Layer 1: Per-sample C51 loss clamp (MAX_CE=50) breaks PER feedback loop Layer 2: Label smoothing (ε=0.01) on Bellman target prevents log(0) Layer 3: IQN primary with fixed τ (QR-DQN style, CUDA Graph compatible) 5 tasks, each independently testable and committable. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>