An unofficial Fastmail MCP server

Fastmail MCP.

Modern LLMs write code fluently — and JMAP fluently in particular. So this server ships a single tool, execute. Pass it raw method calls; the agent does the rest. All on a single Cloudflare Worker.

I.

The Instrument

— The only tool —
execute
Pass raw JMAP method-call triples. The server validates, injects the accountId, and returns cleaned responses — with batching and resultOf back-references handled in a single round trip.
MCP App · UI Widget
compose_email
An interactive compose form. Pre-fills to, cc, bcc, subject, body. On supported hosts it renders inline — with send and save-draft actions.
MCP App · UI Widget
read_email
A rich reader. Fetches the email by id and renders headers, a sanitised body, and the action buttons — reply, reply all, forward.
II.

The configuration

— via the Claude CLI —
claude mcp add fastmail \
    https://fastmail-mcp.i11v.com/mcp \
    transport http \
    --scope user \
    header "Authorization: Bearer $TOKEN"
— or —
— via mcp.json —
{
  "mcpServers": {
    "fastmail": {
      "type": "url",
      "url":  "https://fastmail-mcp.i11v.com/mcp",
      "headers": { "Authorization": "Bearer $TOKEN" }
    }
  }
}