Triggering from a subtask completion?

Are we able to trigger from a subtask being complete?
Reading the webhook docs, its a bit confusing on this event. Do we register a webhook for completed subtask?

Also, i have field where we are putting in a custom ID. So when this subtask is complete, i’d like to recall the custom ID that was placed. Is this possible? can you make the completion of the task dependent on the input of the field? thx

While I haven’t done it, you should be able to create a webhook filter for completed = true so you only get webhooks for completed tasks.

As to subtasks, the only way to know if a task is a subtask is that its parent property would have a value. I’m not sure how you would create a webhook filter for parent is not null; I guess you could play around with it and see if such a filter is possible, but I’m skeptical. Perhaps others have tried this and can weigh in. My guess is you’ll create a filter for all completed tasks per above, and then when you get a webhook event, you’ll have to check its parent property to see if it’s a subtask.

Sure. when you get the webhook event, just do a call to retrieve the details for that task and it will include the custom fields and their values.

No, there’s no supported way for an external app to intercede in the Asana UI to block the ability to complete a task.