@multimail/mcp-server

MCP server for MultiMail. Give any AI agent email capabilities through the Model Context Protocol.

Quick start

npx @multimail/mcp-server

Requires MULTIMAIL_API_KEY environment variable. Get one at multimail.dev.

Setup

Any MCP-compatible client uses the same config. Add MultiMail to your client's MCP configuration:

{
  "mcpServers": {
    "multimail": {
      "command": "npx",
      "args": ["-y", "@multimail/mcp-server"],
      "env": {
        "MULTIMAIL_API_KEY": "mm_live_...",
        "MULTIMAIL_MAILBOX_ID": "01KJ1NHN8J..."
      }
    }
  }
}

Where to add this

Client	Config file
Claude Code	~/.claude/.mcp.json
Claude Desktop	claude_desktop_config.json
Cursor	.cursor/mcp.json in your project
Windsurf	~/.codeium/windsurf/mcp_config.json
Copilot (VS Code)	.vscode/mcp.json in your project
OpenCode	mcp.json in your project
ChatGPT Desktop	Settings > MCP Servers
Any MCP client	Consult your client's docs for config location

Environment variables

Variable	Required	Description
MULTIMAIL_API_KEY	Yes	Your MultiMail API key (mm_live_...)
MULTIMAIL_MAILBOX_ID	No	Default mailbox ID. If not set, pass mailbox_id to each tool or call list_mailboxes first.
MULTIMAIL_API_URL	No	API base URL. Defaults to https://api.multimail.dev.

Tools

Tool	Description
list_mailboxes	List all mailboxes available to this API key
send_email	Send an email with a markdown body
check_inbox	List emails (filterable by unread/read/archived)
read_email	Get the full content of a specific email
reply_email	Reply to an email in its existing thread
search_identity	Look up the public identity of any MultiMail address

How it works

• You write email bodies in markdown. MultiMail converts to formatted HTML for delivery.
• Incoming email arrives as clean markdown. No HTML parsing or MIME decoding.
• Threading is automatic. Reply to an email and headers are set correctly.
• If your mailbox uses gated oversight, sends return pending_approval status. Do not retry.
• Verify other agents before communicating using search_identity.

Development

npm install
npm run dev   # Run with tsx (no build needed)
npm run build # Compile TypeScript
npm start     # Run compiled version

Testing

echo '{"jsonrpc":"2.0","method":"tools/list","id":1}' | MULTIMAIL_API_KEY=mm_live_... node dist/index.js

License

MIT