Email

Fastmail MCP Server

Connect your account, then chat with AI to run tools.

Fastmail is an email provider with a modern standards-based API via JMAP. These tools let you list mailboxes, search and fetch emails, triage messages (read/unread, move), send email via JMAP submission, and manage Fastmail Masked Email addresses.

22 tools
Agent guide included
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AI Skill
SKILL.md

Domain knowledge for Fastmail — workflow patterns, data models, and gotchas for your AI agent.

Fastmail

Fastmail uses JMAP for email. Mailboxes, search, fetch, triage, send, masked email, drafts.

Data Model

  • Mailboxes (provide mailbox_id for search/fetch), Emails (search by mailbox_id, filter; fetch by id), Threads (fetch by id), Masked Emails, Drafts (create, list, fetch, delete).

Gotchas

  • JMAP: Session URL discovered at runtime; apiUrl + account ids from session.
  • mailbox_id: Required for search; from list mailboxes.

Tools in this Server (22)

Fastmail Archive Email

Archive an email in Fastmail. This removes the message from the Inbox mailbox and adds it to the Archive mailbox (by mailbox role), while preserving a...

Fastmail Batch Mark Read Unread

Mark multiple emails read/unread using one JMAP Email/set call by toggling the $seen keyword on each id. Use this to triage many messages quickly.

Fastmail Batch Move Emails

Move multiple emails into a mailbox using a single JMAP Email/set call. This REPLACES mailboxIds for each email with only the target mailbox id.

Fastmail Create Draft

Create a draft email in Fastmail. This uploads an RFC822 message and imports it into the Drafts mailbox. Returns the created draft email id. Use fastm...

Fastmail Create Masked Email

Create a new Fastmail Masked Email address via MaskedEmail/set. Returns the created masked email object (including the generated email address).

Fastmail Delete Draft

Delete a Fastmail draft by destroying the underlying Email object via JMAP Email/set destroy. This permanently removes the draft.

Fastmail Fetch Email

Fetch an email by id via JMAP Email/get and return normalized fields (from/to/subject/dates + body_text). Use include_html=true when you need HTML; ot...

Fastmail Fetch Thread

Fetch a thread by id via JMAP Thread/get. Returns thread metadata including the emailIds in the thread. Use fastmail_get_thread_content to fetch norma...

Fastmail Get Attachment Download Url

Get a short-lived download URL for a Fastmail attachment. The returned URL expires; call this tool again to generate a fresh URL if needed.

Fastmail Get Thread Content

Fetch a Fastmail thread and return normalized content for each message (headers + body_text). This is the best tool for reviewing an entire conversati...

Fastmail List Drafts

List email drafts in Fastmail (messages stored in the Drafts mailbox). Returns draft email ids; use fastmail_fetch_email to read a draft body, and fas...

Fastmail List Email Attachments

List attachments for an email. Returns attachment metadata including blob_id/name/type/size. Use fastmail_download_attachment_to_s3 to fetch a specifi...

Fastmail List Mailboxes

List mailboxes (folders) in Fastmail via JMAP Mailbox/get. Results include id, name, role (e.g. inbox, trash), and other metadata. Use mailbox ids fro...

Fastmail List Masked Emails

List Fastmail Masked Email addresses via the Fastmail JMAP masked email extension (MaskedEmail/get). Returns all masked emails (ids=null) with metadat...

Fastmail Mark Read Unread

Mark an email as read/unread in Fastmail via JMAP Email/set by toggling the $seen keyword. Use this for inbox triage.

Fastmail Move Email

Move an email to a target mailbox by setting mailboxIds via JMAP Email/set. This is the building block for archive/trash workflows (move to archive or...

Fastmail Reply Email

Reply to an email in Fastmail using JMAP. Supports reply-all and HTML bodies. This preserves threading by setting inReplyTo and references.

Fastmail Search Emails

Search Fastmail emails via JMAP Email/query. Returns matching email ids plus query metadata (queryState, total, canCalculateChanges). Use returned ids...

Fastmail Send Email

Send an email from Fastmail using JMAP. Supports multiple recipients, CC/BCC, Reply-To, and HTML bodies. For replies in an existing conversation, use ...

Fastmail Trash Email

Move an email to Trash in Fastmail by setting mailboxIds to the Trash mailbox (role=trash). Use this for delete workflows.

Fastmail Update Masked Email

Update an existing Fastmail Masked Email via MaskedEmail/set. Supports changing state (enabled/disabled/deleted) and metadata fields (forDomain, descr...

Fastmail Validate Token

Validate the Fastmail API token by fetching the JMAP session and checking capabilities. Returns 'ok' when mail + submission capabilities are present; ...

Frequently Asked Questions

What is the Fastmail MCP server?

Fastmail is an email provider with a modern standards-based API via JMAP. These tools let you list mailboxes, search and fetch emails, triage messages (read/unread, move), send email via JMAP submission, and manage Fastmail Masked Email addresses. It provides 22 tools that AI agents can use through the Model Context Protocol (MCP).

How do I connect Fastmail to my AI agent?

Add the MCPBundles server URL to your MCP client configuration (Claude Desktop, Cursor, VS Code, etc.). The URL format is: https://mcp.mcpbundles.com/bundle/fastmail. Authentication is handled automatically.

How many tools does Fastmail provide?

Fastmail provides 22 tools that can be called by AI agents, along with a SKILL.md that gives your AI agent domain knowledge about when and how to use them.

What authentication does Fastmail require?

Fastmail uses API Key. Fastmail requires credentials. Connect via MCPBundles and authentication is handled automatically.

Setup Instructions

Connect Fastmail to any MCP client in minutes

https://mcp.mcpbundles.com/bundle/fastmail

What is MCP?

Model Context Protocol lets AI tools call external capabilities securely through a single URL. This bundle groups tools behind an MCP endpoint that many clients can use.

Use this bundle in 3 steps

  1. Copy the MCP URL above
  2. Open your AI tool and add a new MCP/connector
  3. Paste the URL and follow any auth prompts

Claude Desktop Users

Skip the manual setup! Use the .mcpb file format for one-click installation. Check the Claude Desktop tab for setup instructions.

Pick your tool tab for exact steps

Select ChatGPT, Cursor, Claude Code, or another tab for copy-paste config.

Ready to use Fastmail?

Sign in to connect your credentials and start running tools from the chat.

Fastmail MCP Server & Skill — 22 Tools