Code-quality review caught: pearl_1_atom_kernel.cu computed
`clip_rate = atoms_clip_count[b] / (batch_size × 13)` using the
total-actions=13 sum across all branches. The headroom controller's
TARGET_CLIP_RATE=0.01 is calibrated against the per-branch clip event
rate. Using a denominator 3.25–4.3× larger than the per-branch
denominator made the controller systematically under-responsive — at
actual 1% per-branch clipping it would read ~0.23–0.31% and contract
headroom toward the 2.0 floor instead of holding the target.
Currently masked: `atoms_clip_count` is zero in Layer A (Layer B's
atoms_update_kernel migration is what populates it). Without this fix,
Layer B would inherit a silently-wrong formula that converges to the
floor rather than the target rate.
Fix: plumb `action_counts[4]` ({4, 3, 3, 3}) through the kernel
signature and use `batch_size × action_counts[b]` as the per-branch
denominator. Matches q_branch_stats_kernel's existing parameter pattern.
Test #2 launcher updated to allocate action_counts_buf and pass its
dev_ptr through the new kernel parameter slot. Audit doc entry added
per Invariant 7.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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