Local Fastmail MCP Server

A locally-hosted MCP server that connects your AI assistant to Fastmail via the JMAP API. The local fastmail mcp mcp server wraps that behind the Model Context Protocol, so an assistant can use it through 7 defined tools rather than through you.

What it actually does

A locally-hosted Model Context Protocol server that connects your Fastmail account to any MCP-compatible AI assistant (such as Claude Desktop, Cursor, or similar tools).

Its toolset

Everything the assistant can do here goes through one of these:

• list_mailboxes — Discover all labels, folders, and mailboxes in your account. Returns each mailbox's ID, name, role, unread/total counts, and permissions
• list_emails — Query emails by folder, keyword search, or read/unread status. Supports pagination for large result sets
• read_email — The read_email tool exposed by this server
• send_email — The send_email tool exposed by this server
• mark_email_read — The mark_email_read tool exposed by this server
• move_email — The move_email tool exposed by this server
• delete_email — The delete_email tool exposed by this server

Configuration

You will need 2 environment variables: FASTMAIL_EMAIL, FASTMAIL_API_TOKEN. The server will not start without them, which is usually why the tools fail to appear on a first run. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

Adding it to your client

Being a remote server, there is no local install. You register the endpoint with your client, authorise it once, and the tools appear.

When to reach for it

Among the developer tooling options, the useful question is rarely "what can it do" but "what does it cost you to run" — permissions, credentials, and how much of your context its toolset consumes. Local Fastmail MCP's toolset — list_mailboxes, list_emails, read_email and 4 more — is a fair guide to whether it matches your workflow. It is maintained by mattriffle; worth a glance at recent repository activity before you build anything load-bearing on it.

This entry was verified against Local Fastmail MCP's own documentation before publication; SyncDev keeps the directory reviewed rather than auto-generated.

Caveats

• Your data travels to the provider's service, so the usual questions apply about what you send and what they retain.
• Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
• MCP clients confirm each tool call by default. Leave that on until you have watched what the local fastmail mcp mcp server does with a few real requests.