Spec: docs/superpowers/specs/2026-05-30-c51-atom-span-decouple-from-clamp.md
Diagnosed in cluster v5 (alpha-rl-rjsjq SHA 7064c9269) at step 371:
c51_v_max ratcheted up 1 → 24 → 53 → 859 → 1938 while WIN clamp swung
4910 → 568 → 7540 → 44 (volatile from MARGIN saturation). The slow
EWMA tracking win_bound time-averaged the early spikes, locking
atom span at extreme-value magnitude. Δz reached ~184 per atom — Q
could no longer discriminate +$500 from +$5000 wins.
Root cause: atom-span target was anchored on `MARGIN × pos_max_ema`,
where pos_max is the EXTREME-VALUE statistic across b=1024 batch
elements. The clamp bound (rightly fat-tail) and the atom span (should
be typical-magnitude) were treating two distinct concerns as one.
Fix F: anchor atom span on `atom_margin × mean_abs_pnl_ema` — true
central-tendency signal — while leaving the reward clamp on
pos_max_ema. The clamp can still admit fat-tail wins ($42k → +245)
and V regression (scalar head) retains the magnitude for PPO advantage,
but Q's CATEGORICAL distributional support now sizes itself for the
trades where most learning happens.
New ISV slot 685 (RL_C51_ATOM_MARGIN_INDEX, bootstrap 10.0).
RL_SLOTS_END 685 → 686.
Validation (local b=128 1k smoke):
metric | pre-Fix-F | with Fix F
v_max final | 1929 | 86.6 (22× tighter)
Δz per atom | 184 | 8.7 (resolution restored)
qpa final | +0.957 | +0.958 (Q-π alignment preserved)
mean_active | +$47k | +$34k (within smoke variance)
13/13 risk_stack_invariants + 20/20 trade_management_kernels +
integrated_trainer_smoke pass.
Tradeoff documented in spec: Q loses fat-tail categorical magnitude
(rewards beyond ±87 project to top/bottom atom), but V regression
preserves it. Acceptable for the lottery-ticket strategy where typical-
magnitude resolution matters more than fat-tail magnitude precision.
0fe825a8c5