mailbridge-mcp

name	mailbridge-mcp
description	Configure and use the Mailbridge MCP server for safe Fastmail email search, reading, thread lookup, and draft creation.

Mailbridge MCP

Use this skill when configuring or using the Mailbridge MCP server for Fastmail. Mailbridge is intentionally limited to safe email search, reading, recent listing, thread lookup, and draft creation.

Safety Rules

• Do not request, configure, or implement send, delete, or move operations.
• Treat draft_email as draft-only. It creates a draft and must not send it.
• Do not put real Fastmail API tokens, 1Password secret values, email bodies, previews, subjects, recipient lists, or raw provider responses in files, prompts, logs, or examples.
• Prefer mailbridge setup --dry-run before editing any MCP client config.

Credential Options

Environment credentials:

export FASTMAIL_USERNAME="[e-mail]"
export FASTMAIL_API_TOKEN="replace-with-fastmail-api-token"
mailbridge setup --dry-run

1Password credentials:

export MAILBRIDGE_CREDENTIAL_SOURCE="1password"
export MAILBRIDGE_1PASSWORD_VAULT="Private"
export MAILBRIDGE_1PASSWORD_ITEM="Fastmail API Token"
export MAILBRIDGE_1PASSWORD_USERNAME_FIELD="username"
export MAILBRIDGE_1PASSWORD_TOKEN_FIELD="api_token"
mailbridge setup --dry-run

The 1Password configuration names the vault, item, and fields only. The token value stays in 1Password.

Host Configuration Workflow

1. Confirm the mailbridge binary is installed and available.
2. Run mailbridge setup --dry-run.
3. Choose environment variables or 1Password references.
4. Edit the MCP host config only after the dry run prints planned checks and credential status.
5. Start the host and verify the available tools are only search_email, read_email, list_recent, find_threads, and draft_email.

Claude Desktop uses an mcpServers.mailbridge JSON entry with command = "mailbridge" and args = ["serve"].

Codex uses an [mcp_servers.mailbridge] TOML entry with command = "mailbridge" and args = ["serve"].

Cursor uses MCP JSON. For project-scoped config, use .cursor/mcp.json with an mcpServers.mailbridge JSON entry, command = "/absolute/path/to/mailbridge", and args = ["serve"]. If the installed Cursor version prefers MCP settings UI configuration, use that UI.

Skill Installation

Use the Skills CLI to install this consumer skill for the active agent host:

npx skills add rwjblue/mailbridge-mcp --skill mailbridge-mcp --agent codex
npx skills add rwjblue/mailbridge-mcp --skill mailbridge-mcp --agent claude-code
npx skills add rwjblue/mailbridge-mcp --skill mailbridge-mcp --agent cursor

Tool Use

• search_email: search by query and limit; returns message summaries.
• read_email: read one message by message_id.
• list_recent: list recent messages with a clamped limit.
• find_threads: search and return matching thread summaries.
• draft_email: create a plaintext draft only.

If a user asks to send, delete, or move email, explain that Mailbridge MCP does not support those operations and that they require a new approved design.