Agents you stopped are less likely to come back on their own

A subagent is a helper agent Claude starts to work on part of a task. When you stop an observer agent, a subagent that watches another, Claude Code saves a marker that it was stopped. Saving that marker is now retried if it fails, and the marker is checked first, so trying to bring the agent back is blocked.

When Claude tries to resume a stopped agent and the agent's saved state cannot be found, Claude Code now treats it as stopped by you. It reports that the agent was stopped by the user and won't be resumed.