# Context7

> Library and framework documentation lookup.

- **MCP server name:** `context7` (runs locally via npx)
- **Prompt snippet:** [prompts/tools/context7.md](../../prompts/tools/context7.md)

## What It Is

Context7 is a purpose-built MCP server for fetching current library, framework, SDK, API, and CLI documentation. It returns structured, version-aware results — meaningfully better than Argos for "how does this library work" type questions.

## What It's Good For

- API syntax, method signatures, configuration options for libraries
- Framework setup instructions and patterns (Django, React, Next.js, Tailwind, FastAPI, etc.)
- CLI tool usage and flags
- Version migration guides
- Library-specific debugging — "why does this configuration fail"

Use Context7 even for well-known libraries — training data may be stale on recent releases.

## What It's Not Good For

- Refactoring or writing scripts from scratch — Context7 documents, doesn't implement
- General programming concepts — Context7 indexes libraries, not theory
- Code review — use the agent's own judgment, not external docs
- Business logic debugging — Context7 won't know your code

## Known Gotchas

- **Resolve the library ID first.** Context7 typically expects a library identifier; `resolve-library-id` style calls precede `query-docs` calls.
- **Version matters.** When library behavior is version-specific, include the version in the query. The doc index may have multiple versions.
- **Prefer over web search for libraries.** When the question is "how does X library work," Context7 is the right first stop. Argos is the fallback.