{
  "rationale": "From head_ablation.py sweep on 1000 COCO val images: 10 heads produced the largest individual F1 drops when ablated. Cumulative pruning of those 10 yields peak F1=0.9159 (vs baseline 0.8939); K=20 cumulative still ahead at F1=0.8971; K=30+ cliff-drops below 0.35. Peak pruning point is K=10.",
  "peak_K": 10,
  "baseline_F1": 0.8939,
  "pruned_K10_F1": 0.9159,
  "pruned_K20_F1": 0.8971,
  "heads_pruned_K10": "top 10 of ranked_most_prunable_first from head_importance.json",
  "how_to_apply": "At load time, for each (block, head) in the pruned list, zero block.attn.proj.weight[:, head*64:(head+1)*64]. See apply_mask.py."
}