mrlesmithjr-mcp-common

Shared building blocks for FastMCP servers: stderr-safe logging, layered configuration, XDG path resolution, and a consistent JSON error envelope. It is the common foundation under the mrlesmithjr/mcp tool suite, but has no dependency on those tools and is usable in any MCP server.

Import as mcp_common.

Install

pip install mrlesmithjr-mcp-common
# or
uv add mrlesmithjr-mcp-common

Usage

import json
from mcp_common.server import build_server, run_stdio
from mcp_common.errors import safe_tool

mcp = build_server("my-tool", instructions="What this server does.")

@mcp.tool()
@safe_tool
def do_thing(x: str) -> str:
    return json.dumps({"status": "ok", "data": x})

def main() -> None:
    run_stdio(mcp)

safe_tool wraps a tool so unhandled exceptions return a structured {"error": ...} envelope instead of crashing the server. build_server and run_stdio handle FastMCP setup and stdio transport; configure_logging() forces logs to stderr (stdout is reserved for the protocol).

Modules

Requirements

• Python 3.11+

License

MIT. Part of the mrlesmithjr/mcp workspace.