Claude works inside Outlook as a Microsoft 365 add-in, so you can triage, summarize, draft replies, and schedule without leaving your inbox or calendar. This guide covers what Claude in Outlook does, how to use it, supported environments, and caveats, based on official documentation. See also the Word and Excel and PowerPoint guides in the same series.
🟢 Model references match the current lineup · model notice · Fable subscription
Fable 5 and 5.1 subscription (updated September 7, 2026): Claude Fable 5.1, released September 1, 2026, is the current Fable model and Fable 5 is now legacy. Plan terms are the same for both — Max and Team Premium plans include Fable at up to 50% of the weekly usage limit; Pro and Team Standard use usage credits (
Common setup
Claude in Outlook is a beta feature on Pro, Max, Team, and Enterprise plans. Install the "Claude for Outlook" add-in from Microsoft AppSource, then open an email in Outlook, click the Claude button in the ribbon, and sign in with your Claude account. Features that span the whole inbox (triage, search, find time) read mail and calendar via Microsoft Graph, so in an organization an IT admin must grant one-time consent (Mail.ReadWrite, Calendars.Read, and others).
Triage your inbox
Ask "what needs me?" and Claude reads your unread mail and attachments, sorting them into three buckets — action items for you (each with a one-line reason), items Claude can handle (scheduling, acknowledgments, standard-form documents, pre-drafted), and noise you archive in one click.
Draft replies in your voice
Tell Claude what to say and it drafts the reply, reply-all, or forward into Outlook's compose pane, unsent. Tone is learned from your sent folder, matching sentence length, sign-off, and formality. It distinguishes reply from reply-all deliberately and warns before adding anyone who wasn't on the thread.
Summarize long threads
Claude reads the whole conversation (every reply and forward) and tells you what's decided, what's open, and who owes what. Every claim cites the source email, and clicking a citation opens that message in Outlook.
Read attachments inline
Claude reads .docx, .xlsx, .pptx, and .pdf attachments on the open email without opening them (including tracked changes in Word). Ask what changed in an attached LOI or what the attached deck argues.
Search, find time, and prep
Find past conversations by topic rather than keywords (with clickable citations), check attendees' free/busy to propose meeting times drafted into Outlook's appointment form, and get a one-page brief of recent threads and attachments before your next meeting.
Working across Office apps
Claude in Outlook shares context with Word, Excel, and PowerPoint. For example, open an attached LOI in Word with the email thread already loaded, or pull numbers from an email into an open Excel model — without copying and pasting between apps.
Supported environments and caveats
It runs on Outlook on the web, Windows (new and classic, Microsoft 365 subscription), and Mac. iOS, Android, Outlook 2016/2019, and on-premises Exchange are not supported. Importantly, Claude never sends mail or invites on its own — every draft lands unsent for you to review and send (it does not request Mail.Send permission in beta). Treat email from external or untrusted senders with caution: bodies and attachments are untrusted input that may hide malicious instructions (prompt injection), so review every draft and inbox action.
Related articles
- Claude in Outlook Guide: Inbox Triage, Voice Replies, Security
- How to Write Prompts for Claude: 6 Core Principles from the Official Docs
- What Is Claude Cowork? Claude's File-Working Desktop Mode
- What Is Claude Design? Anthropic's Chat-to-Canvas Design Tool
- Claude Memory — How to Make Claude Remember and Manage It
- Answering Customer Inquiries with Claude — Support Drafts, Tone, and FAQs