docs(sp13): v2 spec + plan after critical review
Spec v2 supersedes v1 with five major fixes from the critical review:
- Drop alpha-vs-benchmark reward (mathematically tautological — Long trades had
alpha = -costs always against always-long benchmark)
- Split Phase 0 into 0a (Hold-only, clean test of user hypothesis) + 0b (aux
amplification probe, only if 0a partial), avoiding the v1 confounded experiment
- Bound direction-skill bonus relative to |alpha| (cap_ratio × |alpha|) to prevent
reward gaming on small-alpha correct-direction losers; spec adds 8-quadrant
worked-example matrix verifying the no-negative-EV invariant
- Replace 5-epoch absolute-threshold gate with 10-epoch trajectory criterion to
avoid false-negatives from aux head underconvergence
- Aux_w controller adds dual-EMA stagnation detector (decays toward base when
no improvement) — prevents permanent destabilization of Q-head in
data-limited case
Plan v2 mirrors spec changes:
- Phase 0a (Hold elimination + dir_acc instrumentation, ~300 LOC, 1 atomic commit)
- Phase 0b (aux_w controller replacement, conditional, ~80 LOC)
- Layer B (aux head regression -> binary classification, ~120 LOC)
- Layer C (skill bonus + luck discount with calibrated bounds, ~150 LOC)
- Layer D (30-epoch validation + 3 new pearls)
ISV slot allocation [372..380): drops slot 371 (BENCHMARK_PNL_CUMULATIVE),
adds 374 (AUX_DIR_ACC_LONG_EMA — stagnation), 379 (SKILL_BONUS_CAP_RATIO).
Plan integrates Explore-agent touch-list (50-70 sites) with corrected enum
ordering: Short=0, Long=1, Flat=2 (preserves codebase Short-first convention,
avoids 30+ stale-comment churn). Adds direction-bias signal handling at
experience_kernels.cu:5159 (Hold's 0.5 softening gate vanishes -> [1, 1, 0]).
Three new pearls planned for Layer D close-out:
- pearl_redefine_success_for_predictive_skill
- pearl_skill_bonus_must_be_alpha_bounded (calibration lesson)
- pearl_reward_quadrant_audit_required (meta-pearl)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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