modelcontextprotocol · maxisbey · Aug 16, 2026
diff --git a/src/mcp/shared/jsonrpc_dispatcher.py b/src/mcp/shared/jsonrpc_dispatcher.py
@@ -9,7 +9,7 @@
 
 import contextvars
 import logging
-from collections.abc import Awaitable, Callable, Mapping
+from collections.abc import Awaitable, Callable, Coroutine, Mapping
 from dataclasses import dataclass, field
 from functools import partial
 from typing import Any, Generic, Literal, cast
@@ -209,7 +209,9 @@ async def _wrapped(progress: float, total: float | None, message: str | None) ->
     return _wrapped
 
 
-def _contained_notify(fn: OnNotify) -> OnNotify:
+def _contained_notify(
+    fn: OnNotify,
+) -> Callable[[DispatchContext[TransportContext], str, Mapping[str, Any] | None], Coroutine[Any, Any, None]]:
     """Wrap a notification handler so it can't crash the dispatcher (same boundary as `_shielded_progress`)."""
 
     async def _wrapped(dctx: DispatchContext[TransportContext], method: str, params: Mapping[str, Any] | None) -> None:
@@ -670,7 +672,7 @@ def _resolve_pending(self, request_id: RequestId | None, outcome: dict[str, Any]
 
     def _spawn(
         self,
-        fn: Callable[..., Awaitable[Any]],
+        fn: Callable[..., Coroutine[Any, Any, Any]],
         *args: object,
         sender_ctx: contextvars.Context | None,
     ) -> None:

diff --git a/tests/client/test_stdio.py b/tests/client/test_stdio.py
@@ -436,7 +436,10 @@ async def die_late() -> None:
                     process.exit(0)
 
                 # The grace wait starts when stdin closes; anchor the death there.
-                process.on_stdin_close = lambda: tg.start_soon(die_late)
+                def schedule_death() -> None:
+                    tg.start_soon(die_late)
+
+                process.on_stdin_close = schedule_death
                 # no branch: the tracer drops this nested async-with's arcs under
                 # trio's MockClock even though the body runs.
                 async with stdio_client(FAKE_PARAMS):  # pragma: no branch

diff --git a/tests/shared/test_streamable_http.py b/tests/shared/test_streamable_http.py
@@ -1314,17 +1314,20 @@ async def _handle_context_list_tools(
 
 async def _handle_context_call_tool(ctx: ServerRequestContext, params: CallToolRequestParams) -> CallToolResult:
     assert params.name in ("echo_headers", "echo_context")
-    assert isinstance(ctx.request, Request)
+    assert ctx.request is not None
+    # Starlette's Request is generic over its state type (0.52+); pin the parameter so member access stays typed.
+    request: Request[Any] = ctx.request
+    assert isinstance(request, Request)
 
     if params.name == "echo_headers":
-        return CallToolResult(content=[TextContent(type="text", text=json.dumps(dict(ctx.request.headers)))])
+        return CallToolResult(content=[TextContent(type="text", text=json.dumps(dict(request.headers)))])
 
     assert params.arguments is not None
     context_data: dict[str, Any] = {
         "request_id": params.arguments.get("request_id"),
-        "headers": dict(ctx.request.headers),
-        "method": ctx.request.method,
-        "path": ctx.request.url.path,
+        "headers": dict(request.headers),
+        "method": request.method,
+        "path": request.url.path,
         "protocol_version": ctx.protocol_version,
         "session_protocol_version": ctx.session.protocol_version,
     }