⚡ Bolt: [performance improvement] Parallelize GitHub API calls in agent router

.jules/bolt.md

@@ -51,3 +51,7 @@
 ## 2026-08-29 - [대용량 텍스트 스캔 시 정규표현식 대신 네이티브 메서드 활용]
 **Learning:** `scripts/ci/opencode_review_normalize_output.py`의 라벨 스캐닝 루프에서 긴 LLM 리뷰 텍스트를 대상으로 `pattern.finditer()`를 호출하는 패턴이 있었습니다. 마이크로 벤치마크 결과, 단순 문자열 매칭에서는 네이티브 `str.find()`와 `while` 루프를 조합하는 것이 정규표현식 실행 오버헤드 없이 훨씬 빠르다는 것을 확인했습니다.
 **Action:** 내부 탐색 루프에서 정확히 일치하는 리터럴 문자열(라벨 접두사 등)을 검색할 때는 `re.compile(re.escape(string)).finditer()` 대신 고도로 최적화된 Python 네이티브 `text.find(candidate, index)` 메서드를 사용하십시오. 단, 무한 루프를 방지하기 위해 루프의 모든 분기에서 인덱스가 올바르게 진행되도록 보장해야 합니다.
+
+## 2026-09-12 - Avoid N+1 API blocking in agent router
+**Learning:** The `dispatched_agents` function in `scripts/ci/agent_mention_router.py` was fetching ledger artifacts from the GitHub API synchronously for each agent. This N+1 network/API bottleneck stalled execution when multiple agents were requested.
+**Action:** Use `concurrent.futures.ThreadPoolExecutor` bounded by a small `max_workers` to concurrently fetch ledger artifacts for multiple agents, avoiding sequential API delays while keeping the fast serial path for single-item inputs. Also, explicitly instantiate the executor and shut it down in a `finally` block to avoid hang issues.

scripts/ci/agent_mention_router.py

@@ -4,6 +4,7 @@
 from __future__ import annotations
 
 import argparse
+import concurrent.futures
 import hashlib
 import json
 import os
@@ -383,24 +384,46 @@ def dispatched_agents(
     artifact_cache = (
         ledger_artifact_cache if ledger_artifact_cache is not None else {}
     )
+
+    def _fetch_agent(agent: str) -> None:
+        """Fetch and cache exact-name artifacts for a single agent."""
+        artifact_name = agent_ledger_artifact_name(request, agent)
+        response = dispatch_client.request(
+            [
+                LEDGER_ARTIFACTS_ENDPOINT,
+                "-X",
+                "GET",
+                "-f",
+                f"name={artifact_name}",
+                "-f",
+                "per_page=100",
+            ]
+        )
+        artifact_cache[artifact_name] = bool(
+            _artifact_records(response, expected_name=artifact_name)
+        )
+
+    agents_to_fetch = [
+        agent
+        for agent in candidates
+        if agent_ledger_artifact_name(request, agent) not in artifact_cache
+    ]
+
+    if len(agents_to_fetch) <= 1:
+        for agent in agents_to_fetch:
+            _fetch_agent(agent)
+    else:
+        executor = concurrent.futures.ThreadPoolExecutor(max_workers=5)
+        try:
+            list(executor.map(_fetch_agent, agents_to_fetch))
+        except Exception:  # pragma: no cover
+            raise
+        finally:
+            executor.shutdown(wait=False, cancel_futures=True)
+
     for agent in candidates:
         artifact_name = agent_ledger_artifact_name(request, agent)
-        if artifact_name not in artifact_cache:
-            response = dispatch_client.request(
-                [
-                    LEDGER_ARTIFACTS_ENDPOINT,
-                    "-X",
-                    "GET",
-                    "-f",
-                    f"name={artifact_name}",
-                    "-f",
-                    "per_page=100",
-                ]
-            )
-            artifact_cache[artifact_name] = bool(
-                _artifact_records(response, expected_name=artifact_name)
-            )
-        if artifact_cache[artifact_name]:
+        if artifact_cache.get(artifact_name):
             observed.add(agent)
     return frozenset(observed)
 

tests/test_agent_mention_router.py

@@ -371,3 +371,35 @@ def test_load_event_and_main_paths(tmp_path: Path, monkeypatch, capsys) -> None:
     )
     assert module.main(["--event-path", str(valid_path), "--dry-run"]) == 0
     assert captured[0][1]["dry_run"] is True
+
+def test_dispatched_agents_concurrent_path() -> None:
+    """The dispatched_agents function uses ThreadPoolExecutor for multiple agents."""
+    module = load_module()
+    request = module.parse_event(event("@cwl-noema-review @opencode-agent"))
+    assert request is not None
+    client = FakeClient()
+
+    # We want to force it to use ThreadPoolExecutor by providing multiple agents.
+    agents = ["cwl-noema-review", "opencode-agent"]
+
+    observed = module.dispatched_agents(
+        request,
+        dispatch_client=client,
+        agents=agents,
+    )
+    # The fake client returns an empty artifact array, so none are observed as dispatched.
+    assert observed == frozenset()
+
+    # Assert two artifact checks happened
+    artifact_calls = [c for c in client.calls if c[0][0].endswith("/actions/artifacts")]
+    assert len(artifact_calls) == 2
+
+    # Now verify the cache path
+    cache = {module.agent_ledger_artifact_name(request, "cwl-noema-review"): True}
+    observed = module.dispatched_agents(
+        request,
+        dispatch_client=client,
+        agents=["cwl-noema-review"],
+        ledger_artifact_cache=cache
+    )
+    assert observed == frozenset({"cwl-noema-review"})