io.github.mikluko/jmap-mcp

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by mikluko · Go

JMAP Email

Email management via JMAP — mailboxes, messages, identities, and Sieve scripts

Manage emails, mailboxes, identities, and filters via JMAP protocol.

README.md5 KBView on GitHub

jmap-mcp

MCP server exposing JMAP email and Sieve script operations as tools.

Built with the Go MCP SDK (go-sdk) and go-jmap library.

Tools

Tools map closely to JMAP methods. Email mutation tools provide structured convenience wrappers over Email/set patches.

Mailbox (RFC 8621)

Tool	JMAP Method	Description
`mailbox_get`	`Mailbox/get`	Get mailboxes by ID, or list all
`mailbox_set`	`Mailbox/set`	Create, update, or destroy mailboxes

Email (RFC 8621)

Tool	JMAP Method	Description
`email_query`	`Email/query`	Search emails with filters, returns IDs and total count
`email_get`	`Email/get`	Get full content of emails by ID
`email_create`	`Email/set`	Create a new email draft in the Drafts mailbox
`email_move`	`Email/set`	Move emails to a different mailbox
`email_flag`	`Email/set`	Set or remove flags (seen, flagged, answered, draft)
`email_delete`	`Email/set`	Delete emails (move to Trash or permanently destroy)

Identity

Tool	JMAP Method	Description
`identity_get`	`Identity/get`	List sender identities (email addresses)

Submission (feature-gated)

Tool	JMAP Method	Description
`email_submission_set`	`EmailSubmission/set`	Submit a draft for delivery (requires `-enable-send`)

Sieve Scripts (RFC 9661, feature-gated)

Tool	JMAP Method	Description
`sieve_get`	`SieveScript/get`	List all scripts, or get one with full content (requires `-enable-sieve`)
`sieve_set`	`SieveScript/set`	Create, update, or destroy Sieve scripts (requires `-enable-sieve`)
`sieve_validate`	`SieveScript/validate`	Validate a Sieve script without saving (requires `-enable-sieve`)

Configuration

Env var	Required	Description
`JMAP_SESSION_URL`	always	JMAP session endpoint (e.g. `https://api.fastmail.com/jmap/session`)
`JMAP_AUTH_TOKEN`	stdio mode	Bearer token for JMAP authentication

Flag	Default	Description
`-mode`	`stdio`	Server mode: `stdio` or `http`
`-listen`	`:8080`	HTTP listen address (http mode only)
`-enable-send`	`false`	Enable the `email_submission_set` tool (off by default)
`-enable-sieve`	`false`	Enable Sieve script tools (off by default, requires JMAP server support)

In HTTP mode, the token can be passed per-request via Authorization: Bearer <token> header or jmap_token query parameter (query parameter takes precedence).

Installation

Kubernetes (Helm)

bash

helm install jmap-mcp oci://ghcr.io/mikluko/helm-charts/jmap-mcp \
  --version 0.1.0 \
  --set jmap.sessionURL="https://api.fastmail.com/jmap/session"

In HTTP mode, JMAP auth tokens are passed per-request via Authorization: Bearer header or ?jmap_token= query parameter — no static tokens are stored in the cluster.

Binary

bash

go install github.com/mikluko/jmap-mcp@latest

From source

bash

git clone https://github.com/mikluko/jmap-mcp.git
cd jmap-mcp
make install

Usage

bash

# stdio mode (default)
export JMAP_SESSION_URL=https://api.fastmail.com/jmap/session
export JMAP_AUTH_TOKEN=your-token
./jmap-mcp

# HTTP mode
./jmap-mcp -mode http -listen :8080

Build

bash

make build # Build and push container image + Helm chart
make image # Build and push container image with ko
make package # Package and push Helm chart to OCI registry
make test # Run tests
make install # Install binary locally

References

RFC 8620 — JMAP Core
RFC 8621 — JMAP Mail
RFC 9425 — JMAP Sieve Scripts
MCP Specification

Install

Configuration

Environment variables

JMAP_SESSION_URLrequired

JMAP session endpoint URL (e.g. https://api.fastmail.com/jmap/session)

JMAP_AUTH_TOKENrequiredsecret

JMAP bearer token for authentication

claude_desktop_config.json

{
  "mcpServers": {
    "jmap-mcp": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "ghcr.io/mikluko/jmap-mcp:0.10.0"
      ],
      "env": {
        "JMAP_SESSION_URL": "<YOUR_JMAP_SESSION_URL>",
        "JMAP_AUTH_TOKEN": "<YOUR_JMAP_AUTH_TOKEN>"
      }
    }
  }
}