This is fantastic. There are a ton of use cases where you'd want to be able to build an integration that hooks back to your running agent session. OpenClaw has this today, but it's pretty janky. Hopefully this is coming to Claude Cowork as well.

My use case is that I have a separate system that provides human approvals for what my agent can do. Right now, I've had to resort to long-polling to give a halfway decent user experience. But webhooks are clearly the right solution. Curious to see how it ends up being exposed outside of these initial integrations.