item 23 scored: both control axes confirm — pp30 29.3 (within ±5 of 31.6, 3x pauses bought nothing), x600 no recovery; d=1 ceiling is structural, ladder chapter closed

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

results-loop/PROTOCOL_UNIFIED.md

@@ -600,3 +600,33 @@ on the rungs.
     wider pause-chains); if BOTH land within +-5, the d=1 ceiling is
     confirmed structural and the ladder chapter closes as scored.
     Job: scripts/jobs/zzz_n_rungb_ctrl.sh.
+    AMENDMENT (2026-07-16 ~19:05, mid-run, Nils's call): arm A's eval
+    skipped to save ~50min GPU — the verdict was already decided by
+    training evidence (train loss memorized to 0.02-0.10 by step 200;
+    val easy 0.386->0.397->0.426, hard 0.357->0.376->0.421 across
+    e200/e400/e600 — monotone UP, textbook overfit, no recovery; k=0
+    sanity row reproduced base before the kill). Arm A scored from the
+    val trajectory: training time is NOT the binding constraint. Arm B
+    (pp30) runs in full as registered.
+
+--- Outcome, item 23 (scored 2026-07-16 ~23:55; rc=0). k=0 sanity rows
+reproduced base in both arms' evals (arm A's before its eval was
+skipped). Arm A (x600): scored from val trajectory per amendment — no
+recovery, mild overfit; training-time axis CONFIRMS the ceiling. Arm B
+(pp30): best cell 29.3 (2:36; 28.5 at 2:32) vs item-22 d=1's 31.6 —
+WITHIN the +-5 band, slightly below: 3x latent positions bought
+nothing (hard 33.9/36.2 vs 36.2; drop 14 vs 17; easy 51.7-55.2 vs
+62.1). Decision rule: BOTH axes confirm -> the d=1 break is
+STRUCTURAL. Neither longer training nor a longer pause-chain lets
+this carry absorb one scratchpad step; the binding constraint is the
+carried state itself (its per-position expressivity/fidelity, not its
+compute budget). Converging evidence from the same evening's
+microscopy (probe_discount*/probe_gsm*): the board natively carries
+plans ("Multiply", "subtract"), coarse magnitudes ("sixty/eighty"),
+and completion-state ("plus" kept alive at the 430 divergence — carry
+defers where FF commits a wrong digit at 99.3%), while exact digits
+appear only just-in-time, 1-2 positions pre-emission. The ladder
+chapter closes as scored in item 22; the loop program's live paths
+are state-side (rung-2 band-LoRA / wider merge, E2-N hardening,
+coarse-target auxiliary supervision matched to the medium) or the
+hybrid (A2), not longer/denser pause-chains.