Connect Microsoft 365 mail to Claude and ChatGPT
Multi Mail connects work and school mailboxes on Microsoft 365 to Claude and ChatGPT with Microsoft sign-in, once your organisation allows it.
For mailboxes Microsoft hosts in Exchange Online - not your organisation's own Exchange server.
The AI apps' own connectors
- Microsoft 365, Anthropic's connector in Claude's directory, connects a work or school account on Claude's Free, Pro, Max, Ultra, Team and Enterprise plans, and Anthropic's help article says it searches its Outlook email beside SharePoint, OneDrive and Teams, and where an admin has enabled write tools drafts and sends mail and manages its categories, inbox rules and automatic replies. Read on 4 November 2026.
- Outlook Email, OpenAI's app for ChatGPT, searches and reads the connected account's mailbox, and reads, moves and sends plain-text email in a shared or delegated mailbox that account can open. Read on 4 November 2026.
- ChatGPT's release notes say that with Gmail or Outlook connected it drafts and sends email from the conversation, sending on the web on Plus, Pro, Business and Enterprise. Read on 4 November 2026.
Connect it
Add it to
- 1Add to ClaudeOpens claude.ai - press Connect there.
- 2
Choose Outlook or Microsoft 365, then sign in with your work address in the window Claude opens. That adds your mailbox and approves Claude in one step.
- 3
Ask Claude about your mail
- 1
Run in Claude Code
/plugin marketplace add lumman-lab/multi-mail/plugin install multi-mail@multi-mailRun the first, then the second.
- 2
Choose Outlook or Microsoft 365, then sign in with your work address on the Lumman page your browser opens. That adds your mailbox and approves Claude Code in one step. If none opens, run /mcp and choose multi-mail.
- 3
Ask, or run
/multi-mail:triage
Works fully on ChatGPT Business, Enterprise and Edu.
- 1
Copy the address
- 2Open ChatGPT plugins
Press +, choose Add custom MCP server, name it Multi Mail, paste the address, choose OAuth, tick the box and press Create as a plugin.
- 3
Install it, then choose Outlook or Microsoft 365, then sign in with your work address on the Lumman page it opens. That adds your mailbox and approves ChatGPT in one step. In a chat, type @ and choose Multi Mail.
- 1
Add to
~/.cursor/mcp.json - 2
Choose Outlook or Microsoft 365, then sign in with your work address on the Lumman page Cursor opens. That adds your mailbox and approves Cursor in one step.
Streamable HTTP, OAuth 2.1 with dynamic client registration. No key or client id.
- VS Code
Run MCP: Add Server, choose HTTP, paste the address and name it multi-mail.
- Gemini CLI
gemini extensions install https://github.com/lumman-lab/multi-mailIts first call opens Lumman's sign-in; /mcp auth multi-mail opens it again.
- Antigravity
agy plugin install https://github.com/lumman-lab/multi-mailRun /mcp, open multi-mail_multi-mail and choose Authenticate; approve on the Lumman page, then paste the code Antigravity shows back into it.
Any number of mailboxes. 25 actions a day free, up to 250 a month, 1,000 a day on Standard for $50 a year or $5 a month, or 10,000 a day on Plus for $200 a year or $20 a month.
Reach and limits
- Search and read it together with every other mailbox you add.
- Draft, reply, forward and send from it.
- Archive, bin and file its mail, and clean up its inbox by sender, putting back what a clean-up moved.
- Set its inbox rules and automatic replies.
If it refuses
- Microsoft needs your organisation's administrator to approve Lumman before this mailbox connects. If you asked for approval on Microsoft's screen, the request is with them and Microsoft emails you their answer; once they approve, connect again.
Connection
- Reached through
- Microsoft Graph
- Permissions
- Mail.ReadWrite, Mail.Send, MailboxSettings.ReadWrite, User.Read, offline_access - delegated
Your data
- Stored
- Microsoft's credential, encrypted under a key held outside the database
- No copy kept - read from the mailbox on each call
- Removing it
- Disconnecting deletes our credential. To remove Lumman at Microsoft too, go to myapplications.microsoft.com.
Tools
- Offered
- All 35
Everything else
Multi Mail's address, sign-in, limits and every tool: Multi Mail's technical details.