Add explicit close_pr capability resolution and gated PR close path (Issue #216)

PR closure had no first-class capability: agents could close PRs through
gitea_edit_pr(state=closed) with no close-specific capability proof, and
gitea_resolve_task_capability(close_pr) failed as unknown, leaving the
broad edit path as an untracked close fallback.

Add close_pr to the resolver TASK_MAP (gitea.pr.close, author-side) and
gate gitea_edit_pr(state=closed) on the same operation: without it the
close fails closed before any auth or API call, with reasons and a
structured permission_report; with it the close proceeds and is audited
as a distinct close_pr action carrying the required capability. Reject
invalid state values outright so case variants cannot bypass the gate.
Generalize the profile gate helper (_profile_operation_gate) and document
the PR comment / PR edit / PR close capability split.

Co-Authored-By: Claude Fable 5 <[email protected]>

mcp_server.py

@@ -841,7 +841,7 @@ def gitea_get_pr_review_feedback(
         'feedback_not_attempted' True, 'reasons', and 'permission_report' —
         deliberately distinct from a successful "no reviews yet" result.
     """
-    reasons = _issue_comment_gate("gitea.read")
+    reasons = _profile_operation_gate("gitea.read")
     if reasons:
         return {
             "success": False,
@@ -1073,11 +1073,20 @@ def gitea_edit_pr(
 ) -> dict:
     """Edit an existing pull request on a Gitea repository.
 
+    Closing a PR (``state='closed'``) is a distinct capability from other
+    edits (#216): it requires the ``gitea.pr.close`` operation (resolver
+    task ``close_pr``), fails closed with a structured permission report
+    when the active profile lacks it, and is audited as a distinct
+    ``close_pr`` action. Title/body/base edits and reopening stay on the
+    ordinary edit path, so the edit tool can never be used as an untracked
+    close fallback.
+
     Args:
         pr_number: The pull request index/number (required).
         title: New PR title.
         body: New PR description.
-        state: New state — 'open' or 'closed'.
+        state: New state — 'open' or 'closed'. 'closed' requires the
+            ``gitea.pr.close`` capability.
         base: Target branch name.
         remote: Known instance — 'dadeschools' or 'prgs'.
         host: Override the Gitea host.
@@ -1085,7 +1094,10 @@ def gitea_edit_pr(
         repo: Override the repository name.
 
     Returns:
-        dict with success status and details of the edited PR.
+        dict with success status and details of the edited PR. A close
+        attempt without ``gitea.pr.close`` returns 'success'/'performed'
+        False with 'reasons' and a structured 'permission_report' and makes
+        no API call.
     """
     # Validate inputs BEFORE any auth/profile resolution or API setup: a
     # no-fields call is a pure validation error and must not depend on
@@ -1096,6 +1108,9 @@ def gitea_edit_pr(
     if body is not None:
         payload["body"] = body
     if state is not None:
+        if state not in ("open", "closed"):
+            raise ValueError(
+                f"Invalid state {state!r}: must be 'open' or 'closed' (fail closed).")
         payload["state"] = state
     if base is not None:
         payload["base"] = base
@@ -1103,12 +1118,33 @@ def gitea_edit_pr(
     if not payload:
         raise ValueError("At least one field to edit (title, body, state, base) must be provided.")
 
+    # PR closure is a first-class capability, distinct from retitling or
+    # rebasing edits (#216). Gate BEFORE auth/API setup so a blocked close
+    # never touches the network.
+    closing = payload.get("state") == "closed"
+    if closing:
+        gate_reasons = _profile_operation_gate("gitea.pr.close")
+        if gate_reasons:
+            return {
+                "success": False,
+                "performed": False,
+                "pr_number": pr_number,
+                "requested_state": "closed",
+                "required_permission": "gitea.pr.close",
+                "reasons": gate_reasons,
+                "permission_report": _permission_block_report("gitea.pr.close"),
+            }
+
     h, o, r = _resolve(remote, host, org, repo)
     auth = _auth(h)
     url = f"{repo_api_url(h, o, r)}/pulls/{pr_number}"
 
-    with _audited("edit_pr", host=h, remote=remote, org=o, repo=r,
-                  pr_number=pr_number, request_metadata={"fields": sorted(payload)}):
+    request_metadata = {"fields": sorted(payload)}
+    if closing:
+        request_metadata["required_permission"] = "gitea.pr.close"
+    with _audited("close_pr" if closing else "edit_pr",
+                  host=h, remote=remote, org=o, repo=r,
+                  pr_number=pr_number, request_metadata=request_metadata):
         data = api_request("PATCH", url, auth, payload)
 
     cleanup_status = None
@@ -1869,13 +1905,14 @@ def _permission_block_report(required_operation: str,
     return report
 
 
-def _issue_comment_gate(op: str) -> list[str]:
-    """Profile permission check for issue-comment tools (#126).
+def _profile_operation_gate(op: str) -> list[str]:
+    """Profile permission check for a single gated operation (#126, #216).
 
     Issue discussion comments are gated separately from the gitea.pr.*
     review/merge family: listing requires ``gitea.read``, creating requires
-    ``gitea.issue.comment``. Returns a list of block reasons (empty = allowed);
-    an unreadable profile fails closed.
+    ``gitea.issue.comment``. Closing a PR requires the distinct
+    ``gitea.pr.close`` (#216). Returns a list of block reasons (empty =
+    allowed); an unreadable profile fails closed.
     """
     try:
         profile = get_profile()
@@ -1927,7 +1964,7 @@ def gitea_list_issue_comments(
         'success' False, 'reasons', and a structured 'permission_report'
         (#142) with no API call made.
     """
-    reasons = _issue_comment_gate("gitea.read")
+    reasons = _profile_operation_gate("gitea.read")
     if reasons:
         return {"success": False, "issue_number": issue_number,
                 "reasons": reasons,
@@ -1989,7 +2026,7 @@ def gitea_create_issue_comment(
         (permission blocks also carry a structured 'permission_report',
         #142).
     """
-    gate_reasons = _issue_comment_gate("gitea.issue.comment")
+    gate_reasons = _profile_operation_gate("gitea.issue.comment")
     reasons = list(gate_reasons)
     if not (body or "").strip():
         reasons.append("comment body must be a non-empty string")
@@ -3353,6 +3390,14 @@ def gitea_resolve_task_capability(
             "permission": "gitea.pr.comment",
             "role": "author",
         },
+        # PR closure is a first-class capability (#216): distinct from
+        # comment_pr (gitea.pr.comment) and from ordinary PR edits, which
+        # need no dedicated capability. gitea_edit_pr(state='closed') is
+        # gated on the same operation, so no edit-path fallback exists.
+        "close_pr": {
+            "permission": "gitea.pr.close",
+            "role": "author",
+        },
         "address_pr_change_requests": {
             "permission": "gitea.branch.push",
             "role": "author",