Claude for Outlook (2026): There Are Two of Them, and Only One Runs in Your Inbox

The short answer

There are two different Anthropic products with a claim on your Outlook mailbox, and almost every article about this describes them as one thing. Claude for Outlook is an add-in that runs inside Outlook: it reads the message you have open, drafts a reply into the compose pane unsent, checks attendee availability to book meetings, and triages unread mail. Microsoft's marketplace listing says it is "currently in beta on all paid Claude plans." The Microsoft 365 connector runs the opposite direction — it lives inside Claude and searches your mail, calendar, SharePoint, OneDrive and Teams together — and it requires a work Microsoft 365 account, which means the @outlook.com address most people type into the search box cannot use it. Every fact below comes from Microsoft's catalogue and Anthropic's own pricing page and help center, read September 21, 2026.

What Anthropic actually ships for Microsoft 365

Search Microsoft's marketplace for Claude and you get a long list, most of it third-party tools that call the Claude API and bill their own subscription. Filter to the listings Anthropic publishes itself — the older ones under Anthropic, the newest under Claude by Anthropic for Office, which is a naming split worth knowing about because it is why a publisher-name filter can miss the Outlook one — and the picture gets simple:

Read the last two rows together and the confusion most articles inherit resolves. Outlook appears twice, and the two appearances are opposite products. The add-in puts Claude inside your inbox. The connector is not an add-in at all — it is a data connection pointing the other way, so that Claude can read your mail while you sit in Claude. The umbrella listing is older than the Outlook one and still spells its set out as "Excel, PowerPoint, and Word," which is the single best explanation for why so much of the web still says an Outlook add-in does not exist.

The add-in is in beta, and the beta gate is looser than the others

This is the detail worth the read, because it is the opposite of what you would guess. Each of the three older add-ins carries the same availability sentence in its listing: "Claude for Word is currently available to customers on the Claude Pro, Max, Team and Enterprise plans," and the same for Excel and PowerPoint. The umbrella Claude for Microsoft 365 listing goes further and says it is "generally available on all paid Claude plans."

The Outlook listing says something different: "Currently in beta on all paid Claude plans." So the newest, least finished surface has the widest plan access, and Anthropic's own pricing page backs that up with a dedicated feature row — "Claude for Microsoft Outlook," listed separately from "Claude for Microsoft 365," marked No on Free and Yes on Pro, Max 5x, Max 20x, and on both Team seat types and Enterprise.

Two more places Anthropic treats Outlook as a first-class Office surface rather than a connector afterthought. Its compliance documentation says coverage for "the Claude for Microsoft 365 add-ins (Excel, Word, PowerPoint, and Outlook)" is available in beta. And its Office agent telemetry schema enumerates exactly four surfaces — sheet (Excel), doc (Word), slide (PowerPoint) and mail (Outlook) — with the note that mail carries "no surface-specific attributes or events beyond the common schema." A product that has its own telemetry surface and its own compliance line is shipped, not planned.

What it actually does, from the listing verbatim: it reads the message you have open, full thread and attachments included, and drafts a reply that "lands unsent in Outlook's compose pane, with recipients, subject, and body filled in." It checks availability across attendees to schedule meetings. It triages unread mail. And the sentence that should settle most nervousness about pointing an agent at a mailbox: "Every draft and calendar invite waits for you to click Send."

Note the asymmetry with the connector's write tools, because it is easy to conflate them. The add-in reads attachments on the thread you are looking at. The connector, covered below, cannot attach a file to anything it writes. Same vendor, same mailbox, opposite constraint, and which one bites you depends entirely on which product you installed.

One competitive note, since it is the comparison everyone makes: OpenAI's own Office add-in listing reads "Bring ChatGPT directly into Excel, Word, and PowerPoint. Made by OpenAI." Three apps, one add-in, no email. Outlook is currently a surface Anthropic has and OpenAI does not.

The connector requirement that disqualifies most people searching for this

Everything from here down is about the connector, not the add-in, and the distinction matters most on this first point. Here is the line from Anthropic's help center, quoted rather than paraphrased because it is the reason so many setups fail in the first minute: you need a work Microsoft 365 account tied to a Microsoft Entra tenant, and "Personal Microsoft accounts (such as @outlook.com, @hotmail.com, or @live.com) can't be used."

Sit with that. The address most people type when they search for Claude for Outlook is precisely the address the connector refuses. If your business email is an @outlook.com address, no Claude plan fixes this, because the block is on the Microsoft side of the handshake, not the Anthropic side. The fix is a Microsoft 365 Business subscription with your own domain — which is a thing worth doing anyway, and not because of Claude.

Two more gates sit behind that one. A Microsoft Entra Global Administrator has to grant a one-time tenant-wide consent before anyone in the organization can connect. And if you are on a Claude Team or Enterprise plan, your Claude organization Owner has to enable Microsoft 365 in organization settings as well. In a five-person company those are often the same person and it takes four minutes. In a company with outsourced IT, it is a ticket, and it is worth raising before you promise anyone a demo. If you are still working out which Claude plan a small team should be on before any of this matters, the seat math is on the Claude Team plan.

What the connector can actually do with your mail

Read access is the default and it is on every plan — Free, Pro, Max, Team and Enterprise. Anthropic's own example prompts show the shape it is built for:

• "Summarize email conversations about the product launch."
• "Find emails from the last week about the Q4 budget."
• "Review meeting notes from last week's leadership sync."
• "Draft a reply to the latest email from the vendor, but don't send it."

Notice none of those are "make this email shorter." The connector earns its keep on questions that span a mailbox, a calendar, a SharePoint library and a Teams channel at once, because it has all four connected in the same conversation. That is a genuinely different job from the one an in-window assistant does — including Anthropic's own Outlook add-in, which is why the two are worth installing for different reasons rather than treating one as the other's replacement.

Write access is separate and admin-controlled. With write tools enabled, Claude can draft and send email, manage categories, inbox rules and automatic replies, create and update calendar events, write files to OneDrive and SharePoint, and post in Teams. Three things to know before you design a process around it:

1. Sent mail is labelled. Anthropic says email Claude sends "includes a message header identifying it as agent-initiated." Teams messages, file writes and calendar writes are not currently tagged. If your worry was silently agent-written mail going out under your name, the header is the answer — and if your hope was silently agent-written mail, it is the problem.
2. No attachments. At all. "Attachments aren't currently supported in write tools" — Claude cannot send, forward, or even draft an email with a file attached. Any workflow that ends in "and attach the proposal" is dead on arrival today.
3. Write tools are "subject to per-user limits." Anthropic does not publish that limit as a number anywhere I can find, so nobody outside Anthropic can tell you how many emails a day is too many. Treat the first week as measurement rather than planning around a figure you read on a blog.

Four gotchas the setup guides leave out

The Online Archive is invisible. Claude searches every folder in your primary mailbox, including its Archive folder. It does not search the separate Online Archive, also called the In-Place Archive. In any business with a retention policy, that is the half of your mail history that has already been moved out — and the failure is silent. Claude will not say "there are older messages I cannot see." It will simply answer from what it can reach.

Shared mailboxes do work. If you have delegate access — full access or folder-level, such as seeing only someone's inbox — Claude can search it. For an owner who lives in info@ and sales@, that is the feature that makes this useful rather than a toy.

You cannot scope it to one SharePoint site. Anthropic states that Sites.Selected is not supported, so the connector searches across everything you already have permission to reach. It never exceeds your own permissions, but it also cannot be narrowed below them. If your answer to a compliance question was "we will point it at one library," that answer is not available.

OneNote is unreadable. Notebooks show up in search results because they are ordinary files, then fail to open with a mime-type error. Export to Word or PDF if that is where your SOPs live. The same read logic covers Word, Excel and PowerPoint files, PDFs and plain text; anything else in a library is visible but unopenable. Excel gets the fuller treatment through its own add-in, which is a different product with a different job — that is Claude for Excel.

What to do this week

1. Decide which of the two you actually want, because the account rule only binds one of them. If you want Claude drafting replies in the Outlook window, that is the add-in: install it from Microsoft's marketplace on any paid Claude plan and accept that it is beta. If you want Claude answering questions across mail, calendar, SharePoint and Teams at once, that is the connector, and the next step is the account check.
2. For the connector, check the account before anything else. If your mail is on @outlook.com, @hotmail.com or @live.com, stop here — no configuration will make the connector work, and the real project is moving to a business tenant on your own domain.
3. Ask your admin for the two consents in one message. Entra tenant-wide consent, and on Team or Enterprise, the Claude org setting. Asking for both at once saves a round trip.
4. Turn tools off selectively rather than leaving everything on. Under Customize → Connectors → Microsoft 365, you can keep document search on and switch email access off, per tool. For a first month, read-only with write tools disabled is the honest default.
5. Run one real question, not a test question. "Summarize every thread with this client since June and list what we owe them." If that lands, you know what the connector is for. If it misses things, check the Online Archive before you blame the model.

The document add-in is the more mature sibling and has a different setup with different limits: that is Claude for Word, which is still listed as beta in Anthropic's own feature table while Excel has gone generally available. For the whole picture — which plan, what the connector reads, how it sits next to Copilot — start at Claude for Microsoft 365.

And if what you actually want is somebody to decide which assistant your business standardizes on, which data never goes into any of them, and what the first three workflows should be, that is the AI Readiness Assessment: $2,500 flat, two weeks, credited in full against an install within 90 days. Connecting Claude to a mailbox takes four minutes. Knowing whether you should is the part people get wrong.