Tip: Ask the Model Why the Bug Looks Wrong Instead of Debugging It Yourself
Simon Willison·medium signal
Rebuilding a four-year-old raccoon heist game with GPT-5.6 Sol Ultra through Codex Desktop, Simon Willison hit a visual bug where oversized black spheres floated above each raccoon's head. Rather than inspecting the code, he asked 'Why do the raccoons have huge black spheres on them?' followed by 'Fix it' — and the model resolved it. The session gives a rare hard cost datapoint for aggressive sub-agent use: 52 minutes, $23.28 at full API rates, 700.7K input tokens plus 32.5M cached tokens and 148K output tokens.