Radmail MCP

What radmail-ai/radmail-mcp MCP server does

radmail-ai/radmail-mcp MCP server exposes an email workflow through Model Context Protocol. Its sandbox can rank supplied messages, identify a short “Right Now” lane, explain why a message was surfaced, extract open commitments, search message fields, and produce reply drafts for review. The hosted sandbox can also triage a built-in demo inbox without credentials.

The server does not expose an email-send tool. Money-related requests, changed banking details, first-contact messages, decisions or sign-offs, and prompt-injection cases are hard-stopped in code and remain human-only. Draft generation is limited to reviewable output and refuses those hard-stopped cases.

How it works

The fastest path is the hosted streamable HTTP endpoint at https://radmail.ai/api/mcp/sandbox. Most sandbox triage calls can omit a token; the service provisions a free sandbox tenant automatically. A caller can also use provision_sandbox explicitly and reuse the returned token.

For local use, radmail-ai/radmail-mcp MCP server runs over stdio from npm with npx -y radmail-mcp. The local surface processes messages supplied to the tools and uses an in-memory sandbox engine. It can also operate in connected mode when RADMAIL_API_KEY is present. In that mode, search, email reading, Right Now results, and commitment lists come from the user’s RadMail inbox through read-only API requests.

Email-derived fields are marked with provenance: "untrusted-email-body". Agents should treat those values as data rather than instructions. Responses also include a safety block describing the hard stops. If connected requests fail because of an invalid key, insufficient entitlement, or timeout, the server returns a typed error instead of fabricating results.

Tools and capabilities

radmail-ai/radmail-mcp MCP server includes these capabilities:

• triage scores one message across importance and urgency, explains the score, extracts dimensions and commitments, and reports hard stops.
• triage_inbox processes a batch and returns the Right Now lane, open commitments, and hard stops in one call.
• list_right_now returns prioritized items and their reasons, using supplied messages or the connected live API.
• why_surfaced explains the signals behind a message’s priority.
• search ranks messages by sender, subject, or content; connected mode also supports sender and date filters.
• read_email retrieves one connected message by ID, including headers and text body.
• list_commitments identifies promises, parties, actions, due information, state, and confidence.
• draft_reply creates a non-sending reply for an eligible commitment.
• check_send_domain reads SPF, DMARC, and common DKIM selector DNS records and returns verdicts, parsed details, and advice.
• report_need, request_capability, and radmail_learning_insights support feedback, capability requests, and transparency about learned usage patterns.

Setup and configuration

Use the hosted endpoint when no installation or credentials are wanted. For a local MCP client, configure the command npx with arguments -y radmail-mcp. Connected inbox operations require a RadMail API key created through the RadMail settings page. Set it as RADMAIL_API_KEY; RADMAIL_API_URL can override the default API host of https://app.radmail.ai.

The repository also documents running from source with npm i, npm run build, and npm start. The hosted server can be deployed as a Vercel Node serverless function using its MCP handler.

Limitations and notes

The local sandbox is heuristic, in-memory, and free; it is not the production live engine. Without an API key, connected-mode calls return setup instructions and sandbox behavior remains available. Connected mode does not send, draft against, or mutate real mail. The domain checker is also read-only and has no mail-sending capability.

The safety model depends on absent capabilities: no send tool exists on the server. Agents should still inspect the machine-readable safety contract before connecting and preserve the taint markings when reasoning over email content.