@whyshouldaicareone AI disaster a day, and the fix

Feed Claude Code current docs with Context7

Claude used a function from version 2 of a library that is on version 5. This guide plugs current docs into Claude Code.

The fix

Context7 is an MCP server that pulls current, version-specific docs into the chat. Add it once for all your projects. Its README recommends a free API key from context7.com/dashboard for higher rate limits. One-command alternative: npx ctx7 setup --claude (needs Node.js 22.13 or newer).

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

Use it

Add "use context7" to the prompt and say the version you run. If you know the library, give its ID to skip the lookup.

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How do I set up a Next.js 16 proxy? use context7

Implement basic authentication with Supabase.
use library /supabase/supabase for API and docs.

Check it worked

The server should show as connected. Then make Claude prove where an answer came from.

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claude mcp list
# inside Claude Code:
/mcp

Name the doc page for every function you used.
If you cannot, say so.

Pro tip: stop typing it, stop the prompts

Add this rule to CLAUDE.md so Claude reaches for Context7 on its own: "Always use Context7 when I need library/API documentation, code generation, setup or configuration steps." Then allow the server's tools in .claude/settings.json so each lookup does not ask. The rule name is mcp__ plus the server name, here context7.

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{
  "permissions": {
    "allow": ["mcp__context7__*"]
  }
}

Pro tip: docs you already have

Type @ and a path to put a local file in the conversation, for example @docs/api.md. It is included when it fits the Read tool limit of 25,000 tokens; a text file over 256KB is not. For a web page, paste the URL and ask Claude to read it: Claude Code fetches pages with WebFetch and asks first, except for a built-in set of documentation domains.

Common mistake

Not saying the version. Context7 matches the version you mention, so write the one in your package.json. A prompt with no version leaves Claude free to answer for the one it remembers.

Official docs

One fix of twenty: the whole Claude Code survival kit.

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