List all mailboxes in the Fastmail account

List emails from a mailbox

Get a specific email by ID

Send an email

Reply to an existing email with proper threading headers (In-Reply-To, References). Automatically fetches the original email to build the reply chain. By default sends immediately; set send=false to save as a draft instead.

Create an email draft without sending it. Supports threading headers for replies. IMPORTANT: each call creates a new draft — do not call twice for the same message.

Edit an existing draft email. Since JMAP emails are immutable, this atomically destroys the old draft and creates a new one with the updated fields. Only fields you provide will be changed; others are preserved from the original draft.

Send an existing draft email. The draft must have recipients (to/cc/bcc) and a from address. After sending, the email is moved to the Sent folder and the draft keyword is removed.

Search emails by subject or content

List contacts from the address book

Get a specific contact by ID

Search contacts by name or email

List all calendars

List events from a calendar

Get a specific calendar event by ID

Create a new calendar event

List sending identities (email addresses that can be used for sending)

Get the most recent emails from inbox (like top-ten)

Mark an email as read or unread

Pin or unpin an email

Delete an email (move to trash)

Move an email to a different mailbox

Add labels (mailboxes) to an email without removing existing ones

Remove specific labels (mailboxes) from an email

Get list of attachments for an email

Download an email attachment. If savePath is provided, saves the file to disk and returns the file path and size. Otherwise returns a download URL.

Advanced email search with multiple criteria

Get all emails in a conversation thread

Get statistics for a mailbox (unread count, total emails, etc.)

Get overall account summary with statistics

Mark multiple emails as read/unread

Pin or unpin multiple emails

Move multiple emails to a mailbox

Delete multiple emails (move to trash)

Add labels to multiple emails simultaneously

Remove labels from multiple emails simultaneously

Check which MCP functions are available based on account permissions

Test bulk operations by finding recent emails and performing safe operations (mark read/unread)