Gmail Labeling Script: "Contact Exists"

Google Apps Script that labels recent unlabeled Gmail threads:

• Contact Exists — sender email is in your Google Contacts and not in the Ignore contact group
• Not in Contacts — sender is unknown, or is in Ignore

Uses the People API (not the deprecated ContactsApp).

Files

File	Role
Code.gs	Script source
appsscript.json	Manifest (People advanced service + OAuth scopes)

Behavior

1. Searches newer_than:10d has:nouserlabels
2. Builds a contact email index once per run (paginated Connections + ContactGroups)
3. Labels each matching thread once

Install

1. Go to script.google.com → New project
2. Copy Code.gs from this repo into the editor (replace the default Code.gs)
3. Project Settings → show appsscript.json, then replace it with the repo’s appsscript.json
4. Confirm People API is enabled under Services / Advanced Google services (the manifest already declares it)
5. Run addLabelIfContactExists once and approve Gmail + Contacts when prompted
6. Triggers → add a time-driven trigger on addLabelIfContactExists (e.g. every 5–15 minutes)

Updating from an older copy

If you previously pasted the old README script that used ContactsApp, replace both Code.gs and appsscript.json with the current files on main, then run the function once to re-authorize.

Ignore group

Create a Google Contacts group named Ignore. Contacts in that group are labeled Not in Contacts.

Notes

• Labels are created automatically if missing.
• Only personal Google Contacts are checked (not the Workspace domain directory).
• Search window defaults to the last 10 days of unlabeled mail; change newer_than:10d in processEmails() if you want a different window.

License

MIT