convex.onDocumentUpdated watches one table and starts the automation when an existing document receives a new revision.
automations/changed-convex-message.automation.ts
table, optional component (default ""), optional OAuth deployment (default prod), and optional account. Trigger data includes the current document, documentId, revision, table, component, and action: "updated".
This trigger requires Convex Pro Data Sync and deployment:data:view. It reports the current document, not a field-level diff.