STATE AND CONTROL FLOW

CHAPTER SUMMARY State is the information that survives from step to step, and the harness keeps it in a state container that should be explicit, serializable, versioned, and minimal. Checkpoints are consistent snapshots that limit how much work is lost after a failure. Pause and resume let the harness hold a run steady, especially for human-in-the-loop approvals, and need timeout rules and rechecks after resuming. Rollback returns files and state to a known-good point, but cannot unsend outside actions, which must be prevented, approved, or compensated. KEY TERMS REVIEW State: information that survives from one step to the next. State container: where and how state is stored. Durable storage: storage that survives restarts. Serializable: able to be converted to text or bytes and back. Checkpoint: a saved snapshot to return to. Pause and resume: stopping and later continuing exactly where left off. Human-in-the-loop: a person placed at chosen points to approve or review. Rollback: undoing steps to a known-good point. Compensating action: a new action that cancels an earlier action's effect.