Merge branch 'modelcontextprotocol:main' into feature/add-enable-disable-methods-tools

Author: davila7

README.md

@@ -416,6 +416,9 @@ mcp = FastMCP("StatefulServer")
 # Stateless server (no session persistence)
 mcp = FastMCP("StatelessServer", stateless_http=True)
 
+# Stateless server (no session persistence, no sse stream with supported client)
+mcp = FastMCP("StatelessServer", stateless_http=True, json_response=True)
+
 # Run server with streamable_http transport
 mcp.run(transport="streamable-http")
 ```
@@ -448,15 +451,22 @@ def add_two(n: int) -> int:
 
 ```python
 # main.py
+import contextlib
 from fastapi import FastAPI
 from mcp.echo import echo
 from mcp.math import math
 
 
-app = FastAPI()
+# Create a combined lifespan to manage both session managers
+@contextlib.asynccontextmanager
+async def lifespan(app: FastAPI):
+    async with contextlib.AsyncExitStack() as stack:
+        await stack.enter_async_context(echo.mcp.session_manager.run())
+        await stack.enter_async_context(math.mcp.session_manager.run())
+        yield
+
 
-# Use the session manager's lifespan
-app = FastAPI(lifespan=lambda app: echo.mcp.session_manager.run())
+app = FastAPI(lifespan=lifespan)
 app.mount("/echo", echo.mcp.streamable_http_app())
 app.mount("/math", math.mcp.streamable_http_app())
 ```

examples/servers/simple-auth/mcp_simple_auth/__main__.py

@@ -4,4 +4,4 @@
 
 from mcp_simple_auth.server import main
 
-sys.exit(main())
+sys.exit(main())  # type: ignore[call-arg]

examples/servers/simple-prompt/mcp_simple_prompt/__main__.py

@@ -2,4 +2,4 @@
 
 from .server import main
 
-sys.exit(main())
+sys.exit(main())  # type: ignore[call-arg]

examples/servers/simple-resource/mcp_simple_resource/__main__.py

@@ -2,4 +2,4 @@
 
 from .server import main
 
-sys.exit(main())
+sys.exit(main())  # type: ignore[call-arg]

examples/servers/simple-resource/mcp_simple_resource/server.py

@@ -2,7 +2,7 @@
 import click
 import mcp.types as types
 from mcp.server.lowlevel import Server
-from pydantic import FileUrl
+from pydantic import AnyUrl
 
 SAMPLE_RESOURCES = {
     "greeting": "Hello! This is a sample text resource.",
@@ -26,7 +26,7 @@ def main(port: int, transport: str) -> int:
     async def list_resources() -> list[types.Resource]:
         return [
             types.Resource(
-                uri=FileUrl(f"file:///{name}.txt"),
+                uri=AnyUrl(f"file:///{name}.txt"),
                 name=name,
                 description=f"A sample text resource named {name}",
                 mimeType="text/plain",
@@ -35,7 +35,9 @@ async def list_resources() -> list[types.Resource]:
         ]
 
     @app.read_resource()
-    async def read_resource(uri: FileUrl) -> str | bytes:
+    async def read_resource(uri: AnyUrl) -> str | bytes:
+        if uri.path is None:
+            raise ValueError(f"Invalid resource path: {uri}")
         name = uri.path.replace(".txt", "").lstrip("/")
 
         if name not in SAMPLE_RESOURCES:

examples/servers/simple-streamablehttp-stateless/mcp_simple_streamablehttp_stateless/__main__.py

@@ -1,4 +1,7 @@
 from .server import main
 
 if __name__ == "__main__":
-    main()
+    # Click will handle CLI arguments
+    import sys
+
+    sys.exit(main())  # type: ignore[call-arg]

examples/servers/simple-streamablehttp/mcp_simple_streamablehttp/__main__.py

@@ -1,4 +1,4 @@
 from .server import main
 
 if __name__ == "__main__":
-    main()
+    main()  # type: ignore[call-arg]

examples/servers/simple-tool/mcp_simple_tool/__main__.py

@@ -2,4 +2,4 @@
 
 from .server import main
 
-sys.exit(main())
+sys.exit(main())  # type: ignore[call-arg]

pyproject.toml

@@ -85,7 +85,7 @@ Issues = "https://github.com/modelcontextprotocol/python-sdk/issues"
 packages = ["src/mcp"]
 
 [tool.pyright]
-include = ["src/mcp", "tests"]
+include = ["src/mcp", "tests", "examples/servers"]
 venvPath = "."
 venv = ".venv"
 strict = ["src/mcp/**/*.py"]

src/mcp/client/session.py

@@ -8,7 +8,7 @@
 import mcp.types as types
 from mcp.shared.context import RequestContext
 from mcp.shared.message import SessionMessage
-from mcp.shared.session import BaseSession, RequestResponder
+from mcp.shared.session import BaseSession, ProgressFnT, RequestResponder
 from mcp.shared.version import SUPPORTED_PROTOCOL_VERSIONS
 
 DEFAULT_CLIENT_INFO = types.Implementation(name="mcp", version="0.1.0")
@@ -201,23 +201,29 @@ async def set_logging_level(self, level: types.LoggingLevel) -> types.EmptyResul
             types.EmptyResult,
         )
 
-    async def list_resources(self) -> types.ListResourcesResult:
+    async def list_resources(
+        self, cursor: str | None = None
+    ) -> types.ListResourcesResult:
         """Send a resources/list request."""
         return await self.send_request(
             types.ClientRequest(
                 types.ListResourcesRequest(
                     method="resources/list",
+                    cursor=cursor,
                 )
             ),
             types.ListResourcesResult,
         )
 
-    async def list_resource_templates(self) -> types.ListResourceTemplatesResult:
+    async def list_resource_templates(
+        self, cursor: str | None = None
+    ) -> types.ListResourceTemplatesResult:
         """Send a resources/templates/list request."""
         return await self.send_request(
             types.ClientRequest(
                 types.ListResourceTemplatesRequest(
                     method="resources/templates/list",
+                    cursor=cursor,
                 )
             ),
             types.ListResourceTemplatesResult,
@@ -264,26 +270,32 @@ async def call_tool(
         name: str,
         arguments: dict[str, Any] | None = None,
         read_timeout_seconds: timedelta | None = None,
+        progress_callback: ProgressFnT | None = None,
     ) -> types.CallToolResult:
-        """Send a tools/call request."""
+        """Send a tools/call request with optional progress callback support."""
 
         return await self.send_request(
             types.ClientRequest(
                 types.CallToolRequest(
                     method="tools/call",
-                    params=types.CallToolRequestParams(name=name, arguments=arguments),
+                    params=types.CallToolRequestParams(
+                        name=name,
+                        arguments=arguments,
+                    ),
                 )
             ),
             types.CallToolResult,
             request_read_timeout_seconds=read_timeout_seconds,
+            progress_callback=progress_callback,
         )
 
-    async def list_prompts(self) -> types.ListPromptsResult:
+    async def list_prompts(self, cursor: str | None = None) -> types.ListPromptsResult:
         """Send a prompts/list request."""
         return await self.send_request(
             types.ClientRequest(
                 types.ListPromptsRequest(
                     method="prompts/list",
+                    cursor=cursor,
                 )
             ),
             types.ListPromptsResult,
@@ -322,12 +334,13 @@ async def complete(
             types.CompleteResult,
         )
 
-    async def list_tools(self) -> types.ListToolsResult:
+    async def list_tools(self, cursor: str | None = None) -> types.ListToolsResult:
         """Send a tools/list request."""
         return await self.send_request(
             types.ClientRequest(
                 types.ListToolsRequest(
                     method="tools/list",
+                    cursor=cursor,
                 )
             ),
             types.ListToolsResult,

src/mcp/server/fastmcp/resources/types.py

@@ -11,7 +11,7 @@
 import httpx
 import pydantic
 import pydantic_core
-from pydantic import Field, ValidationInfo
+from pydantic import AnyUrl, Field, ValidationInfo, validate_call
 
 from mcp.server.fastmcp.resources.base import Resource
 
@@ -68,6 +68,31 @@ async def read(self) -> str | bytes:
         except Exception as e:
             raise ValueError(f"Error reading resource {self.uri}: {e}")
 
+    @classmethod
+    def from_function(
+        cls,
+        fn: Callable[..., Any],
+        uri: str,
+        name: str | None = None,
+        description: str | None = None,
+        mime_type: str | None = None,
+    ) -> "FunctionResource":
+        """Create a FunctionResource from a function."""
+        func_name = name or fn.__name__
+        if func_name == "<lambda>":
+            raise ValueError("You must provide a name for lambda functions")
+
+        # ensure the arguments are properly cast
+        fn = validate_call(fn)
+
+        return cls(
+            uri=AnyUrl(uri),
+            name=func_name,
+            description=description or fn.__doc__ or "",
+            mime_type=mime_type or "text/plain",
+            fn=fn,
+        )
+
 
 class FileResource(Resource):
     """A resource that reads from a file.

src/mcp/server/fastmcp/server.py

@@ -148,9 +148,11 @@ def __init__(
         self._mcp_server = MCPServer(
             name=name or "FastMCP",
             instructions=instructions,
-            lifespan=lifespan_wrapper(self, self.settings.lifespan)
-            if self.settings.lifespan
-            else default_lifespan,
+            lifespan=(
+                lifespan_wrapper(self, self.settings.lifespan)
+                if self.settings.lifespan
+                else default_lifespan
+            ),
         )
         self._tool_manager = ToolManager(
             warn_on_duplicate_tools=self.settings.warn_on_duplicate_tools
@@ -465,16 +467,16 @@ def decorator(fn: AnyFunction) -> AnyFunction:
                     uri_template=uri,
                     name=name,
                     description=description,
-                    mime_type=mime_type or "text/plain",
+                    mime_type=mime_type,
                 )
             else:
                 # Register as regular resource
-                resource = FunctionResource(
-                    uri=AnyUrl(uri),
+                resource = FunctionResource.from_function(
+                    fn=fn,
+                    uri=uri,
                     name=name,
                     description=description,
-                    mime_type=mime_type or "text/plain",
-                    fn=fn,
+                    mime_type=mime_type,
                 )
                 self.add_resource(resource)
             return fn
@@ -961,7 +963,6 @@ async def report_progress(
             total: Optional total value e.g. 100
             message: Optional message e.g. Starting render...
         """
-
         progress_token = (
             self.request_context.meta.progressToken
             if self.request_context.meta

src/mcp/server/session.py

@@ -52,6 +52,7 @@ async def handle_list_prompts(ctx: RequestContext) -> list[types.Prompt]:
     BaseSession,
     RequestResponder,
 )
+from mcp.shared.version import SUPPORTED_PROTOCOL_VERSIONS
 
 
 class InitializationState(Enum):
@@ -150,13 +151,16 @@ async def _received_request(
     ):
         match responder.request.root:
             case types.InitializeRequest(params=params):
+                requested_version = params.protocolVersion
                 self._initialization_state = InitializationState.Initializing
                 self._client_params = params
                 with responder:
                     await responder.respond(
                         types.ServerResult(
                             types.InitializeResult(
-                                protocolVersion=types.LATEST_PROTOCOL_VERSION,
+                                protocolVersion=requested_version
+                                if requested_version in SUPPORTED_PROTOCOL_VERSIONS
+                                else types.LATEST_PROTOCOL_VERSION,
                                 capabilities=self._init_options.capabilities,
                                 serverInfo=types.Implementation(
                                     name=self._init_options.server_name,