feat(mcp): enforce strict cross-project mutation boundaries (Closes #707)

gitea_mcp_server.py

@@ -3325,10 +3325,16 @@ def _effective_remote(remote: str) -> str:
     return remote
 
 
-def _resolve(remote: str, host: str | None, org: str | None, repo: str | None):
+def _resolve(
+    remote: str,
+    host: str | None,
+    org: str | None,
+    repo: str | None,
+    for_mutation: bool = False,
+):
     """Resolve remote + overrides to (host, org, repo).
 
-    #714 / #530: when the caller omits org and/or repo, prefer the
+    #714 / #530 / #707: when the caller omits org and/or repo, prefer the
     workspace-aligned git remote over ``REMOTES`` defaults (e.g. bare
     ``remote=prgs`` must not force ``Timesheet`` when the checkout is
     ``Gitea-Tools``). Explicit caller org/repo always win and are validated
@@ -3414,6 +3420,7 @@ def _resolve(remote: str, host: str | None, org: str | None, repo: str | None):
         # Workspace-filled sides are intentional alignment for #530.
         org_explicit=org_explicit or filled_org,
         repo_explicit=repo_explicit or filled_repo,
+        for_mutation=for_mutation,
     )
     return (resolved_host, resolved_org, resolved_repo)
 
@@ -3475,8 +3482,9 @@ def _enforce_remote_repo_guard(
     *,
     org_explicit: bool,
     repo_explicit: bool,
+    for_mutation: bool = False,
 ) -> None:
-    """Fail closed on a remote/repo mismatch vs. the local git remote (#530).
+    """Fail closed on a remote/repo mismatch vs. the local git remote (#530/#707).
 
     Best-effort: bypassed under pytest unless ``GITEA_FORCE_REMOTE_REPO_CHECK`` is
     set, so the unit suite (which calls tools with bare remotes against mocked APIs)
@@ -3488,6 +3496,12 @@ def _enforce_remote_repo_guard(
     ):
         return
     local_remote_url = _local_git_remote_url(remote)
+    primary_org = None
+    primary_repo = None
+    ctx = session_ctx.get_session_context()
+    if ctx:
+        primary_org = ctx.get("org")
+        primary_repo = ctx.get("repository")
     assessment = remote_repo_guard.assess_remote_repo_match(
         remote=remote,
         resolved_org=resolved_org,
@@ -3495,6 +3509,9 @@ def _enforce_remote_repo_guard(
         local_remote_url=local_remote_url,
         org_explicit=org_explicit,
         repo_explicit=repo_explicit,
+        for_mutation=for_mutation,
+        primary_org=primary_org,
+        primary_repo=primary_repo,
     )
     if assessment["block"]:
         raise RuntimeError(remote_repo_guard.format_remote_repo_guard_error(assessment))
@@ -4063,7 +4080,7 @@ def gitea_lock_issue(
     resolved_worktree = issue_lock_worktree.resolve_author_worktree_path(
         worktree_path, _canonical_local_git_root()
     )
-    h, o, r = _resolve(remote, host, org, repo)
+    h, o, r = _resolve(remote, host, org, repo, for_mutation=True)
     existing_issue_lock = _load_existing_issue_lock(
         remote=remote, org=o, repo=r, issue_number=issue_number
     )
@@ -5239,7 +5256,7 @@ def gitea_create_pr(
             org=org,
             repo=repo,
         )
-    h, o, r = _resolve(remote, host, org, repo)
+    h, o, r = _resolve(remote, host, org, repo, for_mutation=True)
 
     # ── Issue Lock Validation (Issue #194 / #196 / #443) ──
     lock_data = _resolve_issue_lock_for_pr(remote=remote, org=o, repo=r, head=head)
@@ -9560,7 +9577,7 @@ def gitea_edit_pr(
                 required_permission="gitea.pr.close",
             )
 
-    h, o, r = _resolve(remote, host, org, repo)
+    h, o, r = _resolve(remote, host, org, repo, for_mutation=True)
     auth = _auth(h)
     url = f"{repo_api_url(h, o, r)}/pulls/{pr_number}"
 
@@ -9844,7 +9861,7 @@ def gitea_commit_files(
     verify_preflight_purity(remote=remote, worktree_path=worktree_path, task="commit_files", org=org, repo=repo)
     processed_files, source_proofs = _prepare_commit_payload_files(files)
 
-    h, o, r = _resolve(remote, host, org, repo)
+    h, o, r = _resolve(remote, host, org, repo, for_mutation=True)
     auth = _auth(h)
     url = f"{repo_api_url(h, o, r)}/contents"
 
@@ -9980,7 +9997,7 @@ def gitea_publish_unpublished_issue_branch(
         repo=repo,
     )
 
-    h, o, r = _resolve(remote, host, org, repo)
+    h, o, r = _resolve(remote, host, org, repo, for_mutation=True)
     git_remote = (git_remote_name or remote or "").strip()
 
     existing_lock = issue_lock_store.load_issue_lock(
@@ -10183,7 +10200,7 @@ def gitea_bootstrap_author_issue_worktree(
         repo=repo,
     )
 
-    h, o, r = _resolve(remote, host, org, repo)
+    h, o, r = _resolve(remote, host, org, repo, for_mutation=True)
     canonical_root = _canonical_local_git_root()
 
     import author_issue_bootstrap
@@ -12131,7 +12148,7 @@ def gitea_reconcile_merged_cleanups(
                 "blocker_kind": "invalid_pr_number",
             }
 
-    h, o, r = _resolve(remote, host, org, repo)
+    h, o, r = _resolve(remote, host, org, repo, for_mutation=True)
     auth = _auth(h)
     base = repo_api_url(h, o, r)
 
@@ -12521,7 +12538,7 @@ def gitea_assess_already_landed_reconciliation(
             "permission_report": _permission_block_report("gitea.read"),
         }
 
-    h, o, r = _resolve(remote, host, org, repo)
+    h, o, r = _resolve(remote, host, org, repo, for_mutation=True)
     auth = _auth(h)
     pr = api_request("GET", f"{repo_api_url(h, o, r)}/pulls/{pr_number}", auth)
 

remote_repo_guard.py

@@ -54,20 +54,62 @@ def assess_remote_repo_match(
     local_remote_url: str | None,
     org_explicit: bool,
     repo_explicit: bool,
+    for_mutation: bool = False,
+    primary_org: str | None = None,
+    primary_repo: str | None = None,
 ) -> dict:
     """Fail closed when the resolved org/repo disagrees with the local git remote.
 
-    The guard is intentionally conservative:
+    The guard enforces two protection levels:
 
-    * When the caller passed both ``org`` and ``repo`` explicitly, their intent is
-      authoritative and the guard never blocks.
-    * When the local git remote URL is unavailable (``None``/empty), corroboration
-      is impossible, so the guard does not block (best-effort only).
-    * Otherwise, the resolved ``org/repo`` slug must appear in the local remote URL
-      (case-insensitive); if it does not, the guard blocks.
+    1. Cross-Project Mutation Boundary (#707):
+       When ``for_mutation`` is True (codebase mutation operation: branch, commit, PR,
+       merge, branch deletion), the target repository (``resolved_org/resolved_repo``)
+       MUST match the primary authorized project context (``primary_org/primary_repo``
+       or parsed from ``local_remote_url``). Any attempt to mutate a different project
+       fails closed, even if explicit org/repo were passed. Metadata operations (such
+       as creating issues or commenting on issues) across projects remain allowed.
+
+    2. Workspace Mismatch Guard (#530):
+       When ``for_mutation`` is False (or targets match), bare remotes must resolve
+       to an org/repo slug present in the local git remote URL. When explicit org/repo
+       are supplied for non-mutation operations, the caller's intent is authoritative.
     """
     reasons: list[str] = []
 
+    eff_primary_org = primary_org
+    eff_primary_repo = primary_repo
+    if not eff_primary_org or not eff_primary_repo:
+        parsed_primary = parse_org_repo_from_remote_url(local_remote_url)
+        if parsed_primary:
+            eff_primary_org = eff_primary_org or parsed_primary[0]
+            eff_primary_repo = eff_primary_repo or parsed_primary[1]
+
+    # #707: Enforce cross-project codebase mutation boundary if for_mutation is True
+    if for_mutation and eff_primary_org and eff_primary_repo:
+        if (
+            resolved_org.lower() != eff_primary_org.lower()
+            or resolved_repo.lower() != eff_primary_repo.lower()
+        ):
+            reasons.append(
+                f"Cross-project mutation guard (#707): Attempted codebase mutation targeting "
+                f"'{resolved_org}/{resolved_repo}' outside of primary authorized project "
+                f"context '{eff_primary_org}/{eff_primary_repo}'"
+            )
+            return {
+                "proven": False,
+                "block": True,
+                "cross_project_mutation_block": True,
+                "reasons": reasons,
+                "remote": remote,
+                "resolved_org": resolved_org,
+                "resolved_repo": resolved_repo,
+                "primary_org": eff_primary_org,
+                "primary_repo": eff_primary_repo,
+                "local_remote_url": local_remote_url,
+                "remediation": f"Cross-project codebase work is forbidden. Create an issue in the target repository ('{resolved_org}/{resolved_repo}') instead.",
+            }
+
     if org_explicit and repo_explicit:
         return _assessment(True, reasons, remote, resolved_org, resolved_repo, local_remote_url)
 
@@ -88,6 +130,16 @@ def assess_remote_repo_match(
 
 def format_remote_repo_guard_error(assessment: dict) -> str:
     """Single RuntimeError message for the MCP resolver gate."""
+    if assessment.get("cross_project_mutation_block"):
+        resolved = f"{assessment.get('resolved_org')}/{assessment.get('resolved_repo')}"
+        primary = f"{assessment.get('primary_org')}/{assessment.get('primary_repo')}"
+        return (
+            f"Cross-project mutation guard (#707): Attempted codebase mutation targeting '{resolved}' "
+            f"outside of primary authorized project context '{primary}'. "
+            f"Cross-project codebase work (creating branches, committing files, creating PRs) is forbidden; "
+            f"create an issue in the target repository ('{resolved}') instead."
+        )
+
     reasons = "; ".join(
         assessment.get("reasons") or ["remote/repo resolution mismatch"]
     )
@@ -120,3 +172,4 @@ def _assessment(
         "local_remote_url": local_remote_url,
         "remediation": REMEDIATION,
     }
+

tests/test_cross_project_mutation_boundary.py

@@ -0,0 +1,94 @@
+import os
+import sys
+import unittest
+from unittest import mock
+
+import remote_repo_guard
+import gitea_mcp_server as server
+from session_context_binding import _reset_session_context_for_testing, bind_session_context
+
+
+LOCAL_GITEA_TOOLS_URL = "https://gitea.prgs.cc/Scaled-Tech-Consulting/Gitea-Tools.git"
+
+
+class TestCrossProjectMutationBoundary(unittest.TestCase):
+    def setUp(self):
+        os.environ["PYTEST_CURRENT_TEST"] = "test"
+        _reset_session_context_for_testing()
+
+    def tearDown(self):
+        _reset_session_context_for_testing()
+        os.environ.pop("PYTEST_CURRENT_TEST", None)
+
+    def test_cross_project_codebase_mutation_blocked(self):
+        """Codebase mutations targeting another project must fail closed (#707)."""
+        assessment = remote_repo_guard.assess_remote_repo_match(
+            remote="prgs",
+            resolved_org="Other-Org",
+            resolved_repo="Other-Repo",
+            local_remote_url=LOCAL_GITEA_TOOLS_URL,
+            org_explicit=True,
+            repo_explicit=True,
+            for_mutation=True,
+        )
+        self.assertTrue(assessment["block"])
+        self.assertTrue(assessment.get("cross_project_mutation_block"))
+        self.assertEqual(assessment["primary_org"], "Scaled-Tech-Consulting")
+        self.assertEqual(assessment["primary_repo"], "Gitea-Tools")
+
+        err_msg = remote_repo_guard.format_remote_repo_guard_error(assessment)
+        self.assertIn("Cross-project mutation guard (#707)", err_msg)
+        self.assertIn("Attempted codebase mutation targeting 'Other-Org/Other-Repo'", err_msg)
+        self.assertIn("outside of primary authorized project context 'Scaled-Tech-Consulting/Gitea-Tools'", err_msg)
+        self.assertIn("create an issue in the target repository ('Other-Org/Other-Repo') instead", err_msg)
+
+    def test_same_project_codebase_mutation_allowed(self):
+        """Codebase mutations targeting the primary project context are allowed."""
+        assessment = remote_repo_guard.assess_remote_repo_match(
+            remote="prgs",
+            resolved_org="Scaled-Tech-Consulting",
+            resolved_repo="Gitea-Tools",
+            local_remote_url=LOCAL_GITEA_TOOLS_URL,
+            org_explicit=True,
+            repo_explicit=True,
+            for_mutation=True,
+        )
+        self.assertFalse(assessment["block"])
+        self.assertFalse(assessment.get("cross_project_mutation_block", False))
+
+    def test_cross_project_metadata_operation_allowed(self):
+        """Metadata operations (issue creation, comments) across project boundaries are allowed."""
+        assessment = remote_repo_guard.assess_remote_repo_match(
+            remote="prgs",
+            resolved_org="Other-Org",
+            resolved_repo="Other-Repo",
+            local_remote_url=LOCAL_GITEA_TOOLS_URL,
+            org_explicit=True,
+            repo_explicit=True,
+            for_mutation=False,
+        )
+        self.assertTrue(assessment["proven"])
+        self.assertFalse(assessment["block"])
+
+    @mock.patch.dict(os.environ, {"GITEA_FORCE_REMOTE_REPO_CHECK": "1"})
+    @mock.patch("gitea_mcp_server._local_git_remote_url", return_value=LOCAL_GITEA_TOOLS_URL)
+    def test_mcp_server_resolve_cross_project_mutation_fails_closed(self, mock_remote):
+        """_resolve with for_mutation=True blocks cross-project targets."""
+        with self.assertRaises(RuntimeError) as ctx:
+            server._resolve("prgs", None, "Other-Org", "Other-Repo", for_mutation=True)
+        
+        err = str(ctx.exception)
+        self.assertIn("Cross-project mutation guard (#707)", err)
+        self.assertIn("create an issue in the target repository", err)
+
+    @mock.patch.dict(os.environ, {"GITEA_FORCE_REMOTE_REPO_CHECK": "1"})
+    @mock.patch("gitea_mcp_server._local_git_remote_url", return_value=LOCAL_GITEA_TOOLS_URL)
+    def test_mcp_server_resolve_cross_project_metadata_succeeds(self, mock_remote):
+        """_resolve with for_mutation=False allows explicit cross-project target."""
+        host, org, repo = server._resolve("prgs", None, "Other-Org", "Other-Repo", for_mutation=False)
+        self.assertEqual(org, "Other-Org")
+        self.assertEqual(repo, "Other-Repo")
+
+
+if __name__ == "__main__":
+    unittest.main()