How to Monitor Your Inbox with Delta Sync

Delta sync lets you track inbox changes incrementally — instead of re-fetching all emails, you get only what’s new, modified, or deleted since your last check.

How Delta Sync Works

1. Initial sync — call search-emails with deltaMode: true (no token). Returns current emails plus a deltaToken.
2. Store the token — save the deltaToken from the response.
3. Incremental sync — call again with the same deltaMode: true and your stored deltaToken. Returns only changes since that token was issued.

Each incremental call returns a new deltaToken for the next round.

Initial Sync

“Get my current inbox state for monitoring”

tool: search-emails
params:
  deltaMode: true

The response includes:

• Current inbox emails (up to the configured count)
• A deltaToken string to use on subsequent calls

Save this token — you’ll need it for all future incremental checks.

Incremental Sync

“Check for new emails since my last sync”

tool: search-emails
params:
  deltaMode: true
  deltaToken: "your-saved-token-here"

The response includes:

• New emails received since the token was issued
• Modified emails (e.g. marked as read, flagged, moved)
• Deleted email IDs (via @removed entries)
• A new deltaToken for the next call

Handling Token Expiry

Delta tokens expire after an extended period of inactivity. If you receive a 410 Gone error, your token has expired — start a fresh initial sync (no token) to get a new baseline.

// Recovery pattern:
1. Call with deltaToken → 410 error
2. Discard expired token
3. Call without deltaToken (fresh initial sync)
4. Save new deltaToken

Use Cases

Inbox Monitoring Agent

Poll for new emails on a schedule and process them automatically:

1. Initial sync → store token
2. Every N minutes: incremental sync with stored token
3. For each new email: read content, categorise, flag, or forward
4. Store new token for next iteration

Audit Trail Logging

Track all inbox changes for compliance:

1. Initial sync to establish baseline
2. Incremental syncs to log every new, modified, and deleted email
3. Write changes to an audit log with timestamps

Notification Triggers

Detect emails from specific senders or matching patterns:

1. Incremental sync to get new emails
2. Filter by sender, subject, or other criteria
3. Trigger alerts, create tasks, or escalate as needed

Tips

• Delta sync works per-folder (defaults to inbox). Specify folder to monitor other folders.
• Store tokens persistently between agent sessions — they remain valid for extended periods.
• Use outputVerbosity: "minimal" for efficient polling when you only need to detect changes, not read full content.
• Combine with read-email to get full content of specific changed messages after detecting them.
• Use count to control how many results are returned per sync call.

Related

• Find Emails — search and filter emails
• Using Outlook Assistant in Agents — agent workflow patterns
• Tools Reference — search-emails