Max Isbey
98bd125ddd
The 2026-07-28 protocol did not work over stdio: subscriptions/listen was hard-refused, a legacy initialize arriving during an in-flight modern request was accepted and re-locked the connection, and a peer cancel produced a trailing "Request cancelled" frame. All three share one root cause: the connection's era was derived from which requests had completed instead of being decided once, in wire order, from how the client opened the connection. Replace serve_dual_era_loop and serve_loop with a single serve_stream driver that decides the era synchronously in the dispatcher's read loop, before the request body is spawned. initialize (or any envelope-less request) opens the legacy era, an enveloped request opens the modern era, server/discover is answered without pinning, and a stray leading notification opens nothing. A conflicting era claim on a committed connection is refused (-32022 or -32600) rather than silently switching. Cancel silence is structural: each request answers through a one-shot channel whose write target becomes a powerless void on a peer cancel, so there is no cancelled-check at any write site. The generic JSON-RPC dispatcher loses the code-0 cancel frame, the code-0 str(exc) catch-all, and the inline_methods knob, and documents that handlers are invoked synchronously in receive order with the returned awaitable as the body. Add a Posture enum (DUAL default, LEGACY_ONLY, MODERN_ONLY) on the Server and MCPServer constructors, honoured by the stream driver and the streamable-HTTP manager alike. Server.run(read, write) now stands alone, Server.lifespan() is a bound context manager, and serve_listener / newline_json_transport / close_subscriptions() give a straightforward path for custom transports. See docs/migration.md for the full list of observable changes.
MCP Everything Server
A comprehensive MCP server implementing all protocol features for conformance testing.
Overview
The Everything Server is a reference implementation that demonstrates all features of the Model Context Protocol (MCP). It is designed to be used with the MCP Conformance Test Framework to validate MCP client and server implementations.
Installation
From the python-sdk root directory:
uv sync --frozen
Usage
Running the Server
Start the server with default settings (port 3001):
uv run -m mcp_everything_server
Or with custom options:
uv run -m mcp_everything_server --port 3001 --log-level DEBUG
The server will be available at: http://localhost:3001/mcp
Command-Line Options
--port- Port to listen on (default: 3001)--log-level- Logging level: DEBUG, INFO, WARNING, ERROR, CRITICAL (default: INFO)
Running Conformance Tests
See the MCP Conformance Test Framework for instructions on running conformance tests against this server.