Context7 pulls current, version-specific documentation and code examples for libraries and frameworks into a coding agent's prompt, so generated code matches the API of the version in use rather than training-data snapshots. You add use context7 to a prompt, or install a rule so the agent calls it for any library question, and the service resolves the library, matches the version mentioned in the prompt, and returns relevant documentation.
It runs in two modes. CLI + Skills installs a skill that guides the agent to call the ctx7 CLI (Node.js 18 or newer, no MCP required). MCP registers a Context7 server at https://mcp.context7.com/mcp, authenticated with a bearer API key, so the agent calls documentation tools natively. npx ctx7 setup authenticates via OAuth, generates an API key, and installs the skill for Cursor, Claude Code, OpenCode, or other agents; manual MCP setup covers 30+ clients. The MCP server source is public, while the API backend, parser, and crawler are private, and library entries are community-contributed.
Features
- Version matching: mentioning a version such as "Next.js 14" in the prompt selects that version's docs
- Library IDs: a slash ID like /supabase/supabase or /vercel/next.js skips the library-matching step
- CLI commands: ctx7 library searches the index and ctx7 docs retrieves documentation
- MCP tools: resolve-library-id maps a library name to an ID and query-docs fetches documentation for a question
- Agent rules: a skill or a rule in Cursor settings or CLAUDE.md triggers Context7 without explicit prompting
- Packages: @upstash/context7-mcp server, ctx7 CLI, @upstash/context7-sdk TypeScript SDK, @upstash/context7-tools-ai-sdk Vercel AI SDK tools, and @upstash/context7-pi extension
- REST API: an HTTP API for use outside the CLI and MCP paths
- Library submissions: a process for adding a library's docs to the index
