fix: degrade review gate on quota exhaustion (#55)

Co-authored-by: Codex <noreply@openai.com>

Author: Pigbibi

scripts/codex_audit_service.py

@@ -690,7 +690,7 @@ def _job_dedupe_key(payload: dict[str, Any]) -> str:
 
 
 def _classify_codex_exec_failure(text: str) -> str:
-    if any(word in text for word in ("quota", "rate limit", "too many active", "budget")):
+    if any(word in text for word in ("quota", "rate limit", "too many active", "budget", "usage limit")):
         return "quota_or_capacity_failure"
     return "unknown_failure"
 

scripts/run_codex_pr_review.py

@@ -491,7 +491,9 @@ def run_codex_service_review(prompt: str, timeout_minutes: int, complexity: str
             return output.strip()
         if status == "failed":
             error = str(job_payload.get("error") or "unknown failure")
-            raise ReviewError(f"Codex service job failed: {error[:600]}")
+            failure_category = str(job_payload.get("failure_category") or "").strip()
+            category_suffix = f" [{failure_category}]" if failure_category else ""
+            raise ReviewError(f"Codex service job failed{category_suffix}: {error[:600]}")
         if status not in {"queued", "running"}:
             raise ReviewError(f"Unexpected Codex service status: {status!r}")
 
@@ -509,6 +511,11 @@ def _review_backend_is_unconfigured(exc: ReviewError) -> bool:
     return message == NO_REVIEW_BACKEND_CONFIGURED or "oidc repository is not allowed" in normalized
 
 
+def _review_capacity_is_unavailable(exc: ReviewError) -> bool:
+    message = str(exc).lower()
+    return "[quota_or_capacity_failure]" in message or "usage limit" in message
+
+
 def _api_fallback_enabled() -> bool:
     return parse_bool(env_value("CODEX_PR_REVIEW_API_FALLBACK_ENABLED", "true"))
 
@@ -1260,6 +1267,16 @@ def main() -> int:
             changed_line_count=len(diff.splitlines()),
         )
     except ReviewError as exc:
+        if _review_capacity_is_unavailable(exc):
+            print(f"::warning::Codex review unavailable due to quota or capacity: {exc}")
+            warning_body = (
+                "<!-- codex-pr-review -->\n"
+                "## 🤖 Codex PR Review\n\n"
+                "⚠️ **Review unavailable**: Codex review quota or capacity is unavailable. "
+                "No direct paid API fallback was used; required CI checks remain the merge gate.\n"
+            )
+            upsert_pr_comment(token, repo, pr_number, warning_body)
+            return 0
         print(f"::error::Codex review failed: {exc}", file=sys.stderr)
         warning_body = (
             "<!-- codex-pr-review -->\n"

tests/test_codex_audit_service_complexity.py

@@ -117,6 +117,12 @@ def test_task_requires_async_review_and_execute(self) -> None:
         with self.assertRaisesRegex(ValueError, "Unsupported task='analyze'"):
             _service.resolve_adapter("analyze", "")
 
+    def test_codex_usage_limit_is_classified_as_capacity_failure(self) -> None:
+        self.assertEqual(
+            _service._classify_codex_exec_failure("You have reached your Codex usage limits for code reviews."),
+            "quota_or_capacity_failure",
+        )
+
     def test_direct_api_model_for_complexity_reads_provider_specific_env(self) -> None:
         with mock.patch.dict(
             "os.environ",

tests/test_run_codex_pr_review.py

@@ -358,6 +358,33 @@ def test_main_blocks_high_risk_on_review_infra_error(self) -> None:
         backend.assert_called_once()
         self.assertIn("Merge blocked", comment.call_args.args[3])
 
+    def test_main_allows_required_ci_to_gate_when_review_quota_is_unavailable(self) -> None:
+        with tempfile.TemporaryDirectory() as tmpdir:
+            event_path = self._write_event(tmpdir, ["src/app.py"])
+            env = {
+                "GH_TOKEN": "token",
+                "GITHUB_REPOSITORY": "org/repo",
+                "GITHUB_EVENT_PATH": event_path,
+                "GITHUB_EVENT_NAME": "pull_request",
+            }
+            with (
+                patch.dict(os.environ, env, clear=True),
+                patch("scripts.run_codex_pr_review.fetch_pr_files", return_value=[{"filename": "src/app.py"}]),
+                patch("scripts.run_codex_pr_review.fetch_pr_diff", return_value="diff --git a/src/app.py b/src/app.py"),
+                patch("scripts.run_codex_pr_review.load_policy", return_value=run_codex_pr_review._default_policy()),
+                patch("scripts.run_codex_pr_review.find_existing_review_comment", return_value=(None, "")),
+                patch(
+                    "scripts.run_codex_pr_review.run_codex_review_with_fallback",
+                    side_effect=ReviewError("Codex service job failed [quota_or_capacity_failure]: usage limits reached"),
+                ),
+                patch("scripts.run_codex_pr_review.upsert_pr_comment") as comment,
+            ):
+                self.assertEqual(run_codex_pr_review.main(), 0)
+
+        comment.assert_called_once()
+        self.assertIn("Review unavailable", comment.call_args.args[3])
+        self.assertNotIn("Merge blocked", comment.call_args.args[3])
+
     def test_main_skips_low_risk_docs_before_calling_review_backend(self) -> None:
         with tempfile.TemporaryDirectory() as tmpdir:
             event_path = self._write_event(tmpdir, ["docs/guide.md", "tests/test_x.py"])