fix(app-server): preserve known method detection

Author: gersmann

codex/app_server/_protocol_helpers.py

@@ -152,16 +152,21 @@ def _build_known_methods(*, root_model: type[BaseModel]) -> frozenset[str]:
     root_field = getattr(root_model, "model_fields", {}).get("root")
     if root_field is None:
         return frozenset()
+    annotation = _unwrap_type_alias(root_field.annotation)
     methods = {
         method
-        for candidate in get_args(root_field.annotation)
+        for candidate in get_args(annotation)
         if isinstance(candidate, type) and issubclass(candidate, BaseModel)
         for method in [_candidate_method_literal(candidate)]
         if method is not None
     }
     return frozenset(methods)
 
 
+def _unwrap_type_alias(annotation: object) -> object:
+    return getattr(annotation, "__value__", annotation)
+
+
 def _candidate_method_literal(candidate: type[BaseModel]) -> str | None:
     model_fields = getattr(candidate, "model_fields", None)
     if not isinstance(model_fields, dict) or "method" not in model_fields:

tests/test_app_server_helpers.py

@@ -85,6 +85,14 @@ def test_parse_notification_rejects_unknown_methods_in_strict_mode() -> None:
         parse_notification({"method": "custom/notify", "params": {"ok": True}}, strict=True)
 
 
+def test_parse_notification_rejects_malformed_known_methods_in_non_strict_mode() -> None:
+    with pytest.raises(AppServerProtocolError, match="turn/completed"):
+        parse_notification(
+            {"method": "turn/completed", "params": {"bad": True}},
+            strict=False,
+        )
+
+
 def test_parse_server_request_allows_generic_unknown_methods_in_non_strict_mode() -> None:
     parsed = parse_server_request(
         {"id": "req-1", "method": "custom/request", "params": {"ok": True}},
@@ -96,6 +104,14 @@ def test_parse_server_request_allows_generic_unknown_methods_in_non_strict_mode(
     assert request_id(parsed) == "req-1"
 
 
+def test_parse_server_request_rejects_malformed_known_methods_in_non_strict_mode() -> None:
+    with pytest.raises(AppServerProtocolError, match="item/tool/call"):
+        parse_server_request(
+            {"id": "req-1", "method": "item/tool/call", "params": {"bad": True}},
+            strict=False,
+        )
+
+
 def test_parse_server_request_handles_permissions_approval_request() -> None:
     parsed = parse_server_request(
         {