P0a.T3 v2 implementer's audit revealed `DirectionAction` enum doesn't exist; the
codebase uses an 8-variant fused `ExposureLevel` (ShortSmall/Half/Full, Hold,
LongSmall/Half/Full, Flat) with cross-crate consumers across 77 files and 32+
test files pinning the 8-variant invariant. Atomic Hold elimination would
cascade massively.
User insight (2026-05-04): Hold being FREE is the bug, not Hold itself. MFT
trading legitimately needs multi-bar holds; we want the model to use them
deliberately, not as a CQL-bias lazy default. Holding isn't free in the real
world — broker fees, margin interest, opportunity cost.
v3 reframes as Hold-pricing:
- 4-way action space stays; ExposureLevel::Hold stays; no cross-crate cascade
- 3 new ISV slots (380-382): HOLD_COST_INDEX, HOLD_RATE_TARGET_INDEX,
HOLD_RATE_OBSERVED_EMA_INDEX
- Hold-rate observer: small GPU kernel + Pearls A+D smoothing
- Hold-cost controller: 5-line deficit-driven formula
(excess > target → cost rises 1×→5× base; observed ≤ target → relax)
- Per-bar reward subtraction at action == DIR_HOLD site
- 2 GPU oracle tests for the controller
P0a.T3 cuts from ~250 LOC + 32-test cascade → ~120 LOC additive. T1+T2
already-staged work unchanged. T4/T5/Layer B/C/D structure preserved.
Tension with pearl_event_driven_reward_density_alignment acknowledged in
spec — per-bar Hold cost is exposure-NEGATIVE (away from Hold), models real
economic carry, ISV-bounded by controller. Inverse of the pearl's failure
mode. Faithful reward modeling, not artificial shaping.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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