MCP server
Outlook MCP server: your Microsoft 365 email and calendar in Claude and ChatGPT
With the Kasar MCP server (https://platform.kasar.app/api/mcp/mcp), Claude or ChatGPT reads your Outlook mailbox live, saves drafts, sends after confirmation and manages your Outlook calendar, Teams links included. The Microsoft account is linked once in Kasar; no Copilot licence is required.
Facts checked on October 6, 2026
01What the assistant does in Outlook
The assistant browses your Outlook folders, including the ones you created, filters unread mail and opens a full thread. It writes a reply into your Drafts, or sends it from your address once you approve the preview. It also reads your Outlook calendar, suggests a slot, creates the meeting with a Teams link and records it in the CRM. All of it with your account and your role in Kasar.
Read a folder, a thread, unread mail
- Tool
- crm_mailbox
- What happens
- Live read at Microsoft. A custom folder is addressed by its Outlook id.
Prepare a reply
- Tool
- crm_draft
- What happens
- The draft lands in the Outlook Drafts folder, unsent.
Send
- Tool
- crm_send_message
- What happens
- Preview, then send after your go-ahead, from the chosen account.
Schedule a meeting
- Tool
- crm_calendar
- What happens
- Created in the account’s primary calendar, guests notified, optional Teams link, after preview.
Record a meeting in the CRM
- Tool
- crm_calendar
- What happens
- The event becomes a CRM meeting, without notifying guests.
Add a correspondent to the CRM
- Tool
- crm_sync_participant
- What happens
- Record created or matched, thread linked, history imported.
Set what enters the CRM
- Tool
- crm_manage_integrations
- What happens
- Sync mode, excluded addresses, domains and subjects.
02Connecting Outlook to Kasar, and the locked tenant case
The Microsoft account is linked in Kasar, not in the chat: Settings, Channels, Outlook tile, then authorisation at Microsoft. Kasar asks for mail read and write, send, profile, and calendar read and write. Linking the mailbox therefore links the Outlook calendar as well.
Many Microsoft 365 organisations stop users from authorising apps themselves. Authorisation then fails with “Need admin approval” until a directory administrator approves Kasar once for the whole organisation. They need no Kasar account. The Microsoft 365 admin consent guide lists the permissions and the three ways to grant them.
03Add the Kasar connector to ChatGPT
- 1
Create the app
An admin first turns on ChatGPT developer mode. Then, under Apps, Create, paste the URL above and choose OAuth authentication.
- 2
Pick the workspaces
Kasar shows its consent page. Tick the workspaces ChatGPT may reach, choose the default one, then Authorize. Declining creates nothing.
- 3
Run a first read
Ask “list my Outlook folders”. If the mailbox is not linked in Kasar yet, the assistant tells you where to do it.
ChatGPT connects to Kasar with OAuth 2.1 and PKCE. The token is valid for 90 days, appears in your keys under the client’s name and is revoked like a key; when it expires, the client asks for authorisation again. The same URL works for Claude as a custom connector. On the ChatGPT side, sending, drafts, meetings and other write actions need full MCP, in beta for Business, Enterprise and Edu plans, on the web, as of 6 October 2026; on Pro, ChatGPT reads only. The full walkthrough, Claude’s Microsoft 365 connector included, is in the Claude and Outlook tutorial.
04Five prompts to copy
- 1
“In my Tenders folder, which unread emails arrived this week?”
crm_mailbox lists your folders, finds the custom folder id, then filters its unread threads.
- 2
“Offer Sophie three slots next week and draft the email, but don’t send it.”
crm_calendar reads your events over the period, the assistant spots the gaps, crm_draft drops the proposal into your Outlook Drafts.
- 3
“Book Thursday 2 pm with Marc, with a Teams link.”
crm_calendar returns a preview of the event and the guests to be notified; creation follows your confirmation.
- 4
“Yesterday’s meeting with Lumen is missing from the CRM: log it on the record.”
crm_calendar records the event as a CRM meeting, after a preview, without sending anything to guests.
- 5
“Reply to procurement’s chaser that the quote goes out on Friday.”
crm_send_message previews from your Outlook address, then sends with the confirmation token.
05Sends and calendar changes go through a preview
Sending an email, creating, moving or deleting a meeting all reach real people. Each goes through a preview, then a single-use confirmation token valid for 5 minutes and bound to the exact operation. Change the time or a guest after the preview and the token is refused; the assistant previews again. A draft never leaves on its own.
The server also drops duplicate sends repeated within a short window and caps sends at 30 per hour per user. Addresses on your workspace suppression list receive nothing, and the response says so.
An email and an invitation carry your name: the assistant prepares them, you sign them.
06What about Microsoft’s own MCP server?
Microsoft publishes an MCP server for mail, Work IQ Mail, whose tools read, search, send, reply to and delete messages. As of 6 October 2026 it is in preview, requires a Microsoft 365 Copilot licence and is connected from the Microsoft 365 admin center, Microsoft Copilot Studio or Microsoft Foundry, under the tenant administrator’s control.
Kasar targets another use: a salesperson working in Claude or ChatGPT who wants the email, the calendar, the client record and the deal to answer together. The Outlook mailbox is included from the Free plan (one email and calendar account), two mailboxes on Pro, and the MCP server comes with every plan: see pricing.
For Outlook inside Kasar without an assistant, read the Outlook integration page. Tool parameters are in the messaging tools reference.
Frequently asked questions
No. Kasar connects to your Outlook mailbox with the usual Microsoft authorisation, and the assistant goes through the Kasar server. The Copilot licence applies to Microsoft’s Work IQ server, not to Kasar.
Only if your organisation stops users from authorising apps. In that case a directory administrator approves Kasar once for the whole organisation, without creating a Kasar account. The admin consent guide walks through it.
Yes. When it creates an event in your Outlook calendar it can add a Teams video link. Creation goes through a preview listing the guests, then your confirmation, since guests receive the invitation.
Kasar can connect an Exchange mailbox, but the assistant’s calendar tool covers Google and Microsoft calendars, not Exchange. Meetings from an Exchange calendar are logged in the CRM from the Calendar page of the app.
Sources
Every fact on this page can be checked on the official page below, read on the date shown.
- OpenAI, aide : Developer mode and MCP apps in ChatGPT · read on October 6, 2026
- Microsoft Learn, Work IQ MCP overview (preview) · read on October 6, 2026
- Microsoft Learn, Mail reference (preview) · read on October 6, 2026
- Kasar, documentation : outils MCP de messagerie · read on October 6, 2026