Context7

Stale training data is why generated code calls APIs that no longer exist; Context7 fixes the problem at the prompt. Upstash's MIT-licensed MCP server pulls current, version-specific documentation and code examples for a requested library straight from the source and injects them into model context on demand, so answers track the release actually installed rather than whatever the model memorized. Setup is one command, npx ctx7 setup on Node.js 18 or newer, which configures either MCP mode or a CLI-plus-skills mode for Cursor, Claude Code, OpenCode, and more than 30 other MCP clients. An API key is optional and free from the context7.com dashboard, raising rate limits on the hosted documentation index that backs the server; that hosted dependency means the tool does not work offline. Libraries are indexed continuously and anyone can submit new ones for inclusion. With over 61,000 GitHub stars it has become a default install alongside coding agents, frequently cited as the simplest single upgrade to code generation quality on fast-moving frameworks.