diff --git a/external-connector/external_connector/main.py b/external-connector/external_connector/main.py
index fb12654..3fca53b 100644
--- a/external-connector/external_connector/main.py
+++ b/external-connector/external_connector/main.py
@@ -17,7 +17,7 @@ from external_connector.state import SidecarStateStore
 def build_app():
     home = Path(os.getenv("CONNECTOR_HOME", "/var/lib/external-connector"))
     store = SidecarStateStore(home / "state.json")
-    provider_name = os.getenv("CONNECTOR_PROVIDER", "fake")
+    provider_name = os.getenv("CONNECTOR_PROVIDER", "official")
     if provider_name == "official":
         provider = CompositeProvider([
             _weixin_provider(store),
diff --git a/external-connector/tests/test_main.py b/external-connector/tests/test_main.py
new file mode 100644
index 0000000..b384af4
--- /dev/null
+++ b/external-connector/tests/test_main.py
@@ -0,0 +1,24 @@
+from __future__ import annotations
+
+from external_connector import main
+
+
+def test_build_app_defaults_to_official_provider(monkeypatch, tmp_path) -> None:
+    monkeypatch.delenv("CONNECTOR_PROVIDER", raising=False)
+    monkeypatch.setenv("CONNECTOR_HOME", str(tmp_path))
+
+    app = main.build_app()
+    health = next(route.endpoint for route in app.routes if route.path == "/health")()
+
+    assert health["providerId"] == "composite"
+    assert [provider["providerId"] for provider in health["providers"]] == ["weixin_ilink", "feishu_bot"]
+
+
+def test_build_app_allows_explicit_fake_provider(monkeypatch, tmp_path) -> None:
+    monkeypatch.setenv("CONNECTOR_PROVIDER", "fake")
+    monkeypatch.setenv("CONNECTOR_HOME", str(tmp_path))
+
+    app = main.build_app()
+    health = next(route.endpoint for route in app.routes if route.path == "/health")()
+
+    assert health["providerId"] == "fake"