fix(mcp): satisfy type discipline gate and the merged input-schema key

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm/proxy/_experimental/mcp_server/caller_sign_in.py

@@ -136,7 +136,7 @@ def caller_sign_in_for(server: MCPServer, user_api_key_auth: UserAPIKeyAuth | No
     """The merged sign-in requirement for ``server``: the OBO server's own issuer/scopes plus every
     registered provider's contribution. ``None`` when nothing requires sign-in, which is also the gate the
     connect-time challenge branches on."""
-    contributions: Final = [
+    contributions: Final = tuple(
         contribution
         for contribution in (
             *(
@@ -147,7 +147,7 @@ def caller_sign_in_for(server: MCPServer, user_api_key_auth: UserAPIKeyAuth | No
             *(provider.caller_sign_in(server, user_api_key_auth) for provider in _providers()),
         )
         if contribution is not None
-    ]
+    )
     if not contributions:
         return None
     issuers: Final = tuple(dict.fromkeys(itertools.chain.from_iterable(c.issuers for c in contributions)))

litellm/proxy/_experimental/mcp_server/discoverable_endpoints.py

@@ -2625,9 +2625,9 @@ def _caller_sign_in_protected_resource_response(
     if sign_in is None or not sign_in.issuers:
         return None
     return {
-        "authorization_servers": list(sign_in.issuers),
+        "authorization_servers": sign_in.issuers,
         "resource": resource_url,
-        "scopes_supported": list(sign_in.scopes),
+        "scopes_supported": sign_in.scopes,
     }
 
 

litellm/proxy/_experimental/mcp_server/server.py

@@ -1589,7 +1589,7 @@ if MCP_AVAILABLE:
     ) -> bool:
         """Sign-in challenges are issued only on a single-server connect the key's grant admits, so a key
         without access gets the grant's 403 instead of a sign-in it could not use."""
-        if len(mcp_servers or []) != 1:
+        if len(mcp_servers or ()) != 1:
             return False
         allowed: Final = await operations._get_allowed_mcp_servers(
             user_api_key_auth=user_api_key_auth, mcp_servers=mcp_servers, client_ip=client_ip
@@ -1746,8 +1746,8 @@ if MCP_AVAILABLE:
                 await operations._get_allowed_mcp_servers(
                     user_api_key_auth=user_api_key_auth, mcp_servers=mcp_servers, client_ip=client_ip
                 )
-                if server and len(mcp_servers or []) == 1
-                else []
+                if server and len(mcp_servers or ()) == 1
+                else ()
             )
             if (
                 server

litellm/proxy/guardrails/guardrail_hooks/agent_365/agent_365.py

@@ -447,8 +447,10 @@ class Agent365Guardrail(CustomGuardrail):
         if not (self.default_on and server.keeps_caller_authorization):
             return None
         if user_api_key_auth is not None:
-            probe: Final[dict[str, Mapping[str, object]]] = {  # pyright: ignore[reportUnknownVariableType]  # UserAPIKeyAuth metadata dicts are untyped
-                "metadata": {
+            probe: Final[
+                dict[str, Mapping[str, object]]
+            ] = {  # mutable-ok: should_run_guardrail takes a mutable data dict  # pyright: ignore[reportUnknownVariableType]  # UserAPIKeyAuth metadata dicts are untyped
+                "metadata": {  # mutable-ok: should_run_guardrail takes a mutable data dict
                     "user_api_key_metadata": user_api_key_auth.metadata,  # pyright: ignore[reportUnknownMemberType]  # UserAPIKeyAuth.metadata is a raw dict
                     "user_api_key_team_metadata": user_api_key_auth.team_metadata,  # pyright: ignore[reportUnknownMemberType]  # UserAPIKeyAuth.team_metadata is a raw dict
                 }

tests/test_litellm/proxy/guardrails/guardrail_hooks/test_agent_365.py

@@ -193,9 +193,7 @@ def _make_guardrail(
     )
 
 
-def _default_fallback_guardrail(
-    handler: FakeHandler, exchanger: StubTokenExchanger | None = None
-) -> Agent365Guardrail:
+def _default_fallback_guardrail(handler: FakeHandler, exchanger: StubTokenExchanger | None = None) -> Agent365Guardrail:
     return _make_guardrail(handler, exchanger=exchanger)
 
 
@@ -416,7 +414,7 @@ class TestAllowFlow:
         handler: Final = FakeHandler([_allow_response()])
         guardrail: Final = _make_guardrail(handler)
         schema: Final = {"type": "object", "properties": {"to": {"type": "string"}}, "required": ["to"]}
-        await _run(guardrail, _mcp_data(mcp_tool_description="Send an email", mcp_tool_input_schema=schema))
+        await _run(guardrail, _mcp_data(mcp_tool_description="Send an email", mcp_input_schema=schema))
         assert handler.calls[0].json["tool"] == {
             "name": "send_email",
             "description": "Send an email",
@@ -431,7 +429,7 @@ class TestAllowFlow:
     async def test_evaluate_payload_omits_missing_or_malformed_tool_metadata(self, description, schema):
         handler: Final = FakeHandler([_allow_response()])
         guardrail: Final = _make_guardrail(handler)
-        await _run(guardrail, _mcp_data(mcp_tool_description=description, mcp_tool_input_schema=schema))
+        await _run(guardrail, _mcp_data(mcp_tool_description=description, mcp_input_schema=schema))
         assert handler.calls[0].json["tool"] == {"name": "send_email"}
 
     @pytest.mark.asyncio
@@ -617,9 +615,7 @@ class TestFailOpenOptIn:
     @pytest.mark.asyncio
     @pytest.mark.parametrize(("responses", "exchange_results"), AVAILABILITY_FAILURES)
     async def test_constructor_default_blocks_each_availability_failure_with_503(self, responses, exchange_results):
-        guardrail: Final = _default_fallback_guardrail(
-            FakeHandler(responses), StubTokenExchanger(exchange_results)
-        )
+        guardrail: Final = _default_fallback_guardrail(FakeHandler(responses), StubTokenExchanger(exchange_results))
         assert guardrail.unreachable_fallback == "fail_closed"
         with pytest.raises(HTTPException) as exc_info:
             await _run(guardrail, _mcp_data())
@@ -846,7 +842,9 @@ class TestUnreachableFallback:
 
     @pytest.mark.asyncio
     async def test_exchange_upstream_unavailable_follows_fail_open(self):
-        exchanger: Final = StubTokenExchanger([Error(CredError.of_upstream_unavailable("Entra throttled the exchange"))])
+        exchanger: Final = StubTokenExchanger(
+            [Error(CredError.of_upstream_unavailable("Entra throttled the exchange"))]
+        )
         handler: Final = FakeHandler([])
         guardrail: Final = _make_guardrail(handler, exchanger=exchanger, unreachable_fallback="fail_open")
         data: Final = _mcp_data()