upstash/context7

Context7 — Upstash's MCP server that gives AI coding agents access to up-to-date library documentation. Solves the "agent uses outdated API" problem.

What it is

An MCP (Model Context Protocol) server from Upstash that exposes a resolve-library-id → query-docs flow: agents resolve a library by name, then fetch current documentation for it. The library covers thousands of popular packages with frequently-refreshed docs. Aimed at coding agents (Claude Code, Cursor, etc.) that need authoritative current docs rather than potentially-stale training-data knowledge.

Key features

MCP server distributing current docs for thousands of libraries.
resolve-library-id + query-docs API surface.
Hosted by Upstash; free for individual / small use.
npm-installable for self-hosting.

Tech stack

TypeScript primary.
MCP server protocol.

When to reach for it

You're a Claude Code / Cursor user and want your agent to use current API docs.
You're standing up an agent and want to mitigate stale-training-data hallucinations.

When not to reach for it

You want self-hosted by default — verify the hosted vs. self-host story for your use case.
The library you need isn't in Context7's catalog — fallback to your own docs.

Maturity signal

Actively maintained under Upstash.

Alternatives

Custom MCP server pointing at your own docs.
Direct doc-search via fetch / scrape.

Wiki: upstash/context7