Merge branch 'main' into feat/sampling-resources

Author: LucaButBoring

examples/clients/simple-chatbot/mcp_simple_chatbot/main.py

@@ -245,7 +245,7 @@ def get_response(self, messages: list[dict[str, str]]) -> str:
         }
         payload = {
             "messages": messages,
-            "model": "llama-3.2-90b-vision-preview",
+            "model": "meta-llama/llama-4-scout-17b-16e-instruct",
             "temperature": 0.7,
             "max_tokens": 4096,
             "top_p": 1,
@@ -284,12 +284,9 @@ def __init__(self, servers: list[Server], llm_client: LLMClient) -> None:
 
     async def cleanup_servers(self) -> None:
         """Clean up all servers properly."""
-        cleanup_tasks = [
-            asyncio.create_task(server.cleanup()) for server in self.servers
-        ]
-        if cleanup_tasks:
+        for server in reversed(self.servers):
             try:
-                await asyncio.gather(*cleanup_tasks, return_exceptions=True)
+                await server.cleanup()
             except Exception as e:
                 logging.warning(f"Warning during final cleanup: {e}")
 

pyproject.toml

@@ -109,7 +109,13 @@ members = ["examples/servers/*"]
 mcp = { workspace = true }
 
 [tool.pytest.ini_options]
+log_cli = true
 xfail_strict = true
+addopts = """
+    --color=yes
+    --capture=fd
+    --numprocesses auto
+"""
 filterwarnings = [
     "error",
     # This should be fixed on Uvicorn's side.

src/mcp/client/session.py

@@ -209,7 +209,9 @@ async def list_resources(
             types.ClientRequest(
                 types.ListResourcesRequest(
                     method="resources/list",
-                    cursor=cursor,
+                    params=types.PaginatedRequestParams(cursor=cursor)
+                    if cursor is not None
+                    else None,
                 )
             ),
             types.ListResourcesResult,
@@ -223,7 +225,9 @@ async def list_resource_templates(
             types.ClientRequest(
                 types.ListResourceTemplatesRequest(
                     method="resources/templates/list",
-                    cursor=cursor,
+                    params=types.PaginatedRequestParams(cursor=cursor)
+                    if cursor is not None
+                    else None,
                 )
             ),
             types.ListResourceTemplatesResult,
@@ -295,7 +299,9 @@ async def list_prompts(self, cursor: str | None = None) -> types.ListPromptsResu
             types.ClientRequest(
                 types.ListPromptsRequest(
                     method="prompts/list",
-                    cursor=cursor,
+                    params=types.PaginatedRequestParams(cursor=cursor)
+                    if cursor is not None
+                    else None,
                 )
             ),
             types.ListPromptsResult,
@@ -340,7 +346,9 @@ async def list_tools(self, cursor: str | None = None) -> types.ListToolsResult:
             types.ClientRequest(
                 types.ListToolsRequest(
                     method="tools/list",
-                    cursor=cursor,
+                    params=types.PaginatedRequestParams(cursor=cursor)
+                    if cursor is not None
+                    else None,
                 )
             ),
             types.ListToolsResult,

src/mcp/client/session_group.py

@@ -77,10 +77,10 @@ class ClientSessionGroup:
     the client and can be accessed via the session.
 
     Example Usage:
-        name_fn = lambda name, server_info: f"{(server_info.name)}-{name}"
+        name_fn = lambda name, server_info: f"{(server_info.name)}_{name}"
         async with ClientSessionGroup(component_name_hook=name_fn) as group:
             for server_params in server_params:
-                group.connect_to_server(server_param)
+                await group.connect_to_server(server_param)
             ...
 
     """
@@ -145,14 +145,15 @@ async def __aexit__(
     ) -> bool | None:
         """Closes session exit stacks and main exit stack upon completion."""
 
+        # Only close the main exit stack if we created it
+        if self._owns_exit_stack:
+            await self._exit_stack.aclose()
+
         # Concurrently close session stacks.
         async with anyio.create_task_group() as tg:
             for exit_stack in self._session_exit_stacks.values():
                 tg.start_soon(exit_stack.aclose)
 
-        # Only close the main exit stack if we created it
-        if self._owns_exit_stack:
-            await self._exit_stack.aclose()
 
     @property
     def sessions(self) -> list[mcp.ClientSession]:

src/mcp/client/sse.py

@@ -10,7 +10,7 @@
 from httpx_sse import aconnect_sse
 
 import mcp.types as types
-from mcp.shared._httpx_utils import create_mcp_http_client
+from mcp.shared._httpx_utils import McpHttpClientFactory, create_mcp_http_client
 from mcp.shared.message import SessionMessage
 
 logger = logging.getLogger(__name__)
@@ -26,6 +26,7 @@ async def sse_client(
     headers: dict[str, Any] | None = None,
     timeout: float = 5,
     sse_read_timeout: float = 60 * 5,
+    httpx_client_factory: McpHttpClientFactory = create_mcp_http_client,
     auth: httpx.Auth | None = None,
 ):
     """
@@ -53,7 +54,7 @@ async def sse_client(
     async with anyio.create_task_group() as tg:
         try:
             logger.info(f"Connecting to SSE endpoint: {remove_request_params(url)}")
-            async with create_mcp_http_client(headers=headers, auth=auth) as client:
+            async with httpx_client_factory(headers=headers, auth=auth) as client:
                 async with aconnect_sse(
                     client,
                     "GET",

src/mcp/client/streamable_http.py

@@ -19,7 +19,7 @@
 from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
 from httpx_sse import EventSource, ServerSentEvent, aconnect_sse
 
-from mcp.shared._httpx_utils import create_mcp_http_client
+from mcp.shared._httpx_utils import McpHttpClientFactory, create_mcp_http_client
 from mcp.shared.message import ClientMessageMetadata, SessionMessage
 from mcp.types import (
     ErrorData,
@@ -430,6 +430,7 @@ async def streamablehttp_client(
     timeout: timedelta = timedelta(seconds=30),
     sse_read_timeout: timedelta = timedelta(seconds=60 * 5),
     terminate_on_close: bool = True,
+    httpx_client_factory: McpHttpClientFactory = create_mcp_http_client,
     auth: httpx.Auth | None = None,
 ) -> AsyncGenerator[
     tuple[
@@ -464,7 +465,7 @@ async def streamablehttp_client(
         try:
             logger.info(f"Connecting to StreamableHTTP endpoint: {url}")
 
-            async with create_mcp_http_client(
+            async with httpx_client_factory(
                 headers=transport.request_headers,
                 timeout=httpx.Timeout(
                     transport.timeout.seconds, read=transport.sse_read_timeout.seconds

src/mcp/server/fastmcp/tools/base.py

@@ -1,5 +1,6 @@
 from __future__ import annotations as _annotations
 
+import functools
 import inspect
 from collections.abc import Callable
 from typing import TYPE_CHECKING, Any, get_origin
@@ -53,7 +54,7 @@ def from_function(
             raise ValueError("You must provide a name for lambda functions")
 
         func_doc = description or fn.__doc__ or ""
-        is_async = inspect.iscoroutinefunction(fn)
+        is_async = _is_async_callable(fn)
 
         if context_kwarg is None:
             sig = inspect.signature(fn)
@@ -98,3 +99,12 @@ async def run(
             )
         except Exception as e:
             raise ToolError(f"Error executing tool {self.name}: {e}") from e
+
+
+def _is_async_callable(obj: Any) -> bool:
+    while isinstance(obj, functools.partial):
+        obj = obj.func
+
+    return inspect.iscoroutinefunction(obj) or (
+        callable(obj) and inspect.iscoroutinefunction(getattr(obj, "__call__", None))
+    )

src/mcp/shared/_httpx_utils.py

@@ -1,12 +1,21 @@
 """Utilities for creating standardized httpx AsyncClient instances."""
 
-from typing import Any
+from typing import Any, Protocol
 
 import httpx
 
 __all__ = ["create_mcp_http_client"]
 
 
+class McpHttpClientFactory(Protocol):
+    def __call__(
+        self,
+        headers: dict[str, str] | None = None,
+        timeout: httpx.Timeout | None = None,
+        auth: httpx.Auth | None = None,
+    ) -> httpx.AsyncClient: ...
+
+
 def create_mcp_http_client(
     headers: dict[str, str] | None = None,
     timeout: httpx.Timeout | None = None,

src/mcp/types.py

@@ -53,6 +53,14 @@ class Meta(BaseModel):
     meta: Meta | None = Field(alias="_meta", default=None)
 
 
+class PaginatedRequestParams(RequestParams):
+    cursor: Cursor | None = None
+    """
+    An opaque token representing the current pagination position.
+    If provided, the server should return results starting after this cursor.
+    """
+
+
 class NotificationParams(BaseModel):
     class Meta(BaseModel):
         model_config = ConfigDict(extra="allow")
@@ -79,12 +87,13 @@ class Request(BaseModel, Generic[RequestParamsT, MethodT]):
     model_config = ConfigDict(extra="allow")
 
 
-class PaginatedRequest(Request[RequestParamsT, MethodT]):
-    cursor: Cursor | None = None
-    """
-    An opaque token representing the current pagination position.
-    If provided, the server should return results starting after this cursor.
-    """
+class PaginatedRequest(
+    Request[PaginatedRequestParams | None, MethodT], Generic[MethodT]
+):
+    """Base class for paginated requests,
+    matching the schema's PaginatedRequest interface."""
+
+    params: PaginatedRequestParams | None = None
 
 
 class Notification(BaseModel, Generic[NotificationParamsT, MethodT]):
@@ -358,13 +367,10 @@ class ProgressNotification(
     params: ProgressNotificationParams
 
 
-class ListResourcesRequest(
-    PaginatedRequest[RequestParams | None, Literal["resources/list"]]
-):
+class ListResourcesRequest(PaginatedRequest[Literal["resources/list"]]):
     """Sent from the client to request a list of resources the server has."""
 
     method: Literal["resources/list"]
-    params: RequestParams | None = None
 
 
 class Annotations(BaseModel):
@@ -423,12 +429,11 @@ class ListResourcesResult(PaginatedResult):
 
 
 class ListResourceTemplatesRequest(
-    PaginatedRequest[RequestParams | None, Literal["resources/templates/list"]]
+    PaginatedRequest[Literal["resources/templates/list"]]
 ):
     """Sent from the client to request a list of resource templates the server has."""
 
     method: Literal["resources/templates/list"]
-    params: RequestParams | None = None
 
 
 class ListResourceTemplatesResult(PaginatedResult):
@@ -570,13 +575,10 @@ class ResourceUpdatedNotification(
     params: ResourceUpdatedNotificationParams
 
 
-class ListPromptsRequest(
-    PaginatedRequest[RequestParams | None, Literal["prompts/list"]]
-):
+class ListPromptsRequest(PaginatedRequest[Literal["prompts/list"]]):
     """Sent from the client to request a list of prompts and prompt templates."""
 
     method: Literal["prompts/list"]
-    params: RequestParams | None = None
 
 
 class PromptArgument(BaseModel):
@@ -703,11 +705,10 @@ class PromptListChangedNotification(
     params: NotificationParams | None = None
 
 
-class ListToolsRequest(PaginatedRequest[RequestParams | None, Literal["tools/list"]]):
+class ListToolsRequest(PaginatedRequest[Literal["tools/list"]]):
     """Sent from the client to request a list of tools the server has."""
 
     method: Literal["tools/list"]
-    params: RequestParams | None = None
 
 
 class ToolAnnotations(BaseModel):
@@ -741,7 +742,7 @@ class ToolAnnotations(BaseModel):
 
     idempotentHint: bool | None = None
     """
-    If true, calling the tool repeatedly with the same arguments 
+    If true, calling the tool repeatedly with the same arguments
     will have no additional effect on the its environment.
     (This property is meaningful only when `readOnlyHint == false`)
     Default: false