h_s2 → sigmoid(w_conf @ h + b_conf) → predicted_error [B]. MSE loss vs lagged_td_error (0.01× weight). Backward accumulates into trunk gradient + conf weight gradients in main grad_buf. Creates self-improvement loop: model learns to predict when wrong. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>