Connect atbridge.ai to Claude Desktop

In short: Claude Desktop reaches atbridge.ai over MCP. Add an atbridge MCP entry to Claude Desktop’s config — run atbridge mcp setup --client claude, or paste the snippet below — then fully quit and restart Claude Desktop. About two minutes.

If you haven’t installed atbridge.ai yet, start with Install atbridge.ai.

Claude Desktop can’t run terminal commands on its own, so it talks to atbridge.ai over an MCP connection — that’s what you’ll set up below. New to how this works? See How your AI connects for the two-minute overview.

Once it’s connected you can even build a skill — like a daily agenda that folds your unread mail and calendar into one brief. See Where you can use atbridge.ai for the idea.

1. Open Claude Desktop’s settings file

In Claude Desktop, go to Settings → Developer → Edit Config. That opens a file called claude_desktop_config.json in your editor.

2. Add atbridge.ai

If the file is empty, paste this:

claude_desktop_config.json

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

If you already have other tools configured, just add the atbridge entry inside the existing mcpServers block:

{
  "mcpServers": {
    "filesystem": { /* ... */ },
    "atbridge.ai": {
      "command": "atbridge",
      "args": ["mcp"]
    }
  }
}

Caution

JSON doesn’t allow trailing commas. Double-check after you paste.

3. Restart Claude Desktop

Fully quit the app — Cmd-Q on macOS, File → Quit on Windows. Just closing the window isn’t enough.

Relaunch. Go to Settings → Developer → MCP Servers — you should see atbridge listed with a green status dot.

4. Try it

In a new chat:

List the 5 most recent emails in my Thunderbird inbox.

If you see a list, you’re done.

5. Let atbridge compose, send & edit (optional)

By default the atbridge.ai MCP is read-only — it can search, read, and summarise, but it can’t send, draft, move, or delete anything. That’s a deliberate safety default: an AI shouldn’t be able to send or destroy mail unless you explicitly turn it on. (If you ask Claude to draft or send while this is off, it’ll tell you the write tools exist but are disabled — and how to enable them.)

To unlock the write tools — mail_send (including drafts via mode), reply, forward, move, delete, plus contacts and calendar edits — add an env block:

claude_desktop_config.json

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

Tip

Prefer one click? In Thunderbird, open the atbridge.ai extension’s Settings → Connect your AI (MCP), tick “Allow writes”, then hit Set up Claude Desktop — it writes the env for you.

Fully quit and restart Claude Desktop, then try:

Draft a reply to the last email from Alex thanking them and proposing Thursday.

When it doesn’t work

”No atbridge.ai tools” or red status dot

The most common cause: Claude Desktop can’t find the atbridge.ai command. Fix it by giving the absolute path:

Windows

Find the path:

(Get-Command atbridge).Source

Then use it in claude_desktop_config.json:

"command": "C:\\Users\\you\\AppData\\Local\\Programs\\atbridge\\atbridge.exe"

Note the doubled backslashes — JSON requires it.

macOS / Linux

Find the path:

which atbridge

Then use it:

"command": "/usr/local/bin/atbridge"

Save, fully quit Claude, restart.

”Bridge not reachable” on first tool call

That means Thunderbird isn’t running. Open it, then ask again.

”You’ve hit your plan’s monthly limit”

Check your usage:

atbridge license status --pretty

Upgrade or wait for the next month’s reset (shown in the same output).

Where to go next

• Try a recipe — pre-built workflows