Access another user's Outlook/Microsoft 365 email and calendar as a delegate via Microsoft Graph API.
This skill is designed for scenarios where:
assistant@domain.com)| Feature | Direct Access (/me) | Delegate Access (/users/{id}) |
|---|---|---|
| --------- | ---------------------- | -------------------------------- |
| API Base | /me/messages | /users/{owner}/messages |
| Send Email | Appears "From: Owner" | Appears "From: Assistant on behalf of Owner" |
| Calendar | Full control | Based on permission level granted |
| Permissions | Mail.ReadWrite, Mail.Send | Mail.ReadWrite.Shared, Mail.Send.Shared, Calendars.ReadWrite.Shared |
~/.outlook-mcp/config.json{
"client_id": "your-app-client-id",
"client_secret": "your-app-client-secret",
"owner_email": "owner@domain.com",
"delegate_email": "assistant@domain.com"
}
The owner_email is the mailbox the assistant will access as a delegate.
The app registration needs delegated permissions (not application permissions):
Mail.ReadWrite.Shared - Read/write access to shared mailboxesMail.Send.Shared - Send mail on behalf of othersCalendars.ReadWrite.Shared - Read/write shared calendarsUser.Read - Read assistant's own profileoffline_access - Refresh tokensThe owner must grant the assistant delegate access via Exchange/Outlook:
PowerShell (Admin):
# Grant mailbox access
Add-MailboxPermission -Identity "owner@domain.com" -User "assistant@domain.com" -AccessRights FullAccess
# Grant Send-on-Behalf
Set-Mailbox -Identity "owner@domain.com" -GrantSendOnBehalfTo "assistant@domain.com"
# Grant calendar access (Editor = can create/modify events)
Add-MailboxFolderPermission -Identity "owner@domain.com:\Calendar" -User "assistant@domain.com" -AccessRights Editor -SharingPermissionFlags Delegate
Or via Outlook Settings:
The owner can add the assistant as a delegate in Outlook → File → Account Settings → Delegate Access.
The assistant authenticates as itself via OAuth2, then accesses the owner's resources using the /users/{owner@domain.com}/ endpoint.
./scripts/outlook-token.sh refresh # Refresh expired token
./scripts/outlook-token.sh test # Test connection to BOTH accounts
./scripts/outlook-token.sh get # Print access token
./scripts/outlook-mail.sh inbox [count] # Owner's inbox
./scripts/outlook-mail.sh unread [count] # Owner's unread
./scripts/outlook-mail.sh search "query" [count] # Search owner's mail
./scripts/outlook-mail.sh from <email> [count] # Owner's mail from sender
./scripts/outlook-mail.sh read <id> # Read email content
./scripts/outlook-mail.sh mark-read <id> # Mark as read
./scripts/outlook-mail.sh mark-unread <id> # Mark as unread
./scripts/outlook-mail.sh flag <id> # Flag as important
./scripts/outlook-mail.sh delete <id> # Move to trash
./scripts/outlook-mail.sh archive <id> # Move to archive
./scripts/outlook-mail.sh move <id> <folder> # Move to folder
./scripts/outlook-mail.sh send <to> <subj> <body> # Send on behalf of owner
./scripts/outlook-mail.sh reply <id> "body" # Reply on behalf of owner
Note: Emails will show "Assistant on behalf of Owner" in the From field.
./scripts/outlook-calendar.sh events [count] # Owner's upcoming events
./scripts/outlook-calendar.sh today # Owner's today
./scripts/outlook-calendar.sh week # Owner's week
./scripts/outlook-calendar.sh read <id> # Event details
./scripts/outlook-calendar.sh free <start> <end> # Owner's availability
./scripts/outlook-calendar.sh create <subj> <start> <end> [location]
./scripts/outlook-calendar.sh quick <subject> [time]
The key change is replacing /me with /users/{owner_email}:
# Direct access (old)
API="https://graph.microsoft.com/v1.0/me"
# Delegate access (new)
OWNER=$(jq -r '.owner_email' "$CONFIG_FILE")
API="https://graph.microsoft.com/v1.0/users/$OWNER"
When sending mail as a delegate, you must specify the from address:
{
"message": {
"subject": "Meeting follow-up",
"from": {
"emailAddress": {
"address": "owner@domain.com"
}
},
"toRecipients": [{"emailAddress": {"address": "recipient@example.com"}}],
"body": {"contentType": "Text", "content": "..."}
}
}
The recipient sees: "Assistant on behalf of Owner
| Action | Required Permission | Exchange Setting |
|---|---|---|
| -------- | ------------------- | ----------------- |
| Read owner's mail | Mail.ReadWrite.Shared | FullAccess or Reviewer |
| Modify owner's mail | Mail.ReadWrite.Shared | FullAccess or Editor |
| Send as owner | Mail.Send.Shared | SendOnBehalf |
| Read owner's calendar | Calendars.ReadWrite.Shared | Reviewer+ |
| Create events on owner's calendar | Calendars.ReadWrite.Shared | Editor |
"Access denied" or "403 Forbidden"
→ Check that the assistant has MailboxPermission on the owner's mailbox
"The mailbox is not found"
→ Verify owner_email in config.json is correct
"Insufficient privileges"
→ App registration missing .Shared permissions (check Azure AD)
Emails send but don't show "on behalf of"
→ Missing SendOnBehalf permission. Run:
Set-Mailbox -Identity "owner@domain.com" -GrantSendOnBehalfTo "assistant@domain.com"
"Token expired"
→ Run outlook-token.sh refresh
~/.outlook-mcp/ - protect this directory~/.outlook-mcp/config.json - Client ID, secret, and owner/delegate emails~/.outlook-mcp/credentials.json - OAuth tokens (access + refresh)/users/{owner} instead of /meowner_email and delegate_email config fieldsfrom field.Shared variants共 1 个版本