mu-mcp

mu-mcp: MCP Server for the mu Mail Indexer

A Model Context Protocol (MCP) server for querying your local mu mail index. This server enables fast, structured mail search from Claude Desktop and other MCP clients.

Features

• Stdio MCP server for easy integration
• Tools: search_emails, view_emails (HTML-only emails converted to text), list_attachments, open_attachment (saves to a temp dir and optionally opens with the default OS viewer), and mu_help for the full mu reference on demand.
• Small context footprint: a short query guide lives in the tool description; the full man pages are only loaded when the model asks for them.
• Fast, flexible mail search using the mu index
• Claude Desktop ready: simple installation and config
• Python, uv, and MCP SDK based

Installation

Requires mu installed and your mail indexed (mu init + mu index).

Clone this repository and install dependencies:

git clone https://github.com/danielfleischer/mu-mcp.git
cd mu-mcp
uv sync

Usage

Run the MCP Server

With uv:

uv run --directory . mcp run mu_mcp/mu_mcp.py

Claude Desktop Integration

Add to your claude_desktop_config.json:

"mcpServers": {
  "email": {
    "command": "uv",
    "args": [
      "run",
      "--directory",
      "PROJECT_PATH",
      "mcp",
      "run",
      "mu_mcp/mu_mcp.py"
    ]
  }
}

Replace PROJECT_PATH with the path to your cloned repo.

Claude Code Integration

claude mcp add email -s user -- uv run --directory PROJECT_PATH mcp run mu_mcp/mu_mcp.py

Use -s local instead to enable it only in the current project. Check it with /mcp in a new session.

Query

Ask Claude to find emails, e.g. "Find emails with a PDF attachment that were sent last April and open the PDF", "Show me the email I received from Alice last week", or "Find emails with the subject 'Meeting Notes'".

Development

• Adding a tool to view an email.
• Adding a tool to find and download attachments.
• Progressive disclosure of the mu man pages via mu_help.