diff --git a/tests/conftest.py b/tests/conftest.py
index e7d2f76..a1e4aca 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,4 +1,6 @@
+import os
 import uuid
+import atexit
 import pytest
 from pathlib import Path
 from fastapi.testclient import TestClient
@@ -49,3 +51,43 @@ def client_with_isolation(isolated_data_root):
     yield client
 
     utils.get_data_root = original
+
+
+# ── E2E gate ──
+
+skip_no_integration = pytest.mark.skipif(
+    not os.environ.get("RUN_INTEGRATION"),
+    reason="Set RUN_INTEGRATION=1 to run E2E tests against real daemon",
+)
+
+
+# ── atexit 兜底清理 ──
+
+def _emergency_cleanup():
+    """进程退出时的最后防线：清理所有 e2e- 前缀的测试数据"""
+    try:
+        import requests
+        api_base = os.environ.get("API_BASE", "http://localhost:8083")
+        # 清理 e2e 前缀项目
+        resp = requests.get(f"{api_base}/api/projects", timeout=5)
+        if resp.ok:
+            for proj in resp.json():
+                pid = proj.get("id", "")
+                if pid.startswith("e2e-"):
+                    try:
+                        requests.delete(
+                            f"{api_base}/api/projects/{pid}?physical=true",
+                            timeout=5,
+                        )
+                    except Exception:
+                        pass
+        # 清理 e2e 前缀邮件
+        try:
+            requests.delete(f"{api_base}/api/mail?prefix=e2e-", timeout=5)
+        except Exception:
+            pass
+    except Exception:
+        pass
+
+
+atexit.register(_emergency_cleanup)