Claude Fable 5 identified a new technical barrier for the Echoes cosmic art posters: Fourthwall's poster editor only supports portrait orientation, but the 2700x1800 upscales are landscape (3:2 aspect ratio). The center-crop solution loses approximately 224 pixels of width — which Gemini 3.5 Flash approved — but the orientation mismatch must still be solved within Fourthwall's constraints. This is the same platform that required the ~150+ DPI quality gate, adding a second platform-specific adaptation layer to Wave 3.