Merge branch 'main' into feat/docstring-param-descriptions

Author: ameenalkhaldi

CLAUDE.md

@@ -29,18 +29,31 @@ This document contains critical information about working with this codebase. Fo
    - IMPORTANT: The `tests/client/test_client.py` is the most well designed test file. Follow its patterns.
    - IMPORTANT: Be minimal, and focus on E2E tests: Use the `mcp.client.Client` whenever possible.
    - Coverage: CI requires 100% (`fail_under = 100`, `branch = true`).
-     - Full check: `./scripts/test` (~20s, matches CI exactly)
-     - Targeted check while iterating:
+     - Full check: `./scripts/test` (~23s). Runs coverage + `strict-no-cover` on the
+       default Python. Not identical to CI: CI also runs 3.10–3.14 × {ubuntu, windows},
+       and some branch-coverage quirks only surface on specific matrix entries.
+     - Targeted check while iterating (~4s, deterministic):
 
        ```bash
        uv run --frozen coverage erase
        uv run --frozen coverage run -m pytest tests/path/test_foo.py
        uv run --frozen coverage combine
        uv run --frozen coverage report --include='src/mcp/path/foo.py' --fail-under=0
+       UV_FROZEN=1 uv run --frozen strict-no-cover
        ```
 
        Partial runs can't hit 100% (coverage tracks `tests/` too), so `--fail-under=0`
-       and `--include` scope the report to what you actually changed.
+       and `--include` scope the report. `strict-no-cover` has no false positives on
+       partial runs — if your new test executes a line marked `# pragma: no cover`,
+       even a single-file run catches it.
+   - Coverage pragmas:
+     - `# pragma: no cover` — line is never executed. CI's `strict-no-cover` fails if
+       it IS executed. When your test starts covering such a line, remove the pragma.
+     - `# pragma: lax no cover` — excluded from coverage but not checked by
+       `strict-no-cover`. Use for lines covered on some platforms/versions but not
+       others.
+     - `# pragma: no branch` — excludes branch arcs only. coverage.py misreports the
+       `->exit` arc for nested `async with` on Python 3.11+ (worse on 3.14/Windows).
    - Avoid `anyio.sleep()` with a fixed duration to wait for async operations. Instead:
      - Use `anyio.Event` — set it in the callback/handler, `await event.wait()` in the test
      - For stream messages, use `await stream.receive()` instead of `sleep()` + `receive_nowait()`

docs/experimental/tasks-server.md

@@ -408,16 +408,10 @@ For custom error messages, call `task.fail()` before raising.
 For web applications, use the Streamable HTTP transport:
 
 ```python
-from collections.abc import AsyncIterator
-from contextlib import asynccontextmanager
-
 import uvicorn
-from starlette.applications import Starlette
-from starlette.routing import Mount
 
 from mcp.server import Server
 from mcp.server.experimental.task_context import ServerTaskContext
-from mcp.server.streamable_http_manager import StreamableHTTPSessionManager
 from mcp.types import (
     CallToolResult, CreateTaskResult, TextContent, Tool, ToolExecution, TASK_REQUIRED,
 )
@@ -462,22 +456,8 @@ async def handle_tool(name: str, arguments: dict) -> CallToolResult | CreateTask
     return CallToolResult(content=[TextContent(type="text", text=f"Unknown: {name}")], isError=True)
 
 
-def create_app():
-    session_manager = StreamableHTTPSessionManager(app=server)
-
-    @asynccontextmanager
-    async def lifespan(app: Starlette) -> AsyncIterator[None]:
-        async with session_manager.run():
-            yield
-
-    return Starlette(
-        routes=[Mount("/mcp", app=session_manager.handle_request)],
-        lifespan=lifespan,
-    )
-
-
 if __name__ == "__main__":
-    uvicorn.run(create_app(), host="127.0.0.1", port=8000)
+    uvicorn.run(server.streamable_http_app(), host="127.0.0.1", port=8000)
 ```
 
 ## Testing Task Servers

examples/servers/simple-pagination/README.md

@@ -4,14 +4,14 @@ A simple MCP server demonstrating pagination for tools, resources, and prompts u
 
 ## Usage
 
-Start the server using either stdio (default) or SSE transport:
+Start the server using either stdio (default) or Streamable HTTP transport:
 
 ```bash
 # Using stdio transport (default)
 uv run mcp-simple-pagination
 
-# Using SSE transport on custom port
-uv run mcp-simple-pagination --transport sse --port 8000
+# Using Streamable HTTP transport on custom port
+uv run mcp-simple-pagination --transport streamable-http --port 8000
 ```
 
 The server exposes:

examples/servers/simple-pagination/mcp_simple_pagination/server.py

@@ -10,7 +10,6 @@
 import click
 from mcp import types
 from mcp.server import Server, ServerRequestContext
-from starlette.requests import Request
 
 T = TypeVar("T")
 
@@ -143,10 +142,10 @@ async def handle_get_prompt(ctx: ServerRequestContext, params: types.GetPromptRe
 
 
 @click.command()
-@click.option("--port", default=8000, help="Port to listen on for SSE")
+@click.option("--port", default=8000, help="Port to listen on for HTTP")
 @click.option(
     "--transport",
-    type=click.Choice(["stdio", "sse"]),
+    type=click.Choice(["stdio", "streamable-http"]),
     default="stdio",
     help="Transport type",
 )
@@ -161,30 +160,10 @@ def main(port: int, transport: str) -> int:
         on_get_prompt=handle_get_prompt,
     )
 
-    if transport == "sse":
-        from mcp.server.sse import SseServerTransport
-        from starlette.applications import Starlette
-        from starlette.responses import Response
-        from starlette.routing import Mount, Route
-
-        sse = SseServerTransport("/messages/")
-
-        async def handle_sse(request: Request):
-            async with sse.connect_sse(request.scope, request.receive, request._send) as streams:  # type: ignore[reportPrivateUsage]
-                await app.run(streams[0], streams[1], app.create_initialization_options())
-            return Response()
-
-        starlette_app = Starlette(
-            debug=True,
-            routes=[
-                Route("/sse", endpoint=handle_sse, methods=["GET"]),
-                Mount("/messages/", app=sse.handle_post_message),
-            ],
-        )
-
+    if transport == "streamable-http":
         import uvicorn
 
-        uvicorn.run(starlette_app, host="127.0.0.1", port=port)
+        uvicorn.run(app.streamable_http_app(), host="127.0.0.1", port=port)
     else:
         from mcp.server.stdio import stdio_server
 

examples/servers/simple-prompt/README.md

@@ -4,14 +4,14 @@ A simple MCP server that exposes a customizable prompt template with optional co
 
 ## Usage
 
-Start the server using either stdio (default) or SSE transport:
+Start the server using either stdio (default) or Streamable HTTP transport:
 
 ```bash
 # Using stdio transport (default)
 uv run mcp-simple-prompt
 
-# Using SSE transport on custom port
-uv run mcp-simple-prompt --transport sse --port 8000
+# Using Streamable HTTP transport on custom port
+uv run mcp-simple-prompt --transport streamable-http --port 8000
 ```
 
 The server exposes a prompt named "simple" that accepts two optional arguments:

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

@@ -2,7 +2,6 @@
 import click
 from mcp import types
 from mcp.server import Server, ServerRequestContext
-from starlette.requests import Request
 
 
 def create_messages(context: str | None = None, topic: str | None = None) -> list[types.PromptMessage]:
@@ -69,10 +68,10 @@ async def handle_get_prompt(ctx: ServerRequestContext, params: types.GetPromptRe
 
 
 @click.command()
-@click.option("--port", default=8000, help="Port to listen on for SSE")
+@click.option("--port", default=8000, help="Port to listen on for HTTP")
 @click.option(
     "--transport",
-    type=click.Choice(["stdio", "sse"]),
+    type=click.Choice(["stdio", "streamable-http"]),
     default="stdio",
     help="Transport type",
 )
@@ -83,30 +82,10 @@ def main(port: int, transport: str) -> int:
         on_get_prompt=handle_get_prompt,
     )
 
-    if transport == "sse":
-        from mcp.server.sse import SseServerTransport
-        from starlette.applications import Starlette
-        from starlette.responses import Response
-        from starlette.routing import Mount, Route
-
-        sse = SseServerTransport("/messages/")
-
-        async def handle_sse(request: Request):
-            async with sse.connect_sse(request.scope, request.receive, request._send) as streams:  # type: ignore[reportPrivateUsage]
-                await app.run(streams[0], streams[1], app.create_initialization_options())
-            return Response()
-
-        starlette_app = Starlette(
-            debug=True,
-            routes=[
-                Route("/sse", endpoint=handle_sse),
-                Mount("/messages/", app=sse.handle_post_message),
-            ],
-        )
-
+    if transport == "streamable-http":
         import uvicorn
 
-        uvicorn.run(starlette_app, host="127.0.0.1", port=port)
+        uvicorn.run(app.streamable_http_app(), host="127.0.0.1", port=port)
     else:
         from mcp.server.stdio import stdio_server
 

examples/servers/simple-resource/README.md

@@ -4,14 +4,14 @@ A simple MCP server that exposes sample text files as resources.
 
 ## Usage
 
-Start the server using either stdio (default) or SSE transport:
+Start the server using either stdio (default) or Streamable HTTP transport:
 
 ```bash
 # Using stdio transport (default)
 uv run mcp-simple-resource
 
-# Using SSE transport on custom port
-uv run mcp-simple-resource --transport sse --port 8000
+# Using Streamable HTTP transport on custom port
+uv run mcp-simple-resource --transport streamable-http --port 8000
 ```
 
 The server exposes some basic text file resources that can be read by clients.

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

@@ -4,7 +4,6 @@
 import click
 from mcp import types
 from mcp.server import Server, ServerRequestContext
-from starlette.requests import Request
 
 SAMPLE_RESOURCES = {
     "greeting": {
@@ -62,10 +61,10 @@ async def handle_read_resource(
 
 
 @click.command()
-@click.option("--port", default=8000, help="Port to listen on for SSE")
+@click.option("--port", default=8000, help="Port to listen on for HTTP")
 @click.option(
     "--transport",
-    type=click.Choice(["stdio", "sse"]),
+    type=click.Choice(["stdio", "streamable-http"]),
     default="stdio",
     help="Transport type",
 )
@@ -76,30 +75,10 @@ def main(port: int, transport: str) -> int:
         on_read_resource=handle_read_resource,
     )
 
-    if transport == "sse":
-        from mcp.server.sse import SseServerTransport
-        from starlette.applications import Starlette
-        from starlette.responses import Response
-        from starlette.routing import Mount, Route
-
-        sse = SseServerTransport("/messages/")
-
-        async def handle_sse(request: Request):
-            async with sse.connect_sse(request.scope, request.receive, request._send) as streams:  # type: ignore[reportPrivateUsage]
-                await app.run(streams[0], streams[1], app.create_initialization_options())
-            return Response()
-
-        starlette_app = Starlette(
-            debug=True,
-            routes=[
-                Route("/sse", endpoint=handle_sse, methods=["GET"]),
-                Mount("/messages/", app=sse.handle_post_message),
-            ],
-        )
-
+    if transport == "streamable-http":
         import uvicorn
 
-        uvicorn.run(starlette_app, host="127.0.0.1", port=port)
+        uvicorn.run(app.streamable_http_app(), host="127.0.0.1", port=port)
     else:
         from mcp.server.stdio import stdio_server
 

examples/servers/simple-streamablehttp-stateless/README.md

@@ -7,7 +7,6 @@ A stateless MCP server example demonstrating the StreamableHttp transport withou
 - Uses the StreamableHTTP transport in stateless mode (mcp_session_id=None)
 - Each request creates a new ephemeral connection
 - No session state maintained between requests
-- Task lifecycle scoped to individual requests
 - Suitable for deployment in multi-node environments
 
 ## Usage

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

@@ -1,17 +1,11 @@
-import contextlib
 import logging
-from collections.abc import AsyncIterator
 
 import anyio
 import click
 import uvicorn
 from mcp import types
 from mcp.server import Server, ServerRequestContext
-from mcp.server.streamable_http_manager import StreamableHTTPSessionManager
-from starlette.applications import Starlette
 from starlette.middleware.cors import CORSMiddleware
-from starlette.routing import Mount
-from starlette.types import Receive, Scope, Send
 
 logger = logging.getLogger(__name__)
 
@@ -104,39 +98,17 @@ def main(
         on_call_tool=handle_call_tool,
     )
 
-    # Create the session manager with true stateless mode
-    session_manager = StreamableHTTPSessionManager(
-        app=app,
-        event_store=None,
+    starlette_app = app.streamable_http_app(
+        stateless_http=True,
         json_response=json_response,
-        stateless=True,
-    )
-
-    async def handle_streamable_http(scope: Scope, receive: Receive, send: Send) -> None:
-        await session_manager.handle_request(scope, receive, send)
-
-    @contextlib.asynccontextmanager
-    async def lifespan(app: Starlette) -> AsyncIterator[None]:
-        """Context manager for session manager."""
-        async with session_manager.run():
-            logger.info("Application started with StreamableHTTP session manager!")
-            try:
-                yield
-            finally:
-                logger.info("Application shutting down...")
-
-    # Create an ASGI application using the transport
-    starlette_app = Starlette(
         debug=True,
-        routes=[Mount("/mcp", app=handle_streamable_http)],
-        lifespan=lifespan,
     )
 
     # Wrap ASGI application with CORS middleware to expose Mcp-Session-Id header
     # for browser-based clients (ensures 500 errors get proper CORS headers)
     starlette_app = CORSMiddleware(
         starlette_app,
-        allow_origins=["*"],  # Allow all origins - adjust as needed for production
+        allow_origins=["*"],  # Note: streamable_http_app() enforces localhost-only Origin by default
         allow_methods=["GET", "POST", "DELETE"],  # MCP streamable HTTP methods
         expose_headers=["Mcp-Session-Id"],
     )