/goal might be the most powerful feature in Claude Code that you're not using. And the part everyone gets wrong has nothing to do with the feature. Here's the mechanism. You hand Claude a completion condition. It works turn after turn. After every turn, a separate evaluator model (Haiku by default) checks the output against your condition. Condition unmet? Claude keeps going. Met? It logs the proof and hands control back. The design choice that matters: the agent doing the work never decides…