Developer builds AI 'skeptic' agent that found four major flaws in his own design doc

A developer building a SaaS product created a custom AI sub-agent explicitly programmed to refute rather than approve documents, and barred it from offering any positive closing remarks. When he turned the agent on his own finished design document, it surfaced four major issues he had overlooked. The flaws included a self-contradicting rule about blocking outbound communication, a legally unconfirmed claim written in conclusive language, a completion condition referencing an undefined ledger, and a circular dependency between project phases. The developer noted that standard AI review prompts tend to produce overly validating responses, while inverting the success condition — making the agent's goal to disprove rather than approve — forced more rigorous scrutiny. He concluded that authors are poorly placed to review their own work, and that an adversarially framed AI reviewer can surface blind spots that conventional review misses.