fastmcp-slim

The dependency-slim FastMCP package.

fastmcp-slim Permissive license Apache-2.0 Active ★ 27,204 v3.4.7 released 2026-08-10

Install

fastmcp-slim on PyPI

pip

pip install fastmcp-slim

uv

uv add fastmcp-slim

poetry

poetry add fastmcp-slim

Package facts

License	Apache-2.0 (permissive)
Python support	supports the current Python release (>=3.10)
Install friction	low — pure-Python wheel
Runtime dependencies	6 — platformdirs, pydantic-settings, pydantic, python-dotenv, rich, typing-extensions
Maintenance	actively maintained — 3 days since the last release
Last repo commit	2026-08-13
First released	2026-05-11
Popularity	one of the top 1,000 most-downloaded packages on PyPI (30-day window, as of 2026-08-13)
Known vulnerabilities	none known (OSV.dev, checked 2026-08-13)

Evidence: fastmcp_slim-3.4.7-py3-none-any.whl

Keywords: agent, fastmcp, llm, mcp, mcp client, mcp server, model context protocol

Intended Audience :: DevelopersLicense :: OSI Approved :: Apache Software LicenseProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Topic :: Scientific/Engineering :: Artificial IntelligenceTyping :: Typed

About fastmcp-slim

from the package's own PyPI description — quoted content, verbatim

FastMCP 🚀

<strong>Move fast and make things.</strong>

Made with 💙 by Prefect

Docs (image) Discord (image) [![PyPI -...

Read as markdown · JSON record · Source repository · Homepage · Docs

AI interpretation — verify before relying

AI-generated interpretation of the package facts above; every digit, version, license, or vulnerability id it cites is grounded in the facts already shown on this page

FastMCP-slim is a framework for building Model Context Protocol (MCP) servers that expose Python functions as tools, resources, and prompts to LLMs, with automatic schema generation and validation.

Low friction installation with six lightweight runtime dependencies and a pure-Python wheel. Actively maintained with a release 3 days old and strong community adoption.

Apache-2.0 permissive license allows free use, modification, and distribution in commercial and private projects with minimal restrictions beyond attribution and liability disclaimers.

Usage

pip install fastmcp-slim

from fastmcp import FastMCP

mcp = FastMCP("Demo")

@mcp.tool
def add(a: int, b: int) -> int:
    """Add two numbers"""
    return a + b

if __name__ == "__main__":
    mcp.run()

Requires Python 3.10 or later.

Verdict: FastMCP-slim is actively maintained with no known vulnerabilities, permissive Apache-2.0 licensing, and low install friction. It is production-ready for building MCP servers and clients that integrate Python functions with LLMs.

Needs verification

Whether fastmcp-slim is a feature-complete variant or a reduced-dependency version compared to the full fastmcp package
Performance characteristics and any runtime overhead compared to direct MCP protocol implementations
Community adoption scale and production deployment prevalence

model context protocol server frameworkllm tool exposure frameworkmcp server builderpython function to llm toolsmcp client and serverai agent tool protocolllm integration framework