Claude Code burns ~15–20% of your tokens on a 3-word status line

When you request a Next.js route, Supabase sign-up form, or Cloudflare Worker from your coding assistant, it writes code that interacts with an API that may have been outdated for a year. Sometimes, the model invents non-existent functions. This happens because the model's training data is older than the libraries you just installed.

Context7 by Upstash resolves this issue by retrieving current, version-specific documentation and code examples directly from the API and inserting them into your agent's context when it needs them. Context7 can work seamlessly within Cursor, Claude Code, VS Code, and Codex, and supports manual setup for 30+ MCP clients. This guide walks you through a one-command setup, manual setup for Cursor and Claude Code, effective prompts, and a rule to prevent outdated API code.

To get started, ensure your Node.js version is 22.13 or newer. You can either use the Context7 CLI with one command or set it up manually. For Cursor and Claude Code, a free API key from the Context7 dashboard is recommended for higher rate limits. The fast way is to execute the one-command setup. To manually set it up in Claude Code, use the claude mcp add command with your API key.

For Cursor, navigate to Cursor Settings, then Tools & MCP, and New MCP Server. Add the URL and API key to your config file. Once installed, use the command "use context7" at the end of your prompt to retrieve the latest documentation and code examples. This approach ensures you never have to manually ask for updated information, as the system will automatically fetch the current data for you.