Zig Docs MCP

Model Context Protocol (MCP) server that provides up-to-date documentation for the Zig programming language standard library and builtin functions.

It uses the same approach as Zig's official autodoc (ziglang.org) by reading STD lib source files directly through a WASM module. However instead of returning HTML, it outputs Markdown which significantly reduces token usage.

[!TIP] Add use zigdocs to your prompt if you want to explicitly instruct the LLM to use Zig docs tools. Otherwise, LLM will automatically decide when to utilize MCP tools based on the context of your questions.

Installation

Claude Code

claude mcp add zig-docs npx -y zig-mcp --version master --update-policy manual

Claude Desktop

Add to your MCP configuration:

{
  "mcpServers": {
    "zig-docs": {
      "command": "npx",
      "args": ["-y", "zig-mcp", "--version", "master", "--update-policy", "manual"]
    }
  }
}

Tools

• list_builtin_functions - Lists all available Zig builtin functions. Builtin functions are provided by the compiler and are prefixed with '@'. The comptime keyword on a parameter means that the parameter must be known at compile time. Use this to discover what functions are available, then use 'get_builtin_function' to get detailed documentation.
• get_builtin_function - Search for Zig builtin functions by name and get their documentation, signatures, and usage information. Returns all matching functions ranked by relevance.
• search_std_lib - Search the Zig standard library for declarations by name. Returns a list of matching items with their fully qualified names. Use this to discover available types, functions, and constants in the standard library.
• get_std_lib_item - Get detailed documentation for a specific standard library item by its fully qualified name (e.g., "std.ArrayList.init"). Returns comprehensive documentation including function signatures, parameters, errors, examples, and source code. Set get_source_file: true to retrieve the entire source file where the item is implemented.

Commands

The CLI provides flexible options for version control and update management:

# Start MCP server with defaults (master branch, manual updates)
zig-mcp

# Use specific Zig version
zig-mcp --version 0.13.0

# Enable automatic daily updates
zig-mcp --update-policy daily

# Update documentation without starting server
zig-mcp update --version 0.14.1

# Start local web server to view documentation
zig-mcp view --version 0.14.1

Version options:

• master (default) - Latest development version from Zig's master branch
• 0.14.1, 0.14.0, etc. - Specific Zig release versions

Update policies:

• manual (default) - No automatic updates, manual control only
• daily - Check for documentation updates once per day
• startup - Update documentation every time the server starts

Cache

Documentation is fetched from ziglang.org and cached in platform-specific directories:

• Linux: ~/.cache/zig-mcp/
• macOS: ~/Library/Caches/zig-mcp/
• Windows: %LOCALAPPDATA%\zig-mcp\