MCP tool reference

atbridge mcp runs a Model Context Protocol server over stdio, exposing your Thunderbird emails, calendars, contacts, notes and tasks as tools an AI client can call. The server name in a client’s config is atbridge.ai.

New to atbridge over MCP? The /mcp overview — what it does, which clients (Claude Desktop, Cursor, JetBrains, Antigravity…), and how it compares to a cloud mail MCP.

// In your MCP client's config (see the Connect-your-AI setup pages)
{
  "mcpServers": {
    "atbridge.ai": { "command": "atbridge", "args": ["mcp"] }
  }
}

Tools by area

Each page lists that area’s read tools (always on) and write tools (opt-in — see below).

mail Fetch, search, list, get, thread, attachments — and send, reply, forward, move, delete, mark, folders.

calendar Events, clash-check, find-slots, settings — and create, update, delete, RSVP.

contacts Contacts + mailing lists across every address book.

notes @bridge Notes — pull an artifact as context, or save one back.

tasks To-dos (VTODO) on your task-capable calendars.

AI — Branded Email Render @bridge Branded Email; list & save templates.

system — accounts, license, updates Pick a sender identity; subscription, devices, update state.

Read vs write

Read tools are always registered; no opt-in. Numeric ids and RFC Message-IDs are interchangeable wherever an identifier is accepted.

Pagination & counting — every list/search tool (mail_search/mail_list, contacts_list/contacts_search, calendar_events_search, tasks_list, notes_list) accepts offset (skip the first N; pair with limit to page — offset:20, limit:20 = results 21–40) and count: true (return { total, approx } for the same filters instead of the items). Counts are exact for contacts/calendar/tasks/notes; best-effort for mail (scope with folder/since/ until for an exact figure — indicated by approx).

Lean results & gist — mail_search and mail_list return lean rows by default: id, date, from/to, subject, read/flagged — enough to pick a message without over-fetching. Add snippet: true for a ~200-char plaintext gist per result (cleaned of quote markers and separator noise, so a one-line summary needs no follow-up mail_get), or verbose: true for the full routing metadata (headerMessageId, folderLabel, accountName, conversationId). Anything else is one mail_get by id away.

Write tools are registered only when ATBRIDGE_ALLOW_WRITES=1 is set in the MCP entry’s env, so an agent can’t send or destroy anything unless you turn it on. Enable it with atbridge mcp setup --client <id> --allow-writes, or the Allow writes toggle in the extension’s Connect your AI (MCP) settings, then restart the client.

Admin tools — the account/system tools (billing, devices, version, auto-update) are registered only when ATBRIDGE_ADMIN_TOOLS=1 is set (default off). They’re ~never needed for everyday mail/calendar work, so leaving them off keeps the default tool surface lean; turn them on the same way you enable writes when you want the AI to check your subscription or trigger an update.

{
  "mcpServers": {
    "atbridge.ai": {
      "command": "atbridge",
      "args": ["mcp"],
      "env": { "ATBRIDGE_ALLOW_WRITES": "1" }
    }
  }
}

MCP tool reference

Tools by area

Read vs write

See also