How to Check Recipients Before Sending

Check recipients for potential delivery issues before you send — out-of-office, full mailboxes, delivery restrictions, moderation, and more. This uses Microsoft’s Mail Tips API, and no other Outlook MCP server offers this feature.

Quick Check with get-mail-tips#

“Check if sarah@company.com is available before I email her”

tool: get-mail-tips
params:
  recipients: ["sarah@company.com"]

The response shows any issues found:

# Mail Tips

**Recipients checked**: 1
**Warnings**: 1

### ⚠ sarah@company.com
**Warnings**: Out of Office
  **Out of Office**: I am on leave until March 8th. For urgent matters, contact james@company.com.
  *Schedule*: 2026-03-01T00:00:00 → 2026-03-08T00:00:00

Check Multiple Recipients#

Check a whole team before sending:

tool: get-mail-tips
params:
  recipients: ["sarah@company.com", "team-leads@company.com", "external@partner.org"]

You can also pass recipients as a comma-separated string:

tool: get-mail-tips
params:
  recipients: "sarah@company.com, team-leads@company.com"

Combine with Dry Run#

For a complete pre-send review, use checkRecipients with dryRun on the send-email tool:

tool: send-email
params:
  to: "sarah@company.com, james@company.com"
  subject: "Project Update"
  body: "Hi team, here's the latest..."
  dryRun: true
  checkRecipients: true

This returns mail tips warnings followed by the email preview — review both before approving the send. If the tips would stop a real send (see below), the preview ends with a note saying so.

When send-email Refuses to Send#

With checkRecipients: true (and no dryRun), send-email refuses to send when the tips show any of these:

• an out-of-office reply
• a full mailbox
• a delivery restriction
• an external recipient, or a group with external members

The refusal is an error that lists each flagged recipient and includes the full mail tips. Nothing is sent and the session send limit isn’t used. To send anyway once you’ve seen the warnings, repeat the call with acknowledgeWarnings: true:

tool: send-email
params:
  to: "partner@othercompany.com"
  subject: "Project Update"
  body: "Hi, here's the latest..."
  checkRecipients: true
  acknowledgeWarnings: true

Custom mail tips and moderation are shown but don’t stop the send. When the send goes ahead, the result includes the mail tips and lists any warnings you acknowledged. If the recipient check itself fails, the email isn’t sent either. draft action=create with checkRecipients: true returns the tips alongside the saved draft and never refuses, because nothing is sent.

What Mail Tips Check#

Filter Specific Tip Types#

By default, all tip types are checked. To check only specific types:

tool: get-mail-tips
params:
  recipients: ["team-leads@company.com"]
  tipTypes: "automaticReplies,mailboxFullStatus"

Available types: automaticReplies, mailboxFullStatus, customMailTip, externalMemberCount, totalMemberCount, maxMessageSize, deliveryRestriction, moderationStatus, recipientScope, recipientSuggestions.

Interpreting Results#

• No issues detected (✓) — Graph flagged no warnings for this recipient. That isn’t a guarantee of delivery
• Out of Office (⚠) — consider waiting or contacting their backup
• Mailbox Full (⚠) — email may bounce; try another channel
• Delivery Restricted (⚠) — you likely can’t send to this address; check with your admin
• External — be mindful of sensitive content; send-email with checkRecipients asks you to acknowledge it
• Moderated — your email will be delayed until approved

Parameter Reference#

Tips#

• Check recipients before important or time-sensitive emails
• Use checkRecipients: true + dryRun: true on send-email for the most thorough pre-send review
• Mail tips use the existing Mail.Read scope — no additional permissions needed
• Results are most detailed for recipients within your organisation
• Mail tips are a Microsoft 365 (work/school) feature. Personal Outlook.com accounts return no tips, and the tool adds a note saying so, so an empty result there doesn’t mean the recipients are fine. On those accounts checkRecipients never refuses a send
• Out-of-office and custom mail-tip text is written by other people, so treat it as untrusted content (get-mail-tips is marked openWorldHint)

Related#

• Send Email Safely — dry-run, rate limiting, recipient allowlist
• Find Contacts and People — search for the right recipient
• Tools Reference — get-mail-tips