Fix type errors for ty 0.0.1-alpha.31 upgrade (#2561)

* Fix type errors for ty 0.0.1-alpha.31 upgrade

Add type ignores and fixes for ty's stricter checking:
- Path(None) guards in cli.py
- isinstance checks for ElicitRequestFormParams (URL elicitation support)
- TODO(ty) comments for match/isinstance narrowing bugs
- Method override type ignores for generic covariance
- Starlette Middleware typing workarounds
- Dynamic type construction ignores in json_schema_type.py

* Fix remaining type errors for ty 0.0.1-alpha.31

- Add asserts for optional attribute access in tests
- Add type ignores for dynamic httpx transport internals
- Add TODO(ty) comments for `in` operator on str|bytes
- Add TODO(ty) comments for Starlette Middleware typing
- Use cast for prompt.fn async validation in server.py

* Upgrade ty to 0.0.1-alpha.31

Fixes additional test file type errors discovered after upgrade.

pyproject.toml

@@ -72,7 +72,7 @@ dev = [
     "pytest-timeout>=2.4.0",
     "pytest-xdist>=3.6.1",
     "ruff>=0.12.8",
-    "ty==0.0.1a25",
+    "ty==0.0.1a31",
     "prek>=0.2.12",
 ]
 

src/fastmcp/cli/cli.py

@@ -103,7 +103,7 @@ def version(
         "MCP version": importlib.metadata.version("mcp"),
         "Python version": platform.python_version(),
         "Platform": platform.platform(),
-        "FastMCP root path": Path(fastmcp.__file__).resolve().parents[1],
+        "FastMCP root path": Path(fastmcp.__file__ or ".").resolve().parents[1],
     }
 
     g = Table.grid(padding=(0, 1))
@@ -819,11 +819,13 @@ async def prepare(
             )
             sys.exit(1)
 
+    assert config_path is not None
     config_file = Path(config_path)
     if not config_file.exists():
         logger.error(f"Configuration file not found: {config_path}")
         sys.exit(1)
 
+    assert output_dir is not None
     output_path = Path(output_dir)
 
     try:

src/fastmcp/client/elicitation.py

@@ -7,7 +7,7 @@ import mcp.types
 from mcp import ClientSession
 from mcp.client.session import ElicitationFnT
 from mcp.shared.context import LifespanContextT, RequestContext
-from mcp.types import ElicitRequestParams
+from mcp.types import ElicitRequestFormParams, ElicitRequestParams
 from mcp.types import ElicitResult as MCPElicitResult
 from pydantic_core import to_jsonable_python
 from typing_extensions import TypeVar
@@ -26,7 +26,8 @@ class ElicitResult(MCPElicitResult, Generic[T]):
 ElicitationHandler: TypeAlias = Callable[
     [
         str,  # message
-        type[T],  # a class for creating a structured response
+        type[T]
+        | None,  # a class for creating a structured response (None for URL elicitation)
         ElicitRequestParams,
         RequestContext[ClientSession, LifespanContextT],
     ],
@@ -42,10 +43,15 @@ def create_elicitation_callback(
         params: ElicitRequestParams,
     ) -> MCPElicitResult | mcp.types.ErrorData:
         try:
-            if params.requestedSchema == {"type": "object", "properties": {}}:
-                response_type = None
+            # requestedSchema only exists on ElicitRequestFormParams, not ElicitRequestURLParams
+            if isinstance(params, ElicitRequestFormParams):
+                if params.requestedSchema == {"type": "object", "properties": {}}:
+                    response_type = None
+                else:
+                    response_type = json_schema_to_type(params.requestedSchema)
             else:
-                response_type = json_schema_to_type(params.requestedSchema)
+                # URL-based elicitation doesn't have a schema
+                response_type = None
 
             result = await elicitation_handler(
                 params.message, response_type, params, context

src/fastmcp/client/messages.py

@@ -35,16 +35,18 @@ class MessageHandler:
             # requests
             case RequestResponder():
                 # handle all requests
-                await self.on_request(message)
+                # TODO(ty): remove when ty supports match statement narrowing
+                await self.on_request(message)  # type: ignore[arg-type]
 
                 # handle specific requests
-                match message.request.root:
+                # TODO(ty): remove type ignores when ty supports match statement narrowing
+                match message.request.root:  # type: ignore[union-attr]
                     case mcp.types.PingRequest():
-                        await self.on_ping(message.request.root)
+                        await self.on_ping(message.request.root)  # type: ignore[union-attr]
                     case mcp.types.ListRootsRequest():
-                        await self.on_list_roots(message.request.root)
+                        await self.on_list_roots(message.request.root)  # type: ignore[union-attr]
                     case mcp.types.CreateMessageRequest():
-                        await self.on_create_message(message.request.root)
+                        await self.on_create_message(message.request.root)  # type: ignore[union-attr]
 
             # notifications
             case mcp.types.ServerNotification():

src/fastmcp/client/roots.py

@@ -34,7 +34,8 @@ def create_roots_callback(
     handler: RootsList | RootsHandler,
 ) -> ListRootsFnT:
     if isinstance(handler, list):
-        return _create_roots_callback_from_roots(handler)
+        # TODO(ty): remove when ty supports isinstance union narrowing
+        return _create_roots_callback_from_roots(handler)  # type: ignore[arg-type]
     elif inspect.isfunction(handler):
         return _create_roots_callback_from_fn(handler)
     else:

src/fastmcp/client/tasks.py

@@ -201,7 +201,7 @@ class Task(abc.ABC, Generic[TaskResultT]):
                 result = callback(status)
                 if inspect.isawaitable(result):
                     # Fire and forget async callbacks
-                    asyncio.create_task(result)  # noqa: RUF006
+                    asyncio.create_task(result)  # type: ignore[arg-type] # noqa: RUF006
             except Exception as e:
                 logger.warning(f"Task callback error: {e}", exc_info=True)
 

src/fastmcp/client/transports.py

@@ -375,7 +375,8 @@ class StdioTransport(ClientTransport):
                 env=self.env,
                 cwd=self.cwd,
                 log_file=self.log_file,
-                session_kwargs=session_kwargs,
+                # TODO(ty): remove when ty supports Unpack[TypedDict] inference
+                session_kwargs=session_kwargs,  # type: ignore[arg-type]
                 ready_event=self._ready_event,
                 stop_event=self._stop_event,
                 session_future=session_future,

src/fastmcp/experimental/sampling/handlers/openai.py

@@ -164,7 +164,7 @@ class OpenAISamplingHandler(BaseLLMSamplingHandler):
     ) -> ChatModel:
         for model_option in self._iter_models_from_preferences(model_preferences):
             if model_option in get_args(ChatModel):
-                chosen_model: ChatModel = model_option  # pyright: ignore[reportAssignmentType]
+                chosen_model: ChatModel = model_option  # type: ignore[assignment]
                 return chosen_model
 
         return self.default_model

src/fastmcp/prompts/prompt.py

@@ -206,7 +206,7 @@ class FunctionPrompt(Prompt):
             fn = fn.__call__
         # if the fn is a staticmethod, we need to work with the underlying function
         if isinstance(fn, staticmethod):
-            fn = fn.__func__
+            fn = fn.__func__  # type: ignore[assignment]
 
         # Validate that task=True requires async functions (after unwrapping)
         if task and not inspect.iscoroutinefunction(fn):

src/fastmcp/server/auth/auth.py

@@ -189,12 +189,13 @@ class AuthProvider(TokenVerifierProtocol):
         Returns:
             List of Starlette Middleware instances to apply to the HTTP app
         """
+        # TODO(ty): remove type ignores when ty supports Starlette Middleware typing
         return [
             Middleware(
-                AuthenticationMiddleware,
+                AuthenticationMiddleware,  # type: ignore[arg-type]
                 backend=BearerAuthBackend(self),
             ),
-            Middleware(AuthContextMiddleware),
+            Middleware(AuthContextMiddleware),  # type: ignore[arg-type]
         ]
 
     def _get_resource_url(self, path: str | None = None) -> AnyHttpUrl | None:

src/fastmcp/server/auth/oauth_proxy.py

@@ -1006,7 +1006,8 @@ class OAuthProxy(OAuthProvider):
         # Store transaction data for IdP callback processing
         if client.client_id is None:
             raise AuthorizeError(
-                error="invalid_client", error_description="Client ID is required"
+                error="invalid_client",  # type: ignore[arg-type]
+                error_description="Client ID is required",
             )
         transaction = OAuthTransaction(
             txn_id=txn_id,
@@ -1088,7 +1089,8 @@ class OAuthProxy(OAuthProvider):
         # Create authorization code object with PKCE challenge
         if client.client_id is None:
             raise AuthorizeError(
-                error="invalid_client", error_description="Client ID is required"
+                error="invalid_client",  # type: ignore[arg-type]
+                error_description="Client ID is required",
             )
         return AuthorizationCode(
             code=authorization_code,
@@ -1512,7 +1514,7 @@ class OAuthProxy(OAuthProvider):
     # Token Validation
     # -------------------------------------------------------------------------
 
-    async def load_access_token(self, token: str) -> AccessToken | None:
+    async def load_access_token(self, token: str) -> AccessToken | None:  # type: ignore[override]
         """Validate FastMCP JWT by swapping for upstream token.
 
         This implements the token swap pattern:

src/fastmcp/server/auth/providers/in_memory.py

@@ -284,7 +284,7 @@ class InMemoryOAuthProvider(OAuthProvider):
             scope=" ".join(scopes),
         )
 
-    async def load_access_token(self, token: str) -> AccessToken | None:
+    async def load_access_token(self, token: str) -> AccessToken | None:  # type: ignore[override]
         token_obj = self.access_tokens.get(token)
         if token_obj:
             if token_obj.expires_at is not None and token_obj.expires_at < time.time():
@@ -295,7 +295,7 @@ class InMemoryOAuthProvider(OAuthProvider):
             return token_obj
         return None
 
-    async def verify_token(self, token: str) -> AccessToken | None:
+    async def verify_token(self, token: str) -> AccessToken | None:  # type: ignore[override]
         """
         Verify a bearer token and return access info if valid.
 

src/fastmcp/server/auth/providers/oci.py

@@ -171,7 +171,7 @@ class OCIProvider(OIDCProxy):
             allowed_client_redirect_uris: List of allowed redirect URI patterns for MCP clients.
         """
 
-        overrides = {
+        overrides: dict[str, object] = {
             k: v
             for k, v in {
                 "config_url": config_url,
@@ -187,7 +187,7 @@ class OCIProvider(OIDCProxy):
             }.items()
             if v is not NotSet
         }
-        settings = OCIProviderSettings(**overrides)
+        settings = OCIProviderSettings(**overrides)  # type: ignore[arg-type]
 
         if not settings.config_url:
             raise ValueError(

src/fastmcp/server/context.py

@@ -388,7 +388,7 @@ class Context:
             session_id = str(uuid4())
 
         # Save the session id to the session attributes
-        session._fastmcp_id = session_id
+        session._fastmcp_id = session_id  # type: ignore[attr-defined]
         return session_id
 
     @property
@@ -540,7 +540,7 @@ class Context:
                     maxTokens=max_tokens,
                     modelPreferences=_parse_model_preferences(model_preferences),
                 ),
-                self.request_context,
+                self.request_context,  # type: ignore[arg-type]
             )
 
             if inspect.isawaitable(create_message_result):

src/fastmcp/server/elicitation.py

@@ -37,13 +37,13 @@ class ElicitationJsonSchema(GenerateJsonSchema):
     Optionally adds enumNames for better UI display when available.
     """
 
-    def generate_inner(self, schema: core_schema.CoreSchema) -> JsonSchemaValue:
+    def generate_inner(self, schema: core_schema.CoreSchema) -> JsonSchemaValue:  # type: ignore[override]
         """Override to prevent ref generation for enums."""
         # For enum schemas, bypass the ref mechanism entirely
         if schema["type"] == "enum":
             # Directly call our custom enum_schema without going through handler
             # This prevents the ref/defs mechanism from being invoked
-            return self.enum_schema(schema)
+            return self.enum_schema(schema)  # type: ignore[arg-type]
         # For all other types, use the default implementation
         return super().generate_inner(schema)
 

src/fastmcp/server/http.py

@@ -117,7 +117,8 @@ def create_base_app(
         A Starlette application
     """
     # Always add RequestContextMiddleware as the outermost middleware
-    middleware.insert(0, Middleware(RequestContextMiddleware))
+    # TODO(ty): remove type ignore when ty supports Starlette Middleware typing
+    middleware.insert(0, Middleware(RequestContextMiddleware))  # type: ignore[arg-type]
 
     return StarletteWithLifespan(
         routes=routes,

src/fastmcp/server/proxy.py

@@ -14,6 +14,7 @@ from mcp.shared.exceptions import McpError
 from mcp.types import (
     METHOD_NOT_FOUND,
     BlobResourceContents,
+    ElicitRequestFormParams,
     GetPromptResult,
     TextResourceContents,
 )
@@ -363,7 +364,7 @@ class ProxyTemplate(ResourceTemplate, MirroredComponent):
         self._client = client
 
     @classmethod
-    def from_mcp_template(
+    def from_mcp_template(  # type: ignore[override]
         cls, client: Client, mcp_template: mcp.types.ResourceTemplate
     ) -> ProxyTemplate:
         """Factory method to create a ProxyTemplate from a raw MCP template schema."""
@@ -454,7 +455,7 @@ class ProxyPrompt(Prompt, MirroredComponent):
             _mirrored=True,
         )
 
-    async def render(self, arguments: dict[str, Any]) -> list[PromptMessage]:
+    async def render(self, arguments: dict[str, Any]) -> list[PromptMessage]:  # type: ignore[override]
         """Render the prompt by making a call through the client."""
         async with self._client:
             result = await self._client.get_prompt(self.name, arguments)
@@ -567,7 +568,8 @@ class ProxyClient(Client[ClientTransportT]):
         return mcp.types.CreateMessageResult(
             role="assistant",
             model="fastmcp-client",
-            content=content,
+            # TODO(ty): remove when ty supports isinstance exclusion narrowing
+            content=content,  # type: ignore[arg-type]
         )
 
     @classmethod
@@ -582,9 +584,15 @@ class ProxyClient(Client[ClientTransportT]):
         A handler that forwards the elicitation request from the remote server to the proxy's connected clients and relays the response back to the remote server.
         """
         ctx = get_context()
+        # requestedSchema only exists on ElicitRequestFormParams, not ElicitRequestURLParams
+        requested_schema = (
+            params.requestedSchema
+            if isinstance(params, ElicitRequestFormParams)
+            else {"type": "object", "properties": {}}
+        )
         result = await ctx.session.elicit(
             message=message,
-            requestedSchema=params.requestedSchema,
+            requestedSchema=requested_schema,
             related_request_id=ctx.request_id,
         )
         return ElicitResult(action=result.action, content=result.content)
@@ -628,7 +636,7 @@ class StatefulProxyClient(ProxyClient[ClientTransportT]):
         super().__init__(*args, **kwargs)
         self._caches: dict[ServerSession, Client[ClientTransportT]] = {}
 
-    async def __aexit__(self, exc_type, exc_value, traceback) -> None:
+    async def __aexit__(self, exc_type, exc_value, traceback) -> None:  # type: ignore[override]
         """
         The stateful proxy client will be forced disconnected when the session is exited.
         So we do nothing here.

src/fastmcp/server/server.py

@@ -407,7 +407,8 @@ class FastMCP(Generic[LifespanResultT]):
 
                 for prompt in self._prompt_manager._prompts.values():
                     if isinstance(prompt, FunctionPrompt) and prompt.task:
-                        docket.register(prompt.fn)
+                        # task=True requires async fn (validated at creation time)
+                        docket.register(cast(Callable[..., Awaitable[Any]], prompt.fn))
 
                 for resource in self._resource_manager._resources.values():
                     if isinstance(resource, FunctionResource) and resource.task:

src/fastmcp/utilities/components.py

@@ -96,7 +96,7 @@ class FastMCPComponent(FastMCPBaseModel):
 
         return meta or None
 
-    def model_copy(
+    def model_copy(  # type: ignore[override]
         self,
         *,
         update: dict[str, Any] | None = None,
@@ -137,7 +137,7 @@ class FastMCPComponent(FastMCPBaseModel):
         """Disable the component."""
         self.enabled = False
 
-    def copy(self) -> Self:
+    def copy(self) -> Self:  # type: ignore[override]
         """Create a copy of the component."""
         return self.model_copy()
 
@@ -173,7 +173,7 @@ class MirroredComponent(FastMCPComponent):
             )
         super().disable()
 
-    def copy(self) -> Self:
+    def copy(self) -> Self:  # type: ignore[override]
         """Create a copy of the component that can be modified."""
         # Create a copy and mark it as not mirrored
         copied = self.model_copy()

src/fastmcp/utilities/json_schema_type.py

@@ -248,7 +248,7 @@ def _create_numeric_type(
         if v is not None
     }
 
-    return Annotated[base, Field(**constraints)] if constraints else base
+    return Annotated[base, Field(**constraints)] if constraints else base  # type: ignore[return-value]
 
 
 def _create_enum(name: str, values: list[Any]) -> type:
@@ -265,8 +265,8 @@ def _create_array_type(
     if isinstance(items, list):
         # Handle positional item schemas
         item_types = [_schema_to_type(s, schemas) for s in items]
-        combined = Union[tuple(item_types)]  # type: ignore # noqa: UP007
-        base = list[combined]
+        combined = Union[tuple(item_types)]  # type: ignore[arg-type] # noqa: UP007
+        base = list[combined]  # type: ignore[valid-type]
     else:
         # Handle single item schema
         item_type = _schema_to_type(items, schemas)
@@ -282,7 +282,7 @@ def _create_array_type(
         if v is not None
     }
 
-    return Annotated[base, Field(**constraints)] if constraints else base
+    return Annotated[base, Field(**constraints)] if constraints else base  # type: ignore[return-value]
 
 
 def _return_Any() -> Any:

src/fastmcp/utilities/mcp_server_config/v1/mcp_server_config.py

@@ -192,7 +192,7 @@ class MCPServerConfig(BaseModel):
         """
         if isinstance(v, dict):
             return FileSystemSource(**v)
-        return v
+        return v  # type: ignore[return-value]
 
     @field_validator("environment", mode="before")
     @classmethod

tests/client/test_client.py

@@ -159,6 +159,7 @@ async def test_call_tool_with_meta():
         from fastmcp.server.dependencies import get_context
 
         context = get_context()
+        assert context.request_context is not None
         meta = context.request_context.meta
 
         # Return the meta data as a dict

tests/client/test_elicitation.py

@@ -3,7 +3,7 @@ from enum import Enum
 from typing import Literal
 
 import pytest
-from mcp.types import ElicitRequestParams
+from mcp.types import ElicitRequestFormParams, ElicitRequestParams
 from pydantic import BaseModel, Field
 from typing_extensions import TypedDict
 
@@ -153,6 +153,7 @@ class TestScalarResponseTypes:
         async def elicitation_handler(
             message, response_type, params: ElicitRequestParams, ctx
         ):
+            assert isinstance(params, ElicitRequestFormParams)
             assert params.requestedSchema == {"type": "object", "properties": {}}
             assert response_type is None
             return ElicitResult(action="accept")

tests/client/transports/test_transports.py

@@ -15,8 +15,9 @@ async def test_oauth_uses_same_client_as_transport_streamable_http():
     )
 
     async with transport.auth.httpx_client_factory() as httpx_client:  # type: ignore[attr-defined]
+        assert httpx_client._transport is not None
         assert (
-            httpx_client._transport._pool._ssl_context.verify_mode
+            httpx_client._transport._pool._ssl_context.verify_mode  # type: ignore[attr-defined]
             == VerifyMode.CERT_NONE
         )
 
@@ -31,7 +32,8 @@ async def test_oauth_uses_same_client_as_transport_sse():
     )
 
     async with transport.auth.httpx_client_factory() as httpx_client:  # type: ignore[attr-defined]
+        assert httpx_client._transport is not None
         assert (
-            httpx_client._transport._pool._ssl_context.verify_mode
+            httpx_client._transport._pool._ssl_context.verify_mode  # type: ignore[attr-defined]
             == VerifyMode.CERT_NONE
         )

tests/resources/test_resource_template.py

@@ -779,8 +779,9 @@ class TestQueryParameterTypeCoercion:
         )
 
         content = await resource.read()
-        assert '"page":5' in content
-        assert '"type":"int"' in content
+        # TODO(ty): remove when ty supports `in` on str | bytes
+        assert '"page":5' in content  # type: ignore[operator]
+        assert '"type":"int"' in content  # type: ignore[operator]
 
     async def test_bool_coercion(self):
         """Test boolean type coercion for query parameters."""
@@ -800,7 +801,8 @@ class TestQueryParameterTypeCoercion:
             {"name": "feature", "enabled": "true"},
         )
         content = await resource.read()
-        assert '"enabled":true' in content
+        # TODO(ty): remove when ty supports `in` on str | bytes
+        assert '"enabled":true' in content  # type: ignore[operator]
 
         # Test false value
         resource = await template.create_resource(
@@ -808,7 +810,8 @@ class TestQueryParameterTypeCoercion:
             {"name": "feature", "enabled": "false"},
         )
         content = await resource.read()
-        assert '"enabled":false' in content
+        # TODO(ty): remove when ty supports `in` on str | bytes
+        assert '"enabled":false' in content  # type: ignore[operator]
 
     async def test_float_coercion(self):
         """Test float type coercion for query parameters."""
@@ -832,8 +835,9 @@ class TestQueryParameterTypeCoercion:
         )
 
         content = await resource.read()
-        assert '"threshold":0.95' in content
-        assert '"type":"float"' in content
+        # TODO(ty): remove when ty supports `in` on str | bytes
+        assert '"threshold":0.95' in content  # type: ignore[operator]
+        assert '"type":"float"' in content  # type: ignore[operator]
 
 
 class TestQueryParameterValidation:
@@ -892,8 +896,9 @@ class TestQueryParameterWithDefaults:
         )
 
         content = await resource.read()
-        assert '"format":"json"' in content
-        assert '"verbose":false' in content
+        # TODO(ty): remove when ty supports `in` on str | bytes
+        assert '"format":"json"' in content  # type: ignore[operator]
+        assert '"verbose":false' in content  # type: ignore[operator]
 
     async def test_partial_query_params(self):
         """Test providing only some query parameters."""
@@ -916,9 +921,10 @@ class TestQueryParameterWithDefaults:
         )
 
         content = await resource.read()
-        assert '"format":"json"' in content  # default
-        assert '"limit":20' in content  # provided
-        assert '"offset":0' in content  # default
+        # TODO(ty): remove when ty supports `in` on str | bytes
+        assert '"format":"json"' in content  # type: ignore[operator]  # default
+        assert '"limit":20' in content  # type: ignore[operator]  # provided
+        assert '"offset":0' in content  # type: ignore[operator]  # default
 
 
 class TestQueryParameterWithWildcards:
@@ -951,6 +957,7 @@ class TestQueryParameterWithWildcards:
         )
 
         content = await resource.read()
-        assert '"path":"src/test/data.txt"' in content
-        assert '"encoding":"utf-8"' in content  # default
-        assert '"lines":50' in content  # provided
+        # TODO(ty): remove when ty supports `in` on str | bytes
+        assert '"path":"src/test/data.txt"' in content  # type: ignore[operator]
+        assert '"encoding":"utf-8"' in content  # type: ignore[operator]  # default
+        assert '"lines":50' in content  # type: ignore[operator]  # provided

tests/server/auth/providers/test_azure.py

@@ -851,6 +851,7 @@ class TestOIDCScopeHandling:
         # required_scopes (used for validation) excludes OIDC scopes
         assert provider.required_scopes == ["read"]
         # But valid_scopes (advertised to clients) includes all scopes
+        assert provider.client_registration_options is not None
         assert provider.client_registration_options.valid_scopes == [
             "read",
             "openid",

tests/server/auth/test_jwt_provider.py

@@ -550,7 +550,7 @@ class TestBearerTokenJWKS:
         mock_jwks_data: JWKSData,
         httpx_mock: HTTPXMock,
     ):
-        mock_jwks_data["keys"] = [
+        mock_jwks_data["keys"] = [  # type: ignore[typeddict-item]
             {
                 "kid": "test-key-1",
                 "alg": "RS256",

tests/server/auth/test_oauth_proxy_redirect_validation.py

@@ -14,7 +14,7 @@ class MockTokenVerifier(TokenVerifier):
     def __init__(self):
         self.required_scopes = []
 
-    async def verify_token(self, token: str) -> dict | None:
+    async def verify_token(self, token: str) -> dict | None:  # type: ignore[override]
         return {"sub": "test-user"}
 
 

tests/server/http/test_http_middleware.py

@@ -55,9 +55,12 @@ async def test_sse_app_with_custom_middleware():
     server = FastMCP(name="TestServer")
 
     # Create custom middleware
+    # TODO(ty): remove when Starlette Middleware typing is supported
     custom_middleware = [
         Middleware(
-            HeaderMiddleware, header_name="X-Custom-Header", header_value="test-value"
+            HeaderMiddleware,  # type: ignore[arg-type]
+            header_name="X-Custom-Header",
+            header_value="test-value",
         )
     ]
 
@@ -85,9 +88,12 @@ async def test_streamable_http_app_with_custom_middleware():
     server = FastMCP(name="TestServer")
 
     # Create custom middleware
+    # TODO(ty): remove when Starlette Middleware typing is supported
     custom_middleware = [
         Middleware(
-            HeaderMiddleware, header_name="X-Custom-Header", header_value="test-value"
+            HeaderMiddleware,  # type: ignore[arg-type]
+            header_name="X-Custom-Header",
+            header_value="test-value",
         )
     ]
 
@@ -115,8 +121,13 @@ async def test_create_sse_app_with_custom_middleware():
     server = FastMCP(name="TestServer")
 
     # Create custom middleware
+    # TODO(ty): remove when Starlette Middleware typing is supported
     custom_middleware = [
-        Middleware(RequestModifierMiddleware, key="modified_by", value="middleware")
+        Middleware(
+            RequestModifierMiddleware,  # type: ignore[arg-type]
+            key="modified_by",
+            value="middleware",
+        )
     ]
 
     # Add a test route
@@ -150,8 +161,13 @@ async def test_create_streamable_http_app_with_custom_middleware():
     server = FastMCP(name="TestServer")
 
     # Create custom middleware
+    # TODO(ty): remove when Starlette Middleware typing is supported
     custom_middleware = [
-        Middleware(RequestModifierMiddleware, key="modified_by", value="middleware")
+        Middleware(
+            RequestModifierMiddleware,  # type: ignore[arg-type]
+            key="modified_by",
+            value="middleware",
+        )
     ]
 
     # Add a test route
@@ -184,12 +200,17 @@ async def test_multiple_middleware_ordering():
     server = FastMCP(name="TestServer")
 
     # Create multiple middleware
+    # TODO(ty): remove when Starlette Middleware typing is supported
     custom_middleware = [
         Middleware(
-            HeaderMiddleware, header_name="X-First-Header", header_value="first"
+            HeaderMiddleware,  # type: ignore[arg-type]
+            header_name="X-First-Header",
+            header_value="first",
         ),
         Middleware(
-            HeaderMiddleware, header_name="X-Second-Header", header_value="second"
+            HeaderMiddleware,  # type: ignore[arg-type]
+            header_name="X-Second-Header",
+            header_value="second",
         ),
     ]
 

tests/server/proxy/test_proxy_client.py

@@ -3,7 +3,13 @@ from typing import cast
 
 import pytest
 from anyio import create_task_group
-from mcp.types import LoggingLevel, ModelHint, ModelPreferences, TextContent
+from mcp.types import (
+    ElicitRequestFormParams,
+    LoggingLevel,
+    ModelHint,
+    ModelPreferences,
+    TextContent,
+)
 from pydantic import BaseModel, Field
 
 from fastmcp import Client, Context, FastMCP
@@ -181,6 +187,7 @@ class TestProxyClient:
             elicitation_handler_called = True
             assert message == "What is your name?"
             assert "Person" in str(response_type)
+            assert isinstance(params, ElicitRequestFormParams)
             assert params.requestedSchema == {
                 "title": "Person",
                 "type": "object",
@@ -377,6 +384,7 @@ class TestProxyClient:
             ctx: RequestContext,
         ):
             # Verify the schema is correct - acknowledge should have default=False, not be nullable
+            assert isinstance(params, ElicitRequestFormParams)
             schema = params.requestedSchema
             assert schema["properties"]["acknowledge"]["type"] == "boolean"
             assert schema["properties"]["acknowledge"]["default"] is False

tests/server/proxy/test_proxy_server.py

@@ -143,7 +143,7 @@ async def test_proxy_with_async_client_factory():
     proxy = FastMCPProxy(client_factory=async_factory)
     assert isinstance(proxy, FastMCPProxy)
     assert inspect.iscoroutinefunction(proxy.client_factory)
-    client = await proxy.client_factory()
+    client = await proxy.client_factory()  # type: ignore[misc]
     assert isinstance(client, Client)
     assert isinstance(client.transport, StreamableHttpTransport)
     assert client.transport.url == "http://example.com/mcp/"  # type: ignore[attr-defined]

tests/server/test_server_docket.py

@@ -159,6 +159,7 @@ async def test_user_lifespan_still_works_with_docket():
     def check_both(docket: Docket = CurrentDocket()) -> str:
         assert isinstance(docket, Docket)
         ctx = get_context()
+        assert ctx.request_context is not None
         lifespan_data = ctx.request_context.lifespan_context
         assert lifespan_data.get("custom_data") == "test_value"
         return HUZZAH

tests/server/test_server_lifespan.py

@@ -62,6 +62,7 @@ class TestServerLifespan:
         @mcp.tool
         def get_db_info(ctx: Context) -> str:
             # Access the server lifespan context
+            assert ctx.request_context is not None
             lifespan_context = ctx.request_context.lifespan_context
             return lifespan_context.get("db_connection", "no_db")
 

tests/utilities/test_json_schema_type.py

@@ -1149,7 +1149,7 @@ class TestEdgeCases:
         Type = json_schema_to_type(schema)
         validator = TypeAdapter(Type)
         result = validator.validate_python({"name": "test"})
-        assert result.name == "test"
+        assert result.name == "test"  # type: ignore[attr-defined]
 
     def test_recursive_defaults(self):
         schema = {
@@ -1165,8 +1165,8 @@ class TestEdgeCases:
         Type = json_schema_to_type(schema)
         validator = TypeAdapter(Type)
         result = validator.validate_python({})
-        assert result.node.value == "default"
-        assert result.node.next is None
+        assert result.node.value == "default"  # type: ignore[attr-defined]
+        assert result.node.next is None  # type: ignore[attr-defined]
 
     def test_mixed_type_array(self):
         schema = {
@@ -1277,9 +1277,9 @@ class TestNameHandling:
         result = validator.validate_python(
             {"name": "parent", "child": {"name": "child", "child": None}}
         )
-        assert result.name == "parent"
-        assert result.child.name == "child"
-        assert result.child.child is None
+        assert result.name == "parent"  # type: ignore[attr-defined]
+        assert result.child.name == "child"  # type: ignore[attr-defined]
+        assert result.child.child is None  # type: ignore[attr-defined]
 
 
 class TestAdditionalProperties:
@@ -1459,17 +1459,17 @@ class TestAdditionalProperties:
         result = validator.validate_python(data)
 
         # Check top-level extra field (BaseModel)
-        assert result.top_level_extra == "preserved"
+        assert result.top_level_extra == "preserved"  # type: ignore[attr-defined]
 
         # Check nested user extra field (BaseModel)
-        assert result.user.name == "Alice"
-        assert result.user.extra_user_field == "value"
+        assert result.user.name == "Alice"  # type: ignore[attr-defined]
+        assert result.user.extra_user_field == "value"  # type: ignore[attr-defined]
 
         # Check nested settings - should be dataclass
-        assert result.settings.theme == "dark"
+        assert result.settings.theme == "dark"  # type: ignore[attr-defined]
         # Note: When nested in BaseModel with extra='allow', Pydantic may preserve extra fields
         # even on dataclass children. The important thing is that settings is still a dataclass.
-        assert not issubclass(type(result.settings), BaseModel)
+        assert not issubclass(type(result.settings), BaseModel)  # type: ignore[attr-defined]
 
     def test_additional_properties_false_vs_missing(self):
         """Test difference between additionalProperties: false and missing additionalProperties"""
@@ -1511,9 +1511,9 @@ class TestAdditionalProperties:
 
         # Test with extra fields and defaults
         result = validator.validate_python({"extra": "field"})
-        assert result.name == "anonymous"
-        assert result.age == 0
-        assert result.extra == "field"
+        assert result.name == "anonymous"  # type: ignore[attr-defined]
+        assert result.age == 0  # type: ignore[attr-defined]
+        assert result.extra == "field"  # type: ignore[attr-defined]
 
     def test_additional_properties_type_consistency(self):
         """Test that the same schema always returns the same type"""
@@ -1570,7 +1570,7 @@ class TestFieldsWithDefaults:
         validator = TypeAdapter(generated_type)
         result = validator.validate_python({})
 
-        assert result.flag is False
+        assert result.flag is False  # type: ignore[attr-defined]
 
     def test_field_with_default_accepts_explicit_value(self):
         """Test that fields with defaults accept explicit values."""
@@ -1583,4 +1583,4 @@ class TestFieldsWithDefaults:
         validator = TypeAdapter(generated_type)
         result = validator.validate_python({"flag": True})
 
-        assert result.flag is True
+        assert result.flag is True  # type: ignore[attr-defined]