# Claude Code Facts

A collection of interesting and useful facts, tips, and tools for working with Claude and Claude Code — including plugins, MCP servers, and practical usage patterns.

## MCP Servers

MCP (Model Context Protocol) servers are external processes that provide tools to Claude Code via a standardized protocol. They run alongside your session and extend Claude's capabilities.

### Context7

Up-to-date documentation and code examples for any library, available directly in your Claude Code session.

- **Website:** <https://context7.com/>
- **Setup:**

  ```bash
  claude mcp add --scope user --transport http context7 https://mcp.context7.com/mcp --header "CONTEXT7_API_KEY: <YOUR_API_KEY>"
  ```

- **Note:** API key can be created for free after signing in at [context7.com](https://context7.com/)

## Skills (Slash Commands)

Skills are a different extension mechanism from MCPs. They are prompt-based extensions invoked via `/skill-name` commands directly within Claude Code — no external server required.

### AST Index

Fast code search skill for Claude Code — find classes, symbols, usages, implementations, and more across large codebases using AST parsing.

- **Repository:** <https://github.com/defendend/Claude-ast-index-search>
- **Usage:** Invoke with `/ast-index` or related commands like "find class", "search for symbol", etc.