Following the customized notification template docs(https://developer.harness.io/docs/platform/templates/customized-notification-template/), we can customize Slack notifications effectively — except for the ability to @mention the individual responsible for a commit directly in Slack. We can retrieve the commit author's email using expressions like or , but there is no way to resolve that email to a Slack user ID for tagging.

A built-in Harness expression/function (e.g., <+slack.lookupByEmail(<+trigger.committerEmail>)>) that resolves an email address to the corresponding Slack user ID, enabling proper <@SlackUserId> mentions in Slack notification templates would be really helpful here. We want to avoid going the route of doing all of it in a custom bash template.