Inventory penalty makes flat optimal — model learns to do nothing.
Instead: penalize inaction proportional to model's own predicted edge
(Q-value spread). Creates virtuous cycle: better temporal attention →
higher self-imposed penalty for missed trades → more trading on signal.
No hindsight bias (uses predicted edge, not actual price change).
Micro-reward (already exists) rewards correct positioning.
Churn penalty (new) prevents rapid flips.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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