nx_builder_authors_autograd.nx

nx_builder_authors_autograd.nx -- the BUILDER authors the L1 TRAINING-SUBSTRATE rung 1 (tape reverse-mode autograd on the team's own sovereign f32 tower). This is the shared keystone of the Nishi code LLM (S7) and the sovereign pixel engine -- the rung that moves TRAINING (not just inference) into the team's hands. Claude tutored the architecture (knowledge/specs/2026-06-09-tutoring-training-substrate-rung1.md); the Builder authors; the Engineer gates via nx_sov_build_run; gates: gradcheck vs mathematics, a model that provably learns, and BIT-EXACT reproducible training (the S-class-EXCEED axis from day one). license_tier: ORIGINAL