What you can do with Fastmail

Built for

Operations Teams, Executive Assistants, Founders, Client Services Managers

Example workflows

Inbox morning brief

Daily triage without opening every thread manually.

Try this

Search my Fastmail inbox for unread messages from the last 24 hours and summarize what needs a reply today.

Thread catch-up

Long-thread recap for operators joining mid-conversation.

Try this

Pull the full Fastmail thread about the Riverside Dental contract and give me a bullet summary of what was decided and who owes a reply.

Send a follow-up

Send workflow grounded in the existing conversation.

Try this

Draft and send a Fastmail reply to the latest message in the Acme Dental onboarding thread — confirm next steps and ask for their preferred kickoff date.

Masked address for a signup

Privacy-forward signups without digging through settings.

Try this

Create a new Fastmail masked email address for a Harbor Legal software trial and tell me the address to paste at checkout.

Context to know first

What is Fastmail MCP?

It lets AI agents in Cursor, Claude, or ChatGPT work with your Fastmail mailbox — search and read mail, triage unread messages, send replies, and manage masked addresses — after you connect in MCPBundles.

Who is this for?

Operators and assistants who live in email and want inbox summaries, thread catch-ups, and send workflows from chat instead of copying subjects between tabs.

Can an agent delete my mail?

Agents can move, mark read, send, and manage drafts when you ask. Permanent deletion only happens when you explicitly request it.

Related editorial

Fastmail Email Workflows with AI

How AI agents search inboxes, summarize threads, send follow-ups, and create masked addresses without living inside the mail client.

Read article

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. Fetch by ...

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 get thread content to fetch normalized mes...

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; fetch by email id to read a draft body, or delete draf...

Fastmail List Email Attachments

List attachments for an email. Returns attachment metadata including blob_id/name/type/size. Download a specific attachment to S3 for a presigned URL ...

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). Fetch full messa...

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 Fastmail MCP?

It lets AI agents in Cursor, Claude, or ChatGPT work with your Fastmail mailbox — search and read mail, triage unread messages, send replies, and manage masked addresses — after you connect in MCPBundles.

Who is this for?

Operators and assistants who live in email and want inbox summaries, thread catch-ups, and send workflows from chat instead of copying subjects between tabs.

Can an agent delete my mail?

Agents can move, mark read, send, and manage drafts when you ask. Permanent deletion only happens when you explicitly request it.

How do I connect?

Open the Fastmail skill page in MCPBundles, add your connection, and create an integration token in Fastmail Settings under Privacy & Security. Usage follows your Fastmail plan.

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

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

One-click install:

The link prefills the Add custom connector dialog — you still review the values and click Add, then Connect to complete OAuth.

Or add manually

  1. Open claude.ai → Settings → Connectors.
  2. Click the + button and choose Add custom connector.
  3. Set Name to Fastmail and paste the MCP URL into Remote MCP server URL.
  4. Click Add. Fastmail will appear under Not connected — select it and click Connect to complete OAuth.
Name: Fastmail
Remote MCP server URL: https://mcp.mcpbundles.com/bundle/fastmail
Authentication: OAuth

Custom connectors at claude.ai require a paid Claude plan (Pro, Max, Team, or Enterprise).

Ready to use Fastmail?

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

Fastmail MCP Server