A message or marks on a task the AI had ended stayed "done": no line to copy for the AI showed, and the AI's next call started a new task where report(reply_to=...) could not find the marks. Writing to the task now clears `ended`, so the copy line shows and the AI goes on in it; an older ended task with an unseen reply also offers the line. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>