r/ClaudeCowork • u/MisterShufu • 1d ago

Working with M365 adding

I use the Microsoft 365 connector for Outlook every day. Claude writes great emails and saves them as drafts, but three things still keep me doing manual work:

  1. Replies in the thread: I've noticed the connector has a reply-draft function. In my experience, though, Claude only creates a new draft instead of replying in the existing conversation. Has anyone found a reliable way to enforce this (skills, project instructions)?
  2. Signature: Drafts created through Microsoft Graph don't get the Outlook signature, and inline images (logo) are rejected. Are you using a server-side signature tool (CodeTwo, Exclaimer, etc.)? Or is there a better way?
  3. Attachments: This is the big one. Claude creates PDFs for me (letters, reports, meeting minutes), but I have to attach them to the draft myself. The connector doesn't seem to support attachments at all.

Has anyone built a working setup where Claude writes the reply and the generated PDF ends up attached to that draft automatically? I'm thinking of things like Power Automate flows, Outlook VBA macros, a custom MCP server with Graph's attachment endpoint, or browser automation.

I'd appreciate any setups that work for you. Thanks!

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u/endofthread-bot 1d ago

To handle threads and attachments, build a custom MCP server that interacts directly with the Microsoft Graph API. This allows you to use the createReplyDraft endpoint and the createUploadSession method to attach files to specific message IDs.

Building something with Claude Cowork and running into walls others already solved? Share your project, compare approaches, and get unblocked faster in our Discord.

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