Connect email via JMAP to Claude

JMAP is the modern standard for email (RFC 8621), spoken by Stalwart, Cyrus and Fastmail, among others. Through an MCP server, Claude can search your mailbox, read and summarise messages, and prepare replies.

For Stalwart 0.16 and later, JMAP is the right way: the old REST administration API was removed there, and many older MCP servers built on it no longer work.

Important: emails come from outside. Anyone can send you text that tries to make the AI do something. That is why the server sends, deletes and moves messages only after your explicit confirmation.

What you can ask Claude

• Which customer emails went unanswered this week?
• Summarise the thread with our tax adviser about the annual accounts.
• Find the Telekom invoice from September.
• Draft a polite reply to Mr Weber’s last email.

Typical tools

search_emails

Search emails by text, sender, date and folder

get_emails / get_threads

Read emails and whole threads

get_mailboxes

Show folders

mark_emails / move_emails

Flag and move (only when you allow it)

send_email / reply_to_email

Send and reply (only when you allow it, you confirm every email)

delete_emails

Delete (blocked by default)

What you need to connect

• The JMAP address of your mail server (for Stalwart e.g. https://mail.your-company.com)
• An app password for the mailbox – not the server’s admin password
• Optional: which folders Claude may see

Security

• Email content is treated as untrusted: the AI does not follow instructions in emails, and sending, moving and deleting need your confirmation.
• No access to server administration: XenMCP connects only to your mailbox, never with admin rights.
• App password encrypted (AES-256-GCM), revocable on the mail server at any time, never logged.
• The call log keeps only tool, status and duration – no subject lines, no content.

Built on

We use the open server JMAP MCP Server (MIT), build the image ourselves from a pinned version and review the tool descriptions before release.

Frequently asked questions