- train_specialist_pt.py: pure PyTorch trainer replacing Fabricate binary.
No SQLite/WAL — saves checkpoint.pt + history.json only. Fabricate was
causing D-state IO blocking on the HDD due to continuous WAL writes.
- eval_specialist_pt.py: PyTorch eval with confusion matrix, threshold
analysis, guardrail assessment, and deployment verdict.
- capacity_sweep.py: updated to call PyTorch scripts; TIERS now include
heads field (4/6/8) since PyTorch supports multi-head unlike Fabricate.
- prereq_op_binary_split.py: evaluate_combined rewritten in PyTorch.
- Performance fix in train_specialist_pt.py: load training data onto GPU
once and sample via torch.randint instead of DataLoader (eliminates
Python/CPU overhead on tiny datasets). Fix applied, not yet timed.
Next session: time the fix, then run sweep_all_gates.sh --pilot-only.
See HANDOFF-2026-03-31.md for full context.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>