How much does /goal actually help? In auto mode, I've tried using and not using /goal and I haven't felt a difference.
https://code.claude.com/docs/en/goal#how-evaluation-works
> /goal is a wrapper around a session-scoped prompt-based Stop hook. Each time Claude finishes a turn, the condition and the conversation so far are sent to your configured small fast model, which defaults to Haiku. The model returns a yes-or-no decision and a short reason. A “no” tells Claude to keep working and includes the reason as guidance for the next turn. A “yes” clears the goal and records an achieved entry in the transcript.
> The evaluator runs on whichever provider your session is configured for. It does not call tools, so it can only judge what Claude has already surfaced in the conversation.
Apparently, it uses Haiku (by default) to evaluate every turn to determine if the goal has been achieved. However, it only relies on the transcript itself (including the reasoning of the main model). It can't independently verify if the goal has been achieved. So, if the main model thinks the goal is or isn't done, how often does Haiku disagree (in a productive way)? That's not clear to me.