outlook-mcp

A small, self-hosted MCP server that gives an LLM (Claude Code, Claude Desktop, or any MCP client) read-only access to a personal Outlook.com mailbox (outlook.com / hotmail.com / live.com) through the Microsoft Graph API.

It authenticates against Microsoft's consumer OAuth endpoint (/consumers), which is what lets personal Microsoft accounts sign in. Most "Microsoft 365" connectors are registered as work/school-only apps and will reject a personal account — this one is built specifically for personal mailboxes.

Your data stays local. The server runs on your machine and caches your OAuth token in ~/.outlook-mcp/token.json (file permissions 600). Nothing is sent anywhere except directly to Microsoft Graph.

Tools

All tools are read-only — the app requests only the Mail.Read scope. No send, no delete.

Setup

1. Register your own Azure app (free — no paid subscription needed)

Each user brings their own app registration, so no shared infrastructure or credentials.

1. Go to https://entra.microsoft.com → App registrations → New registration.
2. Name: anything, e.g. Outlook MCP.
3. Supported account types: Personal Microsoft accounts only (or "any org directory and personal Microsoft accounts" if you also use work accounts).
4. Redirect URI: platform Public client/native (mobile & desktop), value: http://localhost:8765/callback
5. Register, then copy the Application (client) ID from the Overview page.
6. Authentication → enable Allow public client flows → Save.
7. API permissions → Add a permission → Microsoft Graph → Delegated → add Mail.Read (also offline_access and User.Read if not auto-added). No admin consent is required for a personal account.

2. Install

With uv (recommended):

# clone, then from the repo root:
uv sync

Or install into any environment with pip:

pip install .

3. Configure and sign in (one time)

# PowerShell
$env:OUTLOOK_MCP_CLIENT_ID = "<your-application-client-id>"
uv run outlook-mcp-auth

# bash / zsh
export OUTLOOK_MCP_CLIENT_ID="<your-application-client-id>"
uv run outlook-mcp-auth

A browser opens; sign in and approve. Your refresh token is cached and auto-renews after that.

4. Register with your MCP client

Claude Code:

claude mcp add --scope user outlook \
  --env OUTLOOK_MCP_CLIENT_ID=<client-id> \
  -- uv --directory /path/to/outlook-mcp run outlook-mcp

Claude Desktop / other clients — add to the MCP config file:

{
  "mcpServers": {
    "outlook": {
      "command": "uv",
      "args": ["--directory", "/path/to/outlook-mcp", "run", "outlook-mcp"],
      "env": { "OUTLOOK_MCP_CLIENT_ID": "<client-id>" }
    }
  }
}

A one-click Desktop Extension bundle (manifest.json) is also included — see Desktop Extension below.

Configuration

Desktop Extension

manifest.json follows the MCP Bundle / Desktop Extension spec. It prompts the user for their client ID on install. To build the installable bundle:

npx @anthropic-ai/mcpb pack

Then open the resulting .mcpb file with Claude Desktop.

Re-authenticating

If the cached token is revoked or expires beyond refresh, just run the sign-in again:

uv run outlook-mcp-auth

Security notes

• Read-only (Mail.Read) — the server cannot send, move, or delete mail.
• Tokens never leave your machine; ~/.outlook-mcp/token.json is excluded from git.
• Each user uses their own Azure app registration, so there is no shared client secret.

License

MIT — see LICENSE.