Busymail

Busymail is an email client for the mailboxes you connect, and it exposes them over MCP. Point an AI client at it - Claude, or anything else that speaks MCP - and it can read your mail, search it, tidy it up, and write replies for you. It is not a mailbox you move to: you keep your accounts where they are.

Nothing sends without you

A token can never send mail. When an assistant writes a reply, the message is queued and waits under Approvals in Busymail until you approve or reject it, with the recipients, subject and body all there to read first. Approving happens while you are signed in, so the token that wrote a message cannot approve it.

What a token may do

You pick the access when you create a token.

• Read - message content, summaries, search and sent mail. Every token has this. When a client connects through the script Busymail serves, it can also save an attachment as a file on your own machine, which stays there until you or your system removes it.
• Organise - archive, unarchive, pin and unpin. Archiving really moves the mail out of your inbox on your mail server, so it changes what you see in every other mail app too.
• Send - queues mail for you to approve. It also reads everything already queued on your account, whichever client queued it, so a token with this access sees the recipients, subject and body of those messages. When a client connects through the script Busymail serves, attaching a file lets it read that file from your own machine.

No token can change your settings, your password or your two-factor, add or remove an email account, or create and revoke tokens. Those stay with you. You can revoke a token at any time without affecting the others.

Connecting a client

Pick the client you use, and put one of your own tokens in place of the placeholder.

Claude Code

Direct HTTP, with no local script:

This connection has no download tool and cannot attach a file by path, so use it or the local script, not both. If you already added either one, run claude mcp remove busymail before adding the other:

An .mcp.json entry for direct HTTP needs "type": "http" and "url": "https://busymail.app/mcp", with the token in a "headers" object, because a url with no type is read as a stdio server.

Claude Desktop and Cursor

Add the busymail entry under mcpServers in the client's config file, keeping any servers already there: Claude Desktop keeps it in Settings > Developer > Edit Config, and Cursor in ~/.cursor/mcp.json.

Restart the client after adding the entry: quit and reopen Claude Desktop, or restart Cursor, and the server appears with its tools.

That config runs a small script from Busymail on your own machine, which is what lets files move between your disk and your mail without passing through the AI client. You can attach a file by giving its path, and the script reads it from disk and sends it on; and an assistant can save an attachment out of your mail, which the script writes to a new folder in your temporary directory and tells it where. The script is fetched each time your client starts the server, so it always matches Busymail and nothing is cached. It reads whatever file a tool call names, so treat a tool call that attaches one as you would any other access to your files. Downloaded attachments are left where they were written, for your system to clear with the rest of your temporary files.

It needs Node, curl and a POSIX shell, so on Windows use the direct connection below instead.

For a remote server, Cursor documents url with a headers object and no type, while Claude Desktop adds one on an individual plan under Connectors, which sits under Plugins after the rename and Customize until the rename reaches you, rather than in this file.

If your client cannot run a local script

Point it at https://busymail.app/mcp as a Streamable HTTP MCP server and send the token in an Authorization: Bearer header. Attaching a file by path needs the local script, and so does any tool that downloads an attachment: the direct connection has no download tool and never writes to your disk. The bytes are still reachable by a client that can make an authenticated request of its own. Over direct HTTP the client sends a file as base64 itself, which keeps attachments well below the 25 MiB Busymail accepts.

Getting a token

Tokens live in Busymail under Settings, MCP. You need an account to create one. Free for 14 days, no card. Then $15 a month plus VAT or sales tax where it applies. Get started