How to Connect Multiple Outlook Calendars to Claude Cowork
Claude Cowork holds one Microsoft identity, will not book on any calendar that is not your own, and cannot connect a personal Outlook.com address at all. Connect every Microsoft account to Carly, add Carly to Claude once, and a single Cowork task can read or book on whichever calendar you name. Carly holds your Google calendars and every mailbox on both sides in the same place, so this setup covers the rest of what you own.
1. Add your Outlook calendars to Carly
- Sign in at carlyassistant.com.
- Open carlyassistant.com/integrations.
- Find Outlook Calendar, click Connect, and authorize the calendar.
- Click Connect again for the next one, and keep going for as many calendars as you want.
Unlimited connected calendars are included, so a second or third Microsoft account is not a per-account charge.
Carly connects to thousands of apps, so while you are on that page you can add your inboxes, files, CRM, and anything else you want Claude Cowork to reach through the same connector.
2. Connect Carly to Claude Cowork
In Claude:
- Open Customize in the sidebar.
- Select Connectors.
- Click +, then Add custom connector.
- Paste
https://carlyassistant.com/mcp/. - Click Add and authorize your Carly account.
- In the Cowork task, open + → Connectors and enable Carly.
Anthropic documents this path in its remote MCP connector guide. Connectors sync at session start, so a connection added mid-session may need a fresh one.
What the finished setup gives you
With one Carly connector in Cowork, you can:
- compare a work calendar and a personal one in the same question;
- book on the account that owns the meeting;
- put an event on a calendar a colleague shared with you;
- hold a client tenant alongside your own without either dropping off;
- clear a room and an executive’s diary in one pass;
- keep it running when an invite lands and nobody is watching.
The accounts stay separate underneath. Carly supplies the routing, and Claude remains where you run the task.
Why the native Microsoft 365 connector does not solve this
Cowork has no connector catalogue of its own. Anthropic documents that Cowork supports the same extensibility features as other Claude products, managed from Customize, and synced when a session starts. There is no standalone Outlook Calendar connector; calendar arrives inside Microsoft 365, alongside mail and files.
| Calendar | Owner | Native path in Cowork |
|---|---|---|
| Your work calendar | Your Microsoft 365 identity | Yes, read and write |
| Your secondary calendars | Same mailbox | Yes, read and write |
| A colleague’s calendar shared to you | Same tenant, different mailbox | Read only |
| A room or resource calendar | Same tenant | Read only |
| A personal Outlook.com calendar | Personal Microsoft account | No, cannot connect |
| A second employer or client tenant | Another tenant | Not at the same time |
Native Cowork versus Carly
| Need | Claude Cowork | Carly connector |
|---|---|---|
| Read several calendars in one work mailbox | Yes | Yes |
| Read a calendar shared to you | Yes | Yes |
| Book on your own work calendar | Yes, after admin consent | Yes |
| Book on a shared or delegated calendar | No | Yes |
| Connect a personal Outlook.com calendar | No | Yes |
| Hold two Microsoft identities at once | No | Yes |
| Act when an invite lands | No | Yes |
Inside one consenting tenant, on your own calendar, Cowork does the job well: it runs long multi-step tasks against real documents, and the read tools are accurate enough that availability questions come back right.
The gaps are structural rather than fixable, and the trigger is the sharpest. Cowork’s scheduled tasks run hourly, daily, weekly, on weekdays, or on demand, which is a clock rather than an event, and Anthropic documents the connector as on-demand rather than searching in the background. An invitation arriving starts nothing.
Carly holds several Microsoft identities at once, books on the one you name including calendars shared to you, and fires when the invite lands. Carly offers free Zapier-style workflows; AI agents start at $35/month.
Quick fixes when a calendar does not appear
| Problem | Fix |
|---|---|
| Cowork will not connect your Outlook.com address | That is a personal Microsoft account, which the connector rejects. Connect it to Carly instead |
| Every calendar tool comes back read-only | Write tools need one-time Entra Global Administrator consent for the tenant |
| Claude reads a colleague’s calendar but will not book on it | The published permission set omits Calendars.ReadWrite.Shared, so route the booking through Carly |
| A scheduled task spots a clash and leaves it | Event creates and updates cannot be pre-authorized natively, so each one waits for you |
| Connecting a client tenant dropped your own account | One Microsoft identity at a time on the native connector. Keep both in Carly |
Frequently asked questions
Can Claude Cowork connect two Outlook calendars?
It connects one Microsoft 365 identity and reads every calendar that identity can already see, including shared ones. Two separate Microsoft accounts is where it stops, because connecting the second replaces the first.
Can Claude Cowork add events to a shared Outlook calendar?
No. Anthropic’s published permission set includes Calendars.Read.Shared for reading and Calendars.ReadWrite for writing, but not Calendars.ReadWrite.Shared, which is the Microsoft Graph permission covering delegate and shared calendars.
Why can’t I connect my Outlook.com account to Claude?
The Microsoft 365 connector requires a Microsoft Entra tenant on a Microsoft Business plan. Anthropic states that personal Microsoft accounts, including @outlook.com, @hotmail.com, and @live.com, cannot be used to connect.
Can a scheduled Cowork task book meetings overnight?
Not on the native connector. Anthropic states that “Always allow” is not supported for creating or updating calendar events, so every write pauses for a human.
Does Claude Cowork react when a meeting invite arrives?
No. Cowork’s scheduled tasks run on a clock, hourly through weekly or manually, and the connector is documented as on-demand rather than searching in the background.
Related: What is Claude Cowork · Multiple Outlook calendars in Claude · Multiple Google Calendars in Claude Cowork · Best AI assistants for Outlook Calendar
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