Jmap MCP

What wyattjoh/jmap-mcp MCP server does

The wyattjoh/jmap-mcp MCP server connects an MCP client to a JMAP-compliant email service. It supports common mailbox and message workflows without requiring the agent to construct JMAP requests directly. Supported services include JMAP deployments such as Cyrus IMAP, Stalwart Mail Server, and FastMail, provided valid JMAP credentials are available.

Mailbox discovery is the starting point for many operations. get_mailboxes returns folder IDs, names, hierarchy information, and other metadata. Those IDs can then be used to constrain searches or select a destination for moved messages.

How it works

The server is implemented in Deno and uses the jmap-jam client library for protocol access. MCP tools adapt typed JMAP operations and validate inputs with Zod schemas. Run it over stdio from an MCP client, using Deno permissions for network access and environment-variable access.

Search results contain email IDs rather than complete messages. Call get_emails with those IDs and request only the properties needed for the task. Body content requires the appropriate body-related properties. Thread lookup is a separate step: get_threads returns the message IDs associated with supplied thread IDs, after which get_emails can retrieve their content.

The server also supports state-based polling. get_email_changes reports message IDs created, changed, or destroyed since a previous email state. get_search_updates reports additions and removals for an earlier search, but the original filter parameters must be supplied again.

Setup and configuration

The wyattjoh/jmap-mcp MCP server requires Deno 2 or later, access to a JMAP server, and valid authentication credentials. Configure these environment variables:

• JMAP_SESSION_URL: Required JMAP session endpoint, normally the server’s well-known JMAP URL.
• JMAP_BEARER_TOKEN: Required bearer token used for authentication.
• JMAP_ACCOUNT_ID: Optional account identifier; the client can detect it when omitted.

A stdio configuration invokes deno run with network permission for the JMAP host and environment permission for these variables. Replace the example FastMail hostname with the hostname of the selected JMAP service. The project also documents installation as a Claude Code plugin through its marketplace.

Tools and capabilities

The wyattjoh/jmap-mcp MCP server provides tools for:

• Searching by text, sender, recipient, subject, mailbox, keywords, and date range. Filters are combined with AND behavior, and results support pagination.
• Fetching selected email properties, retrieving thread membership, and managing read or flagged status.
• Moving messages, adding or removing mailbox memberships, and permanently deleting messages. Permanent deletion cannot be undone; moving mail to Trash is the recoverable alternative.
• Sending new messages with plain-text or HTML bodies, and replying with automatic recipient and subject handling, including reply-all support.
• Tracking email changes and updates to an earlier search query.

Operations accept bounded batches and pagination parameters where documented. Capability-based registration distinguishes read-only and submission functionality.