Pre-registration: clean-list subgoal-draws selection (#6 rung (b′))

2026-08-08 ~17:5xZ. Immutable once posted. Idea #6, the escalation named by the rung-(b) stage-1 close, whose closing clause requires this post. The rung-(b) pre-reg is inherited verbatim except where this post explicitly amends it — one design change, one re-scoped stage-1 bar, fresh naming and cost clauses. Zero training. The instrument delta is small and lands oracle-gated before launch; any forced semantic deviation gets an amendment posted before launch (the rung-(a) precedent).

Question

Rung (b) closed at table cost: its stage-1 bar (a) — every sampled candidate clean on ≥ 90% of rows — failed at 20/60, because 11.5% of T=1.0 sampled draws derail into budget-truncated multilingual gibberish (55/480; greedy clean 60/60; 0.885⁸ binomial arithmetic reproduces the row rate). Everything else passed: diversity is real (97% of rows ≥ 2 unique strings), clean candidates are subgoal-shaped with genuine adjacent-phase alternatives, and the frozen scorer already refuses the gibberish (self-certainty picks a truncated candidate on 0/60 rows, median rank 9/9). Δ_bon and Δ_ceil — the rung’s actual payload — were never measured.

Rung (b′) asks the same question with the failure mode structurally removed: exclude budget-truncated candidates from every scorer’s candidate list, re-adjudicate the stage-1 bars on the filtered list, and — if they pass — run the two conditioned arms exactly as rung (b) froze them.

The one design change (frozen): the eligible-candidate list

Pass 1 is unchanged: per frame, 9 candidates — greedy (candidate 0) plus 8 sampled at T=1.0, draws10_t1 seeding verbatim, decoded and dumped exactly as rung (b) specified (candidates are still recorded as decoded, unfiltered, with their truncated flags — the flag is already a first-class field on every dumped candidate).

Selection-side, every scorer — the primary self-certainty pick, the token-F1 ceiling pick, and the record-only alternates (mean logprob, medoid) — operates on the eligible list:

eligible = all candidates with truncated == false; if that list is empty, eligible = [candidate 0] (greedy as decoded — the fallback row is recorded and counted).

Ties still break toward the lowest original index (greedy first); picks are recorded as original-list indices. Nothing else about selection changes: no re-phrasing, no dedup changes, no new scorer.

Rejected alternative, reasons banked now: moving the sampler to nucleus/lower-T was the other named fix. Rejected because (i) it changes the sampling distribution, so every banked stage-1 number (11.5% derailment, 97% diversity, 65% pick≠greedy) stops transferring and stage 1 must be re-bought on GPU; (ii) the #19 dT table says sampled behavior is monotone in T — lower T trades away exactly the diversity that gives width its value; (iii) the exclusion filter preserves pass-1 byte-identity with the banked stage-1 table, which makes stage 1 free (below). Nucleus/lower-T remains available only to a future pre-reg.

Written priors (computed from the banked stage-1 table, this session, before this post froze)

The stage-1 pass-1 decode is deterministic given checkpoint, plan, frames, seeds and temperature — all unchanged — so the banked 60-row table (reports/analysis__subgoal_draws_stage1_table.json) IS rung (b′)’s stage-1 data. Re-scoring it through the frozen filter and the committed scorer functions (bijou.eval.subgoal_scoring):

• The filter is structural, not behavioral, on every observed pick: exclusion changes the self-certainty pick on 0/60 rows and the token-F1 ceiling pick on 0/60 rows (both scorers land on truncated candidates 0/60 times unfiltered). 40/60 rows carry ≥ 1 truncated candidate, so the filter binds on the list two rows in three while changing no observed pick — exactly the “structural version of what SC already does” the close post projected.
• Filtered bars: ≥ 1 eligible sampled candidate on 60/60 rows (no row lost all 8 draws; binomial expectation of an all-8-truncated row at 11.5% is ~3×10⁻⁸); ≥ 2 unique eligible strings on 57/60 rows (95%); top pooled eligible sampled string 23/425 (5.4%).
• Carried from the close post: SC pick ≠ greedy on 39/60 rows (65%); every inspected clean candidate subgoal-shaped and phase-relevant.

Stage 1 (CPU, zero GPU): mechanical re-adjudication on the banked table

The execution lands a small re-adjudication script that recomputes the numbers above from the banked table json through the committed filter + scorer code, and gates stage 2 on the re-scoped bars:

Bar (a)’s original “non-truncated” clause is discharged by construction on the filtered list; its surviving content is non-emptiness, which is what (a′) scores. Fail on any bar → stage 2 does not run and the table is the rung-(b′) result (inherited rule). Since the priors are computed from banked data, a failed bar here would mean instrument breakage, not new evidence — the script aborts loudly rather than adjudicating in that case.

Stage 2 — inherited verbatim

Everything from the rung-(b) pre-reg’s stage-2 section applies unchanged except the candidate list and the names: same two conditioned arms (bon = self-certainty pick over the eligible list, deployment-honest primary; ceil = token-F1-vs-true-label pick over the eligible list, record-only bound), same plan (plans/holdout_curated_v0_k4l2.json), same checkpoint (bijou_arb_rcond_100k_ddp4/step_100000), seed 0, full k4l2 panel, same order and batch size as the banked baseline; label-less frames render no subgoal in ceil and the SC pick in bon; both arms decode actions on the deployment fast path with pass 2’s generate list excluding subgoal.

Naming (fresh): policy names and stems must be distinct from rung (b)’s — they carry the filter (spelling is implementation’s, e.g. _boncleansubgoal / _ceilcleansubgoal), and the report records the candidate-filter rule alongside the scorer id. The ceil arm’s oracle-informed text must never appear in a deployment-named row (inherited oracle v).

Frozen reads — inherited verbatim

Reads 1–6 of the rung-(b) pre-reg apply word-for-word with “the 9 candidates” read as “the eligible list”: primary Δ_bon = chunk_mae(bon) − 5.8026 with the paired per-frame (bon − self) read vs the banked rung-(a) self npz quoted beside it; Δ_ceil on the labeled subset with the same interpretive frame (Δ_ceil ≈ Δ_self ⇒ the family closes at this width regardless of scorer; Δ_ceil clearly below both ⇒ the Δ_ceil-to-Δ_bon gap prices the scorer and the Δ_ceil-to-−0.290 gap prices wider generation); scorer-agreement records (now also: per-row eligible-list size distribution and fallback-row count); horizon decomposition; first_mae mirrors; execution oracles (state-copy byte-match, anchor re-pool exact, modes + scorer + filter ids in every name and report). Seeded bootstrap CI95 (seed 0, 10,000), decode-noise floor (−0.0008, ±0.016) quoted beside any small delta.

Numbered expectations (banked before data)

1. Stage-1 bars (a′)–(d) pass on the banked table via the committed script — confidence high (they are computed above; failure = instrument breakage).
2. Δ_ceil < Δ_self with CI clear of zero on the paired (ceil − self) read — the width contains better-phase texts — confidence medium (inherited; stage-1 eyes saw real adjacent-phase alternatives).
3. Δ_bon lands between Δ_self and Δ_ceil, closer to Δ_self (inherited, confidence medium-low — whether distributional confidence discriminates phase from a single frame is still the rung’s open number; stage 1 says SC discriminates gibberish, which is not phase).
4. Gains, where present, concentrate late-horizon; first_mae moves little — confidence medium (inherited).
5. The SC pick differs from the greedy string on ≥ 40% of frames — confidence medium (upgraded from rung (b)’s ≥ 20% low: the stage-1 measurement was 65%, and the filter changed no pick).
6. Falsified if the paired (bon − self) CI95 does not lie entirely below zero (inherited verbatim). The Δ_ceil read then adjudicates no-diversity vs no-scorer, and that adjudication routes the escalation exactly as rung (b) froze it: scorer-side (masked-contrast MG-Select form / TOPReward history-conditioning, pre-mapped on the escalation queue item) vs planner-side (HiRoC-direction SFT) vs close-the-family. Any escalation needs its own pre-reg citing this result. No prompt fishing, no post-hoc scorer promotion, no candidate re-phrasing, no filter-rule tuning.

Cost & scheduling

Stage 1 is CPU-only (banked data). Stage 2: full-panel pass 1 (9 candidates off one shared prefill) + two conditioned greedy panel decodes (banked rate 0.081 s/frame ≈ 35–50 min each) — projected ~2.5–3.5 GPU-h. Pre-registered ceiling ≤ 5 GPU-h (tighter than rung (b)’s 6: its stage-1 spend is already banked); if a first-200-frame rate measurement projects past it, all arms drop to the frozen q4 subset (4,301 rows, the #19 clause verbatim) and the switch is recorded. Venue: local GPU, first quiet window after the noise-ladder rung-2 obligations (stage-2 confirm + seating — that pre-reg’s launches come first in the post-close window); never co-located with a training run’s eval chain; launch via run_detached.sh with a babysit.toml entry at launch; first-poll util+rate check per standing rule.

Instrument delta (to land, oracle-gated, before launch)

The eligible-list rule lands in the selection layer (SelectedSubgoalPolicy._pick and the offline scorer recomputes in the dump/read path), leaving pass-1 decode and dump bytes untouched; the candidates dump gains the eligible flags and the live filtered picks; the read script (subgoal_draws_results.py family) gains the filter-aware recompute. Oracles (abort-on-red before launch): rung (b)’s (i)–(vi) inherited verbatim — in the draws-0 limit the eligible list is exactly [greedy], so the bit-exact reproduction of the rung-(a) self arm carries; plus (vii) banked-table pick-invariance: re-scoring the real stage-1 table changes 0/60 SC picks and 0/60 ceiling picks (the priors above, as a regression fixture on real data); (viii) the filter binds structurally: a planted fixture whose full-list SC argmax IS a truncated candidate must yield a different filtered pick (and same for the ceiling scorer); (ix) all-truncated fallback: a planted all-9-truncated row yields the greedy candidate as decoded, recorded as a fallback row; (x) the stage-1 re-adjudication script reproduces every written prior above exactly (60/60, 57/60, 23/425, 0/60 + 0/60).