role_mutation_workspace_guard_agrees_with_mutation_context(self):
+        """The omitted configured_canonical_root made these two disagree."""
+        import namespace_workspace_binding as nwb
+
+        for role in ROLES:
+            with self.subTest(role=role):
+                with self._bind(role, self.target_root):
+                    configured, _src = srv._configured_canonical_root()
+                    assessment = nwb.assess_namespace_mutation_workspace(
+                        role_kind=role,
+                        worktree_path=None,
+                        worktree=None,
+                        process_project_root=srv.PROJECT_ROOT,
+                        profile_name=f"prgs-{role}",
+                        configured_canonical_root=configured,
+                    )
+                    self.assertEqual(
+                        assessment["canonical_repo_root"],
+                        self._contexts()["canonical_repo_root"],
+                    )
+                    self.assertEqual(
+                        assessment["canonical_repo_root"], self.target_root
+                    )
+
+    def test_wrong_worktree_is_rejected_against_target_root(self):
+        """A worktree belonging to the install repo is not in the target repo."""
+        import author_mutation_worktree as amw
+
+        with self._bind("author", self.target_root):
+            foreign = os.path.join(self.install_root, "branches", "wt")
+            os.makedirs(foreign, exist_ok=True)
+            membership = amw.assess_workspace_repo_membership(
+                workspace_path=foreign,
+                canonical_repo_root=self.target_root,
+            )
+            self.assertTrue(membership["block"])
+
+
+# ===========================================================================
+# 5. Canonical-root validation — missing / invalid / mismatched
+# ===========================================================================
+class TestCanonicalRootFailClosed(_CrossRepoHarness):
+    """Missing, invalid, ambiguous and mismatched roots fail closed."""
+
+    def _assess(self, value, *, expected=TARGET_SLUG, require=True):
+        return crr.assess_canonical_repository_root(
+            configured_value=value,
+            source="test",
+            expected_slug=expected,
+            process_project_root=self.install_root,
+            remote="origin",
+            require_binding=require,
+        )
+
+    def test_missing_root_fails_closed_when_binding_required(self):
+        result = self._assess(None)
+        self.assertTrue(result["block"])
+        self.assertFalse(result["configured"])
+
+    def test_missing_root_is_the_single_repo_default_when_not_required(self):
+        result = self._assess(None, expected=None, require=False)
+        self.assertFalse(result["block"])
+        self.assertEqual(result["canonical_repo_root"], self.install_root)
+
+    def test_nonexistent_root_fails_closed(self):
+        result = self._assess(os.path.join(self.tmp, "nope"))
+        self.assertTrue(result["block"])
+        self.assertIn("does not exist", " ".join(result["reasons"]))
+
+    def test_non_git_directory_fails_closed(self):
+        result = self._assess(self.not_a_repo)
+        self.assertTrue(result["block"])
+        self.assertIn("not a git repository", " ".join(result["reasons"]))
+
+    def test_mismatched_repository_identity_fails_closed(self):
+        result = self._assess(self.third_root)
+        self.assertTrue(result["block"])
+        self.assertIn("mismatch", " ".join(result["reasons"]))
+
+    def test_matching_repository_identity_is_proven(self):
+        result = self._assess(self.target_root)
+        self.assertFalse(result["block"])
+        self.assertEqual(result["resolved_slug"], TARGET_SLUG)
+        self.assertEqual(result["canonical_repo_root"], self.target_root)
+
+    def test_unresolvable_root_yields_fail_closed_reasons_not_fallback(self):
+        with self._bind("author", self.not_a_repo):
+            slug, reasons = srv._canonical_repository_slug(srv.get_profile(), "origin")
+            self.assertIsNone(slug)
+            self.assertTrue(reasons)
+
+
+# ===========================================================================
+# 6. Immutability — first bind wins, requests cannot replace the root
+# ===========================================================================
+class TestCanonicalRootImmutability(_CrossRepoHarness):
+    """No request-supplied value can establish or swap the pinned root."""
+
+    def test_first_bind_pins_target_root(self):
+        with self._bind("author", self.target_root):
+            with patch(
+                "gitea_mcp_server.api_request",
+                side_effect=lambda *a, **k: {
+                    "login": "jcwalker3",
+                    "full_name": "T",
+                    "id": 1,
+                    "email": "[email protected]",
+                },
+            ):
+                srv.gitea_whoami(remote="prgs")
+            bound = session_ctx.get_session_context()
+            self.assertEqual(bound["canonical_repository_root"], self.target_root)
+
+    def test_binding_is_first_write_wins(self):
+        with self._bind("author", self.target_root):
+            session_ctx.seed_session_context_if_unbound(
+                profile_name="prgs-author",
+                remote="prgs",
+                host="gitea.prgs.cc",
+                identity="jcwalker3",
+                org=TARGET_ORG,
+                repository=TARGET_REPO,
+                role_kind="author",
+                source="test",
+                canonical_repository_root=self.target_root,
+            )
+            # A second, contradictory seed must not replace the pin.
+            session_ctx.seed_session_context_if_unbound(
+                profile_name="prgs-author",
+                remote="prgs",
+                host="gitea.prgs.cc",
+                identity="jcwalker3",
+                org=INSTALL_ORG,
+                repository=INSTALL_REPO,
+                role_kind="author",
+                source="test-2",
+                canonical_repository_root=self.install_root,
+            )
+            bound = session_ctx.get_session_context()
+            self.assertEqual(bound["canonical_repository_root"], self.target_root)
+            self.assertEqual(bound["repository"], TARGET_REPO)
+
+    def test_request_supplied_worktree_cannot_replace_the_root(self):
+        with self._bind("author", self.target_root):
+            ctx = srv._resolve_namespace_mutation_context(self.install_root)
+            # The workspace argument may be demoted/inspected, but the canonical
+            # repository root stays the configured target.
+            self.assertEqual(ctx["canonical_repo_root"], self.target_root)
+
+    def test_request_supplied_coordinates_cannot_replace_the_root(self):
+        with self._bind("author", self.target_root):
+            with self.assertRaises(RuntimeError):
+                srv._resolve("prgs", None, INSTALL_ORG, INSTALL_REPO)
+            self.assertEqual(srv._canonical_local_git_root(), self.target_root)
+
+
+# ===========================================================================
+# 7. Parity dimensions stay separately labelled (#739 F3 preserved)
+# ===========================================================================
+class TestParityDimensionSeparation(_CrossRepoHarness):
+    """Server-implementation parity stays anchored to the install checkout."""
+
+    def test_server_dimension_is_installation_not_target(self):
+        import master_parity_gate
+
+        with self._bind("author", self.target_root):
+            head = master_parity_gate.read_git_head(srv.PROJECT_ROOT)
+            self.assertEqual(head, _git(self.install_root, "rev-parse", "HEAD"))
+            self.assertNotEqual(head, _git(self.target_root, "rev-parse", "HEAD"))
+
+    def test_target_dimension_reads_the_target_checkout(self):
+        with self._bind("author", self.target_root):
+            self.assertEqual(
+                _git(srv._canonical_local_git_root(), "rev-parse", "HEAD"),
+                _git(self.target_root, "rev-parse", "HEAD"),
+            )
+
+
+# ===========================================================================
+# 8. Configuration loaders validate the binding consistently (AC13)
+# ===========================================================================
+class TestConfigurationLoaderValidation(unittest.TestCase):
+    """Every supported loader treats canonical_repository_root identically."""
+
+    def setUp(self):
+        self._dir = tempfile.TemporaryDirectory()
+        self.tmp = self._dir.name
+
+    def tearDown(self):
+        self._dir.cleanup()
+
+    def _write(self, data: dict) -> str:
+        path = os.path.join(self.tmp, "profiles.json")
+        with open(path, "w", encoding="utf-8") as fh:
+            fh.write(json.dumps(data))
+        return path
+
+    # --- v1 ---------------------------------------------------------------
+    def _v1(self, root):
+        return {
+            "version": 1,
+            "profiles": {
+                "prgs-author": {
+                    "base_url": "https://gitea.prgs.cc",
+                    "auth": {"type": "env", "name": "GITEA_TOKEN"},
+                    "canonical_repository_root": root,
+                }
+            },
+        }
+
+    def test_v1_rejects_relative_canonical_root(self):
+        path = self._write(self._v1("relative/path"))
+        with self.assertRaises(gitea_config.ConfigError) as ctx:
+            gitea_config.load_config(path)
+        self.assertIn("absolute", str(ctx.exception))
+
+    def test_v1_rejects_blank_canonical_root(self):
+        path = self._write(self._v1("   "))
+        with self.assertRaises(gitea_config.ConfigError):
+            gitea_config.load_config(path)
+
+    def test_v1_accepts_absolute_canonical_root(self):
+        path = self._write(self._v1("/abs/target"))
+        loaded = gitea_config.load_config(path)
+        self.assertEqual(
+            loaded["profiles"]["prgs-author"]["canonical_repository_root"],
+            "/abs/target",
+        )
+
+    def test_v1_without_the_field_is_unchanged(self):
+        data = self._v1("/abs/target")
+        del data["profiles"]["prgs-author"]["canonical_repository_root"]
+        loaded = gitea_config.load_config(self._write(data))
+        self.assertNotIn("canonical_repository_root", loaded["profiles"]["prgs-author"])
+
+    # --- v2 environments --------------------------------------------------
+    def _v2_env(self, root):
+        ident = {
+            "auth": {"type": "env", "name": "GITEA_TOKEN"},
+            "base_url": "https://gitea.prgs.cc",
+            "username": "jcwalker3",
+            "allowed_operations": ["gitea.read"],
+        }
+        if root is not None:
+            ident["canonical_repository_root"] = root
+        return {
+            "version": 2,
+            "environments": {
+                "prgs": {"services": {"gitea": {"identities": {"author": ident}}}}
+            },
+        }
+
+    def test_v2_environments_propagates_canonical_root(self):
+        """Regression: the field was silently dropped during flattening."""
+        loaded = gitea_config.load_config(self._write(self._v2_env("/abs/target")))
+        profile = loaded["profiles"]["prgs.gitea.author"]
+        self.assertEqual(profile["canonical_repository_root"], "/abs/target")
+
+    def test_v2_environments_rejects_relative_canonical_root(self):
+        with self.assertRaises(gitea_config.ConfigError) as ctx:
+            gitea_config.load_config(self._write(self._v2_env("relative/path")))
+        self.assertIn("absolute", str(ctx.exception))
+
+    def test_v2_environments_without_the_field_is_unchanged(self):
+        loaded = gitea_config.load_config(self._write(self._v2_env(None)))
+        self.assertNotIn(
+            "canonical_repository_root", loaded["profiles"]["prgs.gitea.author"]
+        )
+
+    # --- v2 contexts (already validated; guard against regression) ---------
+    def test_v2_contexts_still_rejects_relative_canonical_root(self):
+        data = {
+            "version": 2,
+            "contexts": {
+                "prgs": {
+                    "enabled": True,
+                    "gitea": {"enabled": True, "base_url": "https://gitea.prgs.cc"},
+                }
+            },
+            "profiles": {
+                "prgs-author": {
+                    "enabled": True,
+                    "context": "prgs",
+                    "username": "jcwalker3",
+                    "auth": {"type": "env", "name": "GITEA_TOKEN"},
+                    "allowed_operations": ["gitea.read"],
+                    "canonical_repository_root": "relative/path",
+                }
+            },
+        }
+        with self.assertRaises(gitea_config.ConfigError):
+            gitea_config.load_config(self._write(data))
+
+
+# ===========================================================================
+# 9. Role-by-operation matrix
+# ===========================================================================
+class TestRoleOperationMatrix(_CrossRepoHarness):
+    """Each role, each cross-repository condition, one assertion per cell."""
+
+    def test_correct_target_resolves_for_every_role(self):
+        for role in ROLES:
+            with self.subTest(role=role, case="correct-target"):
+                with self._bind(role, self.target_root):
+                    _h, org, repo = srv._resolve("prgs", None, None, None)
+                    self.assertEqual((org, repo), (TARGET_ORG, TARGET_REPO))
+
+    def test_wrong_repository_is_rejected_for_every_role(self):
+        for role in ROLES:
+            with self.subTest(role=role, case="wrong-repo"):
+                with self._bind(role, self.target_root):
+                    with self.assertRaises(RuntimeError):
+                        srv._resolve("prgs", None, INSTALL_ORG, INSTALL_REPO)
+
+    def test_explicit_matching_coordinates_pass_for_every_role(self):
+        for role in ROLES:
+            with self.subTest(role=role, case="explicit-match"):
+                with self._bind(role, self.target_root):
+                    _h, org, repo = srv._resolve("prgs", None, TARGET_ORG, TARGET_REPO)
+                    self.assertEqual((org, repo), (TARGET_ORG, TARGET_REPO))
+
+    def test_explicit_mismatch_fails_closed_for_every_role(self):
+        for role in ROLES:
+            with self.subTest(role=role, case="explicit-mismatch"):
+                with self._bind(role, self.target_root):
+                    with self.assertRaises(RuntimeError):
+                        srv._resolve("prgs", None, INSTALL_ORG, THIRD_REPO)
+
+    def test_missing_canonical_root_preserves_single_repo_default(self):
+        for role in ROLES:
+            with self.subTest(role=role, case="missing-root"):
+                with self._bind(role, None):
+                    self.assertEqual(srv._canonical_local_git_root(), self.install_root)
+
+    def test_invalid_canonical_root_never_becomes_install_root(self):
+        for role in ROLES:
+            with self.subTest(role=role, case="invalid-root"):
+                with self._bind(role, self.not_a_repo):
+                    self.assertNotEqual(
+                        srv._canonical_local_git_root(), self.install_root
+                    )
+
+    def test_wrong_worktree_rejected_for_every_role(self):
+        import author_mutation_worktree as amw
+
+        foreign = os.path.join(self.install_root, "branches", "foreign")
+        os.makedirs(foreign, exist_ok=True)
+        for role in ROLES:
+            with self.subTest(role=role, case="wrong-worktree"):
+                with self._bind(role, self.target_root):
+                    membership = amw.assess_workspace_repo_membership(
+                        workspace_path=foreign,
+                        canonical_repo_root=srv._canonical_local_git_root(),
+                    )
+                    self.assertTrue(membership["block"])
+
+    def test_request_override_attempt_rejected_for_every_role(self):
+        for role in ROLES:
+            with self.subTest(role=role, case="request-override"):
+                with self._bind(role, self.target_root):
+                    with self.assertRaises(RuntimeError):
+                        srv._resolve("prgs", None, "Attacker", "evil-repo")
+                    self.assertEqual(srv._canonical_local_git_root(), self.target_root)
+
+
+if __name__ == "__main__":
+    unittest.main()