Set-up guide
Connect Claude to Outlook in one sign-in.
Can Claude use Outlook? Yes, and so can ChatGPT or any other MCP client, once the mailbox is connected here. Outlook and Microsoft 365 mailboxes can't be opened with a password any more, and that isn't a limitation of this product. Here's what does connect them, and why it takes one screen rather than 20.
- Time About 2 minutes
- You will need Your Microsoft sign-in
- Admin consent Usually not required
The short version
Sign in to the control panel, choose Add mailbox, pick Microsoft 365, sign in with Microsoft, and accept the permissions. That's the whole thing.
If you've connected a Gmail mailbox before and are looking for the app password step, there isn't one.
Work or school account, or a personal Outlook.com or Hotmail one? This page is for work and school. For a personal account, connect Claude to Hotmail or Outlook.com instead.
Before you start
What you need to connect Outlook to Claude or ChatGPT
Shorter than you're expecting, and 3 of the 6 rows are things other guides will tell you to do that you can skip.
- A Microsoft 365 mailbox work or school account
- Your Microsoft sign-in password + MFA as usual
- An app registration of your own not needed
- Authenticated SMTP switched on not needed
- Your IT administrator usually not needed
- Time to allow about 2 minutes
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You don't register an application.
Most Microsoft 365 connection guides walk you through creating your own app registration in Entra: names, redirect URIs, API permissions, client secrets. You don't need to do any of that.
One registration serves every Mailbox MCP customer. So there's no client ID for you to copy, and no secret for you to store and later have expire.
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A personal Outlook.com or Hotmail address takes the same sign-in.
The rows above describe the work or school case, because that's where the traps are.
A personal account has one switch to turn on first, and its own guide shows where it is.
Outlook.com and Hotmail
A personal Outlook.com or Hotmail mailbox has its own guide
This page is for work and school accounts. An address ending @outlook.com, @hotmail.com, @live.com or @msn.com is a personal Microsoft account, and Outlook.com keeps apps out of it until you turn on one setting.
In short: at outlook.live.com open Settings, Mail, Forwarding and IMAP, turn on Let devices and apps use IMAP, save, and connect again. Connect Claude to Hotmail or Outlook.com has the picture, what "User is authenticated but not connected" means, and what a personal account can and can't do.
Walkthrough
Connect Outlook to Claude or ChatGPT, step by step
5 steps, a few minutes. Step 2 is the one that catches people out.
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Add a mailbox in the control panel
Sign in to Mailbox MCP, choose Add mailbox, and pick Outlook, Hotmail or Microsoft 365. You're sent to Microsoft to sign in.
Nothing has been connected yet, and nothing is stored until you finish.
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Choose your work or school account
If Microsoft asks which account you mean, choose Work or school account.
The trap that catches people
The same address can exist twice: once as your Microsoft 365 work account, and once as a personal Microsoft account someone created years ago. They're different mailboxes.
Picking the personal one completes successfully, connects an empty or unfamiliar mailbox, and gives you no error to search for. If the mail Claude reports isn't the mail you expect, this is almost always why.
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Review the permissions and accept
Microsoft shows you exactly what's being asked for. Read it: you should read every one of these, and knowing what a correct prompt looks like is how you recognise a suspicious one. The next section lists each permission and what it's for.
The screen names BSolve IT Limited, which is the company behind Mailbox MCP. A company name you weren't expecting is a good reason to stop; this one is correct.
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Add the connector to Claude or ChatGPT
In Claude: open Mailbox MCP in Claude's directory (or Customize, then Connectors, and search for it) and press Connect to Claude. Sign in to Mailbox MCP when it asks, and choose your Outlook mailbox.
Want one connector per mailbox, or no directory in your organisation? Add a custom connector: Customize, Connectors, + Add, Add custom connector. Give it a name, paste the connector URL from the mailbox's Connector tab in the control panel and press Continue, then Add without changing anything. Then press Connect and choose your Outlook mailbox. The Claude.ai set-up guide has every screen.
Claude starts a new connector's tools at Needs approval, so it asks before every step. We set ours to Always allow (open the connector under Customize, Connectors) and let the level you chose in the control panel be the limit.
In ChatGPT: select Plugins in the sidebar, find Mailbox MCP in the plugin directory, select Install plugin, then Continue to Mailbox MCP, and sign in. For a second mailbox, open the plugin again and press Connect another account. The ChatGPT set-up page covers developer mode too.
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Check it from Claude or ChatGPT
Start a new chat and ask: Using Mailbox MCP, list my 5 most recent emails. If they're the messages you expect, the mailbox is connected, and reading it hasn't marked anything as read.
Which one
Claude for Outlook, Claude's Microsoft 365 connector, ChatGPT's Outlook app, or this
"Claude for Outlook" means 3 different things in search results. Here's which is which, in the vendors' own words, and where this Outlook MCP server fits.
| Claude for Outlook add-in | Claude's Microsoft 365 connector | ChatGPT's Outlook app | Mailbox MCP | |
|---|---|---|---|---|
| Where it works | Inside Outlook, on the message you have open | In Claude | In ChatGPT | In Claude, ChatGPT or any MCP client |
| Which mailboxes | "Exchange Online through Microsoft 365 is required" | Work or school; personal accounts "can't be used to connect" | Microsoft accounts; personal ones not stated | Work, school and personal Microsoft accounts |
| Claude or ChatGPT plan | Pro, Max, Team and Enterprise, "currently in beta" | "All Claude plans" | Sending on Plus, Pro, Business and Enterprise | Any plan, Free or Pro here |
| Sends email | "Claude never sends mail or invites on its own" | Yes, once an administrator enables writes | A draft you choose to send | Yes, at the level you set, filed in Sent once |
| Reads what's inside an attachment | .docx and .xlsx inline; PDF not yet | Not stated | Retrieves your own mailbox's attachments, not shared ones | PDF, Word, Excel, text and pictures |
The difference is scope. The add-in works on the one message in front of you; Mailbox MCP lets your AI work the whole mailbox from a chat. Vendor cells were read on 4 and 5 October 2026 from the pages under Sources. "Not stated" means the page says neither yes nor no.
How the free Gmail and Outlook connectors compare goes through it job by job, and a personal account has its own guide: connect a personal Outlook.com or Hotmail account.
Permissions
What the permission screen asks for, and why
6 permissions, and this is the complete list. A consent screen that asks for more than it needs is worth refusing. That only means something if the list you were given beforehand was exact, so here's every one, with what it's actually for.
| Permission | What it lets us do | Why it is needed |
|---|---|---|
IMAP.AccessAsUser.All |
Read and write the mail in your mailbox | Listing, searching and reading messages, moving them between folders, and flagging them |
Mail.Send |
Send mail as you | Sending and replying. Not Mail.Send.Shared: we send as the mailbox owner and never on behalf of anyone else |
Calendars.ReadWrite.Shared |
Read and write your calendar, and calendars shared with you | Every calendar tool. The .Shared ending is what lets it read a colleague's diary they have already shared with you; it does not widen what you are allowed to see, because Microsoft decides that and we ask with your own account's rights |
MailboxSettings.ReadWrite |
Read and change your mailbox settings | Your timezone and working hours, without which a time cannot be stated or a free slot judged, and your out-of-office reply, which is a mailbox setting rather than a calendar entry |
Contacts.ReadWrite |
Read and write your own contacts | Every contact tool: looking a person up, opening a card, adding, correcting and deleting one, and importing a contacts file, in your own Contacts folder and your own contact folders. ReadWrite because cards are written as well as read; not the shared form, so a folder somebody else shared with you is not reached |
offline_access |
Keep access after you close the browser | Without it the connection would expire in about an hour and you would be signing in again all day |
None of these needs an administrator to approve it in a normal tenant, which is what makes this a 2 minute job rather than a support ticket.
Connected before 2 September 2026?
Then you weren't asked for the 2 calendar permissions, and Microsoft doesn't widen a permission you've already given. Your mail keeps working exactly as it did.
The calendar tools appear once you reconnect the mailbox and approve the longer list. The control panel offers that on the mailbox's connection tab, and describes it as an offer rather than a fault, because it is one.
The first 3 permissions were counted off the real screen on 30 August 2026. The 2 calendar permissions joined the request on 2 September 2026 and were approved on a real Microsoft tenant the same day, and the contacts permission joined on 17 September 2026.
Troubleshooting
If Outlook won't connect
5 things that go wrong, and the fix for each.
Microsoft says approval is required
Some organisations don't let staff consent to applications themselves. If you see a message about needing approval or an administrator, your tenant has that setting switched on. An administrator has to approve Mailbox MCP once for your organisation, and after that everyone connects normally.
Send them the page written for Microsoft 365 administrators. It carries the app's identifiers, the permissions in the table above and nothing else, and the link that approves it for everyone in one step.
Microsoft granted permission, but the mailbox could not be opened
On a personal Outlook.com, Hotmail, Live or MSN address, this is the IMAP switch nine times in ten. The Outlook.com guide shows where it is, and the connection works the moment it's on.
The tenth time, the Microsoft account you signed in as isn't the one that owns the address you typed. Sign out of Microsoft in the browser and connect again as that address.
On a work or school account this message is rare. The mailbox's Connection tab in the control panel names the step that refused, in Microsoft's own words. Email that line to support@mailbox-mcp.com and a person looks at it.
The mail Claude sees is not your mail
You've almost certainly connected a personal Microsoft account with the same address, rather than the work or school one. Remove the mailbox in the control panel and add it again, choosing Work or school account at the chooser.
The publisher on the consent screen is a different name
Microsoft shows the verified publisher rather than the product, and the verified publisher has to be the company as it appears on the public register. So the screen reads BSolve IT Limited, company 04607330, registered in England and Wales. Mailbox MCP is what that company builds.
The blue tick beside the name is Microsoft saying it checked the business behind the app, which it did on 30 August 2026. A screen with no tick, or the words not verified, would be worth pausing on. This one is the opposite of that.
Folder names look wrong
Exchange calls them Sent Items, Deleted Items
and Junk Email, where most other providers use Sent, Trash
and Junk. Nothing is misconfigured: ask for the folder by the name
Outlook shows you, and it will be found.
Mechanics
Why your Outlook password won't work
On 1 October 2022 Microsoft disabled Basic Authentication for IMAP in Exchange Online. From that date, a username and password stopped being able to open a Microsoft 365 mailbox at all: for every mail client, everywhere, at once.
This catches people out because it doesn't feel like a policy change. It feels like a broken setting. You know the password's right, you can sign in to Outlook with it, and yet the connection is refused.
So the natural assumption is that something is misconfigured, and people go looking for a switch that no longer exists.
There is no switch. The replacement is OAuth: you sign in to Microsoft directly, Microsoft asks whether you agree to let Mailbox MCP use your mailbox, and Mailbox MCP receives a token instead of a password.
Your password is never typed into this site and never reaches us.
Worth knowing
This is also why any tool that asks for your Microsoft password to read your mail can't do what it claims for a Microsoft 365 mailbox. It's describing how mail worked before October 2022.
Sending
Why you do not need Authenticated SMTP
This is the step that stops most Microsoft 365 integrations, and you can skip it entirely.
Microsoft turns off SMTP AUTH by default for tenants created after 2020, because it's a password-spray target. So any tool that sends your mail over SMTP needs somebody to switch Authenticated SMTP back on for your mailbox in the Microsoft 365 admin centre.
That usually means asking IT, and plenty of security teams say no on principle, having turned it off deliberately.
Mailbox MCP sends through Microsoft Graph instead. Graph needs no tenant setting changed, files the copy in your Sent Items itself, and keeps the thread intact. So there's nothing to enable, nobody to ask, and one fewer reason for the connection to half-work.
If you've seen this error while trying to make something else work:
535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Tenant.
That's the wall. It's a tenant policy rather than a bug or a permissions mistake, and it isn't something you'll meet here, because we don't use that path.
The diary
Your Outlook calendar comes with the same sign-in
You approve once, and the mailbox arrives with its diary already attached. 2 of the 6 permissions above are the calendar ones, on the same screen as the mail ones.
There's no second account, no second connector in your AI client, no CalDAV address to go and find, and nothing extra to pay. Microsoft 365 is the provider where every part of this works, because Graph is one API over both.
What that actually gets you
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Read and search the diary.
Read the week and search it by subject, location or organiser. Open one event with everybody invited and how each of them answered.
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Find a time that suits everybody.
Ask when a group of people are free. Or ask Microsoft directly for ranked times a meeting would fit, honouring everybody's working hours and each person's answer to whether they're needed.
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Book your time, and meet.
Block your own time, move it, repeat it. Invite people, add a Teams link, reschedule and tell everybody, or cancel with a message.
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Answer an invitation properly.
Accept, tentative or decline, with a note to the organiser if you want one.
Or decline and propose a different time in the same action: the answer a person actually wants to give, and one most integrations can't express at all.
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Reminders and categories.
Snooze a reminder or dismiss it. File an event under the same categories, and the same colours, you already use in Outlook.
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And the out-of-office, which isn't a diary entry at all.
Read your automatic reply as it stands, set it for a date range with a different message for people outside your organisation, or turn it off.
It's the same setting Outlook writes, so it shows up in Outlook, and it switches itself off at the end of the period exactly as one you set by hand would. That's what the mailbox settings permission is for: the one thing here that lives on the mailbox rather than in the diary.
What still says Microsoft only
A calendar on any other provider connects one of 2 other ways: a Google sign-in for a Google diary, or a CalDAV address for anything else. These 3 things are Microsoft 365 and nothing else, on either of those routes.
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The structured counter-proposal.
Declining and suggesting another time is one action, and the organiser's Outlook understands it.
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The ranked meeting suggestions.
They're Microsoft's own answer, rather than a search we run.
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The out-of-office.
It's a mailbox setting rather than a diary entry, and neither CalDAV nor Google Calendar has an equivalent of it.
The address book
Your Outlook contacts come with it too
Approve once, and the people in Outlook are the people your assistant can find, open and keep right.
A Microsoft 365 mailbox brings its Outlook contacts with the mail, on the same sign-in, so there is no address to give and nothing to connect.
The contacts permission in the table above is what carries them, and it's on the same screen as the rest. On a Gmail or IMAP mailbox an address book is a Google sign-in of its own or a CardDAV address you go and find. Here there's no address, because Microsoft Graph reaches the contacts the same way it reaches the diary.
What appears on the connector
The same contact tools a connected CardDAV book gets, and on this route always all of them, because Microsoft has no per-folder rights on your own contacts.
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Find a person.
find_contact, which every mailbox has, reads your Outlook contacts beside the mailbox's own history from then on.It ranks a person from the book first, with every address, the phone numbers, the postal addresses with their postcodes, the employer and the job title.
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Open, add, correct and import.
read_contactopens one card in full,create_contactadds one,update_contactcorrects one, andimport_contactsbrings a vCard export in.The add, the correction and the import sit at Draft and file.
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Delete, and be asked first.
delete_contactremoves one for good. It sits at Send and delete, beside deleting a message, and a compliant AI client stops and asks first, naming the person. -
What a card carries.
Every name, every email address with its type, every phone number with its type, the postal addresses with their type (home, work or other), each with street, town, county or region, postcode and country, the employer, the job title and the note.
On Outlook, one postal address of each type, home, work and other, and an untyped one is filed as other.
The tool reference has each one with what it refuses.
What is never stored
Nothing beyond the Microsoft grant the mailbox already had. A card is fetched from Microsoft to answer the question asked, held in memory for about 10 minutes, and forgotten.
A card you ask the assistant to add or correct is written to your Outlook contacts, where your phone and Outlook see it, and to nothing of ours. No table, no file, no log line and no audit row carries a name, an address or a phone number.
A contact's photo is never requested on Outlook contacts, on a look-up or a correction. The privacy policy states the same in its own words.
What reads differently from a CardDAV book
- The books are the default Contacts folder, the user's own top-level contact folders and their child folders one level deep, at most 30 in all, every one writable; a folder nested deeper, or shared or delegated by another user, is not among them. The permission covers your own contacts and nothing else.
- An email address on an Outlook contact carries no type (home, work), and a phone number typed as other is filed as a work number, because those are the fields Microsoft offers.
- On Outlook contacts an imported card is skipped where the folder already holds its first email address (Microsoft mints the ids, so there is no card id to land on twice), a card with no email address is added every time, and a group card is not imported. So run a file once.
- On a Microsoft mailbox the fields this server names come across (name, emails, phones, postal addresses, company, job title, note); a birthday, a photo, a web address or the categories in the export do not, and a card with two postal addresses of one type keeps the first of each, since Outlook holds one home, one work and one other address.
Limits
What this connection does not do
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No Exchange shared mailboxes
An Exchange shared or delegated mailbox, the kind with no sign-in of its own that Outlook reaches through Full Access or Send As, cannot be connected. One connection is one mailbox, signed in as its owner.
Sharing a mailbox you own with named people is Team Access, a different thing. A shared calendar does work: one a colleague has shared with you can be read, and written to where they allowed it. A shared contacts folder does not, because the contacts permission covers your own.
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Mail, calendar and contacts, nothing beyond those 3
The permissions above cover mail, the calendar and your own contacts, and nothing else: no files on a drive, and no permission that would reach one. An address book at another server is a route for mailboxes that connect with a password, so it does not attach to this one; the contacts here are the Outlook ones, which need no address.
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20 MB a message
Attachments are capped at 20 MB a message in total, not per file, and the ceiling is ours rather than Microsoft's. A file in your mailbox can use all of it; one the assistant writes itself is far smaller.
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A file the assistant writes itself
Only a file the assistant composes and has to write out itself is small. Files already in the mailbox, at a web address, uploaded through a one-off link, or in a ChatGPT conversation are streamed at send time and never pass through the model.
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Not a backup tool
It is not a backup or an export tool, and it cannot recover mail already deleted at Microsoft.
FAQ
Questions about connecting Outlook to Claude or ChatGPT
How do I connect Claude to Outlook?
In the Mailbox MCP control panel, add a mailbox, choose Outlook, Hotmail or Microsoft 365, sign in with Microsoft and approve the permissions. Then add Mailbox MCP to Claude from its directory under Customize, Connectors, or as a custom connector, and sign in again to pick the mailbox. No password is typed anywhere. On a personal Outlook.com or Hotmail address, turn on IMAP in Outlook's settings first.
How do I connect ChatGPT to Outlook?
Connect the mailbox in the Mailbox MCP control panel with your Microsoft sign-in, then in ChatGPT select Plugins, find Mailbox MCP, choose Install plugin and sign in, picking that mailbox. ChatGPT has its own Outlook app too; type @ and pick Mailbox MCP when you want this one.
Is this the same as the Claude for Outlook add-in?
No. The add-in works inside Outlook on the message you have open, needs Exchange Online through Microsoft 365, and never sends: Anthropic says it lands every draft unsent. This connects your mailbox to Claude, ChatGPT or any MCP client from outside Outlook, works on personal Outlook.com accounts too, and sends through Microsoft Graph at the level you allow.
Why does my Microsoft 365 mailbox reject its password?
Because Microsoft switched off Basic Authentication for IMAP in Exchange Online on 1 October 2022, so a username and password cannot open a Microsoft 365 mailbox at all, in any mail program. Nothing is misconfigured. The replacement is a Microsoft sign-in: you sign in to Microsoft, approve what Mailbox MCP may do, and Mailbox MCP receives a token rather than a password. Your password is never typed into this site and never reaches us.
Do I need my IT administrator to connect a Microsoft 365 mailbox?
Usually not. All 6 permissions the sign-in asks for are delegated, and none of them requires admin consent in Microsoft's own classification, so on Microsoft's default consent setting you approve them yourself. Some organisations do not let staff consent to applications at all. If Microsoft shows a message about needing approval, an administrator approves Mailbox MCP once for everyone, with the link on the page for Microsoft 365 administrators. Then each person connects their own mailbox normally.
Do I need Authenticated SMTP switched on for Microsoft 365?
No. Sending goes through Microsoft Graph rather than SMTP, so the Authenticated SMTP setting Microsoft turns off by default stays off, nobody has to change a tenant setting, and the 535 5.7.139 "SmtpClientAuthentication is disabled for the Tenant" error other tools meet is one you will not see here. Graph files the copy in your Sent Items itself and keeps the thread intact.
Can Claude read and update my Outlook contacts?
Yes. The contacts permission is on the same consent screen as the mail, so there is no address book to connect. Your assistant can find a person, open a card with read_contact, and add, correct, import or delete cards; deleting needs Send and delete, and a compliant AI client asks first. A card is held in memory for about 10 minutes and forgotten, and a change is written to your Outlook contacts and to nothing of ours.
Can I connect a personal outlook.com or hotmail.com account?
Yes, with the same Microsoft sign-in, once you've turned on Let devices and apps use IMAP under Settings, Mail, Forwarding and IMAP in Outlook.com, which keeps it off by default. Watch the chooser too: the same address can exist as a personal and a work account, and connecting the wrong one completes without an error. The Outlook.com guide has the rest.
Attribution
Sources
- Anthropic: Use Claude for Outlook The add-in's plans and beta status, the Exchange Online requirement, that it never sends, and the .docx and .xlsx attachment reading. Read 5 October 2026.
- Anthropic: Set up the Microsoft 365 connector "All Claude plans", the Entra tenant requirement and the refusal of personal accounts. Read 4 October 2026.
- Anthropic: Microsoft 365 connector security guide That an administrator enables the write tools; nothing on reading an attachment's contents, hence Not stated. Read 1 October 2026.
- OpenAI: Outlook Email and Calendar apps in ChatGPT The attachment sentence for shared and delegated mailboxes; nothing on personal accounts, hence Not stated. Read 4 October 2026 in a browser.
- OpenAI: ChatGPT release notes The 8 June 2026 entry: sending from a chat on Plus, Pro, Business and Enterprise, as a draft you choose to send.
- Microsoft Learn: deprecation of Basic authentication in Exchange Online The 1 October 2022 date, and the scope of what was disabled.
- Microsoft Learn: enable or disable authenticated client SMTP submission Why SMTP AUTH is off by default, and what enabling it involves.
- Microsoft Graph: sendMail The send path used instead of SMTP.
- Microsoft Graph: contact resource type The Outlook contact as Graph reads and writes it: the fields a card carries, that contacts live in contact folders, and that the photo is a separate resource the tools never ask for.
Connect an Outlook mailbox.
The free tier is 5 calls a day on any mailbox, which is enough to see whether it does what this page says before you pay anything.