diff --git a/src/api/toolchain_routes.py b/src/api/toolchain_routes.py
index 89d9c1a..f8e96da 100644
--- a/src/api/toolchain_routes.py
+++ b/src/api/toolchain_routes.py
@@ -8,6 +8,7 @@
 
 from __future__ import annotations
 
+import asyncio
 import hashlib
 import hmac
 import json
@@ -25,6 +26,7 @@ from fastapi import APIRouter, Header, Request, Response
 from src.blackboard.db import init_db
 from src.blackboard.models import Task
 from src.blackboard.operations import Blackboard
+from src.config.agents import AGENT_IDS
 from src.daemon.toolchain_templates import render_template
 from src.utils import get_data_root
 
@@ -41,6 +43,7 @@ router = APIRouter(tags=["toolchain"])
 _delivery_cache: Set[str] = set()
 _delivery_timestamps: List[Tuple[float, str]] = []
 _TTL_SECONDS = 7 * 24 * 3600
+_idempotency_lock = asyncio.Lock()
 
 
 def _is_duplicate(event: str, delivery: str) -> bool:
@@ -86,31 +89,32 @@ _GITEA_TOKEN: str = os.environ.get("GITEA_TOKEN", "")
 _GITEA_BASE = "http://192.168.2.154:3000/api/v1"
 
 
-async def _fetch_pr_files(repo: str, pr_number: int) -> List[str]:
-    """通过 Gitea API 获取 PR changed files 列表。
-
-    Args:
-        repo: 仓库路径（如 "sanguo/sanguo_moziplus_v2"）
-        pr_number: PR 编号
+async def _fetch_pr_files(repo: str, pr_number: int) -> Tuple[List[str], str]:
+    """获取 PR 文件列表，含重试机制。
 
     Returns:
-        文件路径列表
+        (文件列表, 错误信息) — 成功时错误信息为空字符串
     """
     if not _GITEA_TOKEN:
-        logger.warning("GITEA_TOKEN not set, cannot fetch PR files")
-        return []
+        return [], "GITEA_TOKEN 未配置"
 
     url = f"{_GITEA_BASE}/repos/{repo}/pulls/{pr_number}/files"
     headers = {"Authorization": f"token {_GITEA_TOKEN}"}
-    try:
-        async with httpx.AsyncClient(timeout=5.0) as client:
-            resp = await client.get(url, headers=headers)
-            resp.raise_for_status()
-            files: List[Dict[str, Any]] = resp.json()
-            return [f.get("filename", "") for f in files]
-    except Exception:
-        logger.warning("Failed to fetch PR files: %s/pulls/%d", repo, pr_number, exc_info=True)
-        return []
+    last_error = ""
+    for attempt in range(3):
+        try:
+            async with httpx.AsyncClient(timeout=5.0) as client:
+                resp = await client.get(url, headers=headers)
+                resp.raise_for_status()
+                files: List[Dict[str, Any]] = resp.json()
+                return [f.get("filename", "") for f in files], ""
+        except Exception as e:
+            last_error = str(e)
+            if attempt < 2:
+                await asyncio.sleep(0.5 * (attempt + 1))
+                logger.warning("Retry %d/3 fetching PR files: %s/pulls/%d", attempt + 1, repo, pr_number)
+    logger.warning("Failed to fetch PR files after 3 retries: %s/pulls/%d - %s", repo, pr_number, last_error)
+    return [], f"获取文件列表失败（重试3次）: {last_error}"
 
 
 # ---------------------------------------------------------------------------
@@ -136,10 +140,7 @@ def _calc_risk_level(changed_files: List[str]) -> str:
 # Mail 创建
 # ---------------------------------------------------------------------------
 
-KNOWN_AGENTS = {
-    "pangtong-fujunshi", "simayi-challenger", "zhangfei-dev",
-    "guanyu-dev", "zhaoyun-data", "jiangwei-infra",
-}
+
 
 MAIL_PROJECT_ID = "_mail"
 
@@ -173,7 +174,7 @@ def _send_mail(
     Raises:
         Exception: 数据库写入失败
     """
-    if to_agent not in KNOWN_AGENTS:
+    if to_agent not in AGENT_IDS:
         logger.warning("Unknown agent: %s, skipping mail", to_agent)
         return ""
 
@@ -235,9 +236,12 @@ async def _handle_pull_request(payload: Dict[str, Any]) -> None:
     branch = pr.get("head", {}).get("ref", "unknown")
 
     # 获取改动文件列表
-    changed_files = await _fetch_pr_files(repo, pr_number)
+    changed_files, fetch_error = await _fetch_pr_files(repo, pr_number)
     risk_level = _calc_risk_level(changed_files)
-    file_list = "\n".join(f"- {f}" for f in changed_files) if changed_files else "(无法获取文件列表)"
+    if fetch_error:
+        file_list = f"⚠️ {fetch_error}"
+    else:
+        file_list = "\n".join(f"- {f}" for f in changed_files) if changed_files else "(无文件变更)"
 
     text = render_template("review_request", {
         "repo": repo,
@@ -431,9 +435,10 @@ async def gitea_webhook(
 
     # 2. 幂等检查
     if x_gitea_event and x_gitea_delivery:
-        if _is_duplicate(x_gitea_event, x_gitea_delivery):
-            logger.debug("Duplicate webhook: %s/%s", x_gitea_event, x_gitea_delivery)
-            return Response(status_code=200, content="duplicate")
+        async with _idempotency_lock:
+            if _is_duplicate(x_gitea_event, x_gitea_delivery):
+                logger.debug("Duplicate webhook: %s/%s", x_gitea_event, x_gitea_delivery)
+                return Response(status_code=200, content="duplicate")
 
     # 3. 解析 payload
     try:
diff --git a/src/daemon/mail_notify.py b/src/daemon/mail_notify.py
index 90b9fc7..020415e 100644
--- a/src/daemon/mail_notify.py
+++ b/src/daemon/mail_notify.py
@@ -10,14 +10,10 @@ from typing import Optional
 
 from src.blackboard.models import Task
 from src.blackboard.operations import Blackboard
+from src.config.agents import AGENT_IDS
 
 logger = logging.getLogger(__name__)
 
-# 有效 Agent ID 集合（用于校验通知目标）
-_VALID_AGENT_IDS = frozenset({
-    "pangtong-fujunshi", "simayi-challenger", "zhangfei-dev",
-    "guanyu-dev", "zhaoyun-data", "jiangwei-infra",
-})
 
 # 邮件通知正文模板（统一模板，包含所有可能的失败原因和建议）
 _NOTIFY_TEMPLATE = """你的邮件投递失败了。
@@ -76,7 +72,7 @@ def notify_mail_failed(db_path: Path, original_mail_id: str,
 
         # 发件人不是有效 Agent（如 system）→ 通知庞统代处理，不触发广播
         target_agent = from_agent
-        if from_agent not in _VALID_AGENT_IDS:
+        if from_agent not in AGENT_IDS:
             logger.warning("Mail %s: sender '%s' is not a valid agent, routing failure notice to pangtong-fujunshi",
                            original_mail_id, from_agent)
             target_agent = "pangtong-fujunshi"