Context7

What it does (plain English)

Claude learned about programming libraries from training data that has a cut-off date. When a library changes after that, Claude can confidently suggest functions that were renamed or removed. Context7 fixes this by fetching the current documentation and code examples for the library you name and putting them straight into Claude’s context.

It is an MCP server (a plug-in that gives Claude a new ability) with exactly two tools:

Tool	What it does
resolve-library-id	Turns a name like “next.js” into a Context7 library ID such as /vercel/next.js
query-docs	Pulls the relevant docs and examples for that ID and your question

Context7 is run by Upstash. The MCP server code is open source (MIT), but the README notes the API backend, parsing and crawling engines are private.

Is it for you?

Pick it if you build with fast-moving tools (Next.js, Astro, Supabase, Tailwind, Cloudflare Workers) and you have ever pasted an error back into Claude only to learn the method it suggested does not exist. It is one of the easiest servers to start with: two tools, no account required to try it.

You do not need it for general writing or non-code work. And remember the docs come from a community-contributed index; Context7’s own disclaimer says it cannot guarantee accuracy or security of every library page.

What you can do with it

• Add “use context7” to a prompt: the README’s own example is “Create a Next.js proxy that checks for a valid JWT in cookies and redirects unauthenticated users to /login. use context7”.
• Skip the lookup step: if you know the ID, say it. “Implement basic authentication with Supabase. use library /supabase/supabase for API and docs.”
• Ask for a specific version: “How do I set up a Next.js 16 proxy? use context7” and it matches the version.
• Make it automatic: add a line to your project’s CLAUDE.md such as “Always use Context7 when I need library/API documentation, code generation, setup or configuration steps without me having to explicitly ask.”

How to set it up

1. Get a key (recommended). Sign in at https://context7.com/dashboard and create a free API key. The README recommends this for higher rate limits.

2. Claude Code, remote server:

   claude mcp add --scope user --header "Authorization: Bearer YOUR_API_KEY" --transport http context7 https://mcp.context7.com/mcp

   Or local server:

   claude mcp add --scope user context7 -- npx -y @upstash/context7-mcp --api-key YOUR_API_KEY

3. Claude Desktop or claude.ai: go to Settings > Connectors > Add custom connector. Name it Context7 and use the URL https://mcp.context7.com/mcp. Context7’s client page does not show a way to pass an API key in this flow, so we can’t confirm which rate limits apply there. For Desktop with a key, use the config file instead:

   {
     "mcpServers": {
       "context7": {
         "command": "npx",
         "args": ["-y", "@upstash/context7-mcp", "--api-key", "YOUR_API_KEY"]
       }
     }
   }

   Anthropic’s help centre lists custom connectors for Pro, Max, Team and Enterprise plans; on Team and Enterprise only an Owner can add one.

4. One-command option: npx ctx7 setup --claude signs you in, creates a key and configures Claude Code. It needs Node.js 22.13 or newer. Undo it with npx ctx7 remove.

What we checked (2026-10-18): we ran npx -y @upstash/context7-mcp (version 4.4.2) without a key, completed the MCP handshake and listed both tools. A follow-up resolve-library-id call for “astro” returned “Monthly quota exceeded. Create a free API key at https://context7.com/dashboard for more requests.” Our sandbox shares its network address with other traffic, so your keyless experience may differ, but it shows why the free key is worth the minute it takes.

Watch out for

• Keyless limits are real. See our test above. Set up the key before you rely on it.
• Docs are community-indexed. Context7 says projects are maintained by their owners, not Context7, and provides a Report button for suspicious content. Treat fetched docs as helpful input, not gospel.
• Keep your key out of shared files. If you add it with --scope project, it lands in .mcp.json, which teams often commit to Git.
• It answers library questions only. It will not help with your business logic or your own private code.

Alternatives

• Cloudflare’s documentation server (https://docs.mcp.cloudflare.com/mcp) if you only need Cloudflare docs.
• Vercel MCP and Supabase MCP both include docs-search tools for their own platforms.
• Exa MCP for broader web search when the answer is in a blog post or GitHub issue rather than official docs.