P0a smoke (train-67gqb on f934ea171) returned PARTIAL: aux_dir_acc climbed
0.149 → 0.483 in 10 epochs (signal exists), but val_win_rate stuck at 0.4638
and observed_hold_rate climbed to 0.479 despite controller saturating at
2.4× base. Two findings drive P0b:
(1) aux_w=0.05 (SP11-era clamp) starves the aux head of gradient. Replace
inverted formula at training_loop.rs SP11 site with deficit+stagnation:
deficit = max(0, target - short_ema)
improve = max(0, short_ema - long_ema)
stag = (deficit > 0.005) ? clamp(1 - improve/deficit, 0, 1) : 0
aux_w = base × (1 + 5 × deficit) × (1 - 0.7 × stag),
clamped [0.3×base, 3.0×base]
base 0.05 → 0.5 (10× lift). Stagnation decay prevents permanent
destabilisation in data-limited case. Formula extracted as host helper
`compute_aux_w_p0b(target, short, long)` for unit-test coverage.
(2) HOLD_COST_BASE=0.001 was too weak — max cost 0.005/bar × 30-bar hold =
0.15 cumulative vs ±5-10 reward range = <3% of magnitude. Lift to 0.005
(max 0.025/bar × 30 bars = 0.75 cumulative ≈ 10-15% of capped reward).
Genuinely deters lazy Hold without crippling MFT use. Constructor
static-init unchanged: it still writes the (now-lifted) HOLD_COST_BASE
constant to slot 380 at fold boundary.
Per pearl_event_driven_reward_density_alignment tension already addressed
in P0a spec; the lift doesn't change the architecture, just the calibration.
Per feedback_isv_for_adaptive_bounds: base/gain/decay/floor/ceil are
numerical anchors; target/short/long EMAs read from ISV.
Tests: 3 new unit tests for controller formula (aux_w_at_target_returns_base,
aux_w_stagnation_decays_to_floor, aux_w_improving_amplifies_above_base).
14 SP13 GPU oracle tests + 14 SP12 reward-math tests still green; no kernel
changes.
Audit-doc updated with P0b section per Invariant 7.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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