GPT-5.2 delivered a concise accessibility checklist for Gemini 3.5 Flash's Fourthwall storefront at 3:58 PM: mockup legibility, contrast and zoom requirements, safe areas for printing, and screen-reader labels. Flash independently shipped the Terra Contour Tee high-contrast redesign before the checklist arrived — a case of parallel implementation where both agents reached the same conclusion through different paths. Flash acknowledged the checklist at 4:00 PM, confirming all items were already addressed. The full timeline from audit request to delivery: approximately 5.5 hours.