🚀 The fast, Pythonic way to build MCP servers and clients. https://gofastmcp.com
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Jeremiah Lowin 32f1118a11
Expose minimum_check_interval, reduce task pickup latency (#3500)
* perf: expose minimum_check_interval, reduce task pickup latency

The Docket Worker polls for new tasks every minimum_check_interval
(previously hardcoded to 250ms in pydocket). Expose this setting so
users can tune it, default to 50ms, and override to 10ms in tests.

This cuts average task pickup latency from ~125ms to ~5ms per task.

* perf: reduce task test overhead and eliminate cross-test contamination

- Expose minimum_check_interval setting (default 50ms, 10ms in tests)
  to reduce Docket Worker task pickup latency
- Isolate fakeredis per test via unique memory:// URLs to prevent
  stale _async_blocking tasks from contaminating subsequent tests
- Make client disconnect timeout configurable (default 5s, 1s in tests)
- Add --durations=50 to CI for passive performance regression detection
- Remove 15s timeout band-aids from task test conftest files
- Add explicit @pytest.mark.timeout(10) to cancellation tests
- Fix deprecated FastMCP.as_proxy() usage in test_task_proxy.py
2026-03-14 16:08:28 -04:00
.claude Add dependency version compatibility guidance to code-review skill 2026-03-13 17:24:53 -05:00
.cursor/rules Add agent skills for testing and code review (#2846) 2026-01-12 11:24:39 -05:00
.github Expose minimum_check_interval, reduce task pickup latency (#3500) 2026-03-14 16:08:28 -04:00
docs Add fastmcp dev apps command with browser UI preview (#3489) 2026-03-14 12:29:37 -04:00
examples Add fastmcp dev apps command with browser UI preview (#3489) 2026-03-14 12:29:37 -04:00
scripts Fix auto-close MRE script posting comment without closing (#3386) 2026-03-04 16:56:29 -05:00
skills/fastmcp-client-cli Add fastmcp discover and name-based server resolution (#3055) 2026-02-01 21:27:22 -05:00
src/fastmcp Expose minimum_check_interval, reduce task pickup latency (#3500) 2026-03-14 16:08:28 -04:00
tests Expose minimum_check_interval, reduce task pickup latency (#3500) 2026-03-14 16:08:28 -04:00
v3-notes docs: fix stale get_* references, now list_* (#3168) 2026-02-12 13:45:49 -06:00
.ccignore Update .ccignore 2025-06-30 18:41:04 -04:00
.coderabbit.yaml Exclude auto-generated python-sdk docs from CodeRabbit reviews (#3206) 2026-02-17 18:28:20 -05:00
.gitignore Add JWT audience validation and RFC 8707 warnings to auth providers (#3204) 2026-02-17 18:16:05 -05:00
.pre-commit-config.yaml Add loq file size limits and clean up type ignores (#2859) 2026-01-13 07:29:12 -05:00
.python-version Initial commit 2024-11-29 16:42:40 -05:00
AGENTS.md reverse CLAUDE.md/AGENTS.md symlink direction (#3294) 2026-02-25 11:18:59 -05:00
CLAUDE.md Add settings and environment variables reference (#3384) 2026-03-04 15:29:31 -05:00
CODE_OF_CONDUCT.md Create CODE_OF_CONDUCT.md (#1523) 2025-08-16 16:28:15 -04:00
justfile Split transports.py into modular structure (#2921) 2026-01-18 22:11:25 -05:00
LICENSE Basic cleanup 2025-04-05 17:39:51 -04:00
logo.py Update CLI logo (#2220) 2025-10-22 21:29:04 -04:00
loq.toml Split large test files to comply with loq line limit (#3328) 2026-02-28 11:21:11 -05:00
pyproject.toml Add fastmcp dev apps command with browser UI preview (#3489) 2026-03-14 12:29:37 -04:00
README.md Sync README with welcome.mdx, fix install count (#3224) 2026-02-18 18:38:20 -05:00
SECURITY.md Normalize repo references to PrefectHQ/fastmcp casing (#3218) 2026-02-18 14:51:18 -05:00
uv.lock Add fastmcp dev apps command with browser UI preview (#3489) 2026-03-14 12:29:37 -04:00

FastMCP Logo

FastMCP 🚀

Move fast and make things.

Made with 💙 by Prefect

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prefecthq%2Ffastmcp | Trendshift


The Model Context Protocol (MCP) connects LLMs to tools and data. FastMCP gives you everything you need to go from prototype to production:

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()

Why FastMCP

Building an effective MCP application is harder than it looks. FastMCP handles all of it. Declare a tool with a Python function, and the schema, validation, and documentation are generated automatically. Connect to a server with a URL, and transport negotiation, authentication, and protocol lifecycle are managed for you. You focus on your logic, and the MCP part just works: with FastMCP, best practices are built in.

That's why FastMCP is the standard framework for working with MCP. FastMCP 1.0 was incorporated into the official MCP Python SDK in 2024. Today, the actively maintained standalone project is downloaded a million times a day, and some version of FastMCP powers 70% of MCP servers across all languages.

FastMCP has three pillars:

Servers
Servers

Expose tools, resources, and prompts to LLMs.
Apps
Apps

Give your tools interactive UIs rendered directly in the conversation.
Clients
Clients

Connect to any MCP server — local or remote, programmatic or CLI.

Servers wrap your Python functions into MCP-compliant tools, resources, and prompts. Clients connect to any server with full protocol support. And Apps give your tools interactive UIs rendered directly in the conversation.

Ready to build? Start with the installation guide or jump straight to the quickstart. When you're ready to deploy, Prefect Horizon offers free hosting for FastMCP users.

Installation

We recommend installing FastMCP with uv:

uv pip install fastmcp

For full installation instructions, including verification and upgrading, see the Installation Guide.

Upgrading? We have guides for:

📚 Documentation

FastMCP's complete documentation is available at gofastmcp.com, including detailed guides, API references, and advanced patterns.

Documentation is also available in llms.txt format, which is a simple markdown standard that LLMs can consume easily:

  • llms.txt is essentially a sitemap, listing all the pages in the documentation.
  • llms-full.txt contains the entire documentation. Note this may exceed the context window of your LLM.

Community: Join our Discord server to connect with other FastMCP developers and share what you're building.

Contributing

We welcome contributions! See the Contributing Guide for setup instructions, testing requirements, and PR guidelines.