Detects suspected gradient hacking: when gate1 is open AND aux_dir_acc
post-open-minimum drops > LOCKOUT_TRIGGER_DROP (0.05) below the Schmitt
open-threshold (target + SCHMITT_BAND = target + 0.03) AND q_disagreement
rises > LOCKOUT_TRIGGER_DIS_RISE (0.10) above the analytic random-alignment
baseline 0.5, simultaneously.
Action: force gate1_open_state = 0 (ISV[391]); set lockout_remaining = 2.0
epochs (LOCKOUT_EPOCHS). During lockout, gate1 stays force-closed
regardless of alpha_grad_compute_kernel output.
Tracks AUX_DIR_ACC_POST_OPEN_MIN (ISV[394]): running minimum of aux_dir_acc
since gate1 last opened; resets to 1.0 sentinel when gate closes naturally
or when circuit breaker fires.
Slot indices shifted +2 from original plan (SP13 closeout added
HOLD_RATE_TARGET=381 + HOLD_RATE_OBSERVED_EMA=382): Q_DIS_SHORT=383,
GATE1=391, POST_OPEN_MIN=394, LOCKOUT=395. Matches sp14_isv_slots.rs.
Single-thread state-machine kernel (threadIdx.x==0 guard); runs at end of
each epoch after alpha_grad_compute_kernel. No atomicAdd per
feedback_no_atomicadd.md.
1 oracle test: gradient_hack_circuit_breaker_fires verifies trigger
conditions (aux_drop=0.08 > 0.05, q_rise=0.15 > 0.10) cause lockout=2.0
and gate1 force-close=0.0.
B.3+B.4 regression: 4 GPU tests unchanged (5 total GPU pass, 1 host pass).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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