Two documentation deliverables produced while T14 backtest runs:
1. Plan update (specs/2026-05-15-phase-e-4-a-temporal-foundation.md):
adds 'Execution Status' section reflecting actual T1-T14
progression. T5 deferred (real MBP-10 peek), T9 skipped (GRN
moved to E.4.B per integration notes), T10 partial (new C51
grad-input kernel landed but Mamba2 backward wiring deferred),
T14 in flight. Documents the 4 execution learnings:
research-first saved a week of duplicate kernel work; cheap
falsification experiments (Path 2, Path 3) avoided expensive
investments; C51 borrow was the largest single Sharpe-lift in
the session; GpuTensor/CudaSlice interop friction is the real
integration cost.
2. T10 patch sketch (specs/2026-05-15-t10-mamba2-backward-from-h-enriched.md):
ready-to-apply patch for ml-alpha::Mamba2Block adding a new
public method backward_from_h_enriched(cache, d_h_enriched).
Bypasses the W_out projection backward, accepts the
[B, hidden_dim] gradient from C51's grad-input kernel directly,
zero-initialises dw_out/db_out (AdamW step on zero grad is a
no-op with correct moment decay — effectively freezes W_out
params which is correct semantics since Phase E never uses
them). Includes the smoke binary wiring snippet that consumes
the new method via launch_alpha_c51_grad_input → Mamba2
backward → AdamW step. Application gated on T14 backtest
validation — if frozen Mamba2 already lifts Sharpe, T10
becomes optimisation rather than prerequisite.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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