bench.py attributes generation time to encode / per-step / decode stages via the pipeline's own step_callback; parity.py snapshots decoded float32 pixels for a fixed prompt/seed/size (+LoRA) matrix and asserts later runs stay uint8-identical — the quality gate for every optimization commit. Reference outputs and results land in tools/reference/ (gitignored). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>