Prove-It: An Adversarial Verification Agent Skill for Claude Code (2026 Guide)
An adversarial verification agent is a checker with an inverted objective: instead of collecting signals that confirm a claim, it is built to refute it. Prove-It turns that refuter on a coding agent’s own “done” claim, answering with one of four verdicts — PROVEN, FAILED, NOT PROVEN, or BLOCKED — instead of a paragraph of reassurance. That is the short answer. The rest of this guide explains why the pattern exists, what the four verdicts actually mean, where the skill stops being useful, and how a 12-case self-authored benchmark should be read without overselling it. ...