Authors a 20-case corpus stratified across five geometric failure-mode
families and a separate 10-case benign corpus for the
EXHAUSTION_CEILING lane:
A. near_forbidden_correct_endpoint (6 cases, gaps 0.002 to 0.55)
B. near_equal_admissible (5 cases, diffs ≤ 0.01)
C. no_admissible_path (3 cases, honest refusal)
D. multi_step_admissibility (3 chained cases)
E. heterogeneous_relation (3 chained cases, blade-switching)
phase5_runner runs each case under BOTH threshold and ADR-0026 margin
modes and reports per-family pass_rate, refusal_rate, and (for Family
A) rejection_traced_rate + boundary_overridden_rate.
Headline:
pass_rate_threshold = 1.00 (20/20)
pass_rate_margin = 1.00 (20/20)
mechanism_isolated = true (both modes, all five families)
replay determinism = byte-identical across 3 reruns
Family C refuses with RefusalReason.INNER_LOOP_EXHAUSTION in both
modes (load-bearing evidence for ADR-0024 Phase 2 typed refusals).
Family B refuses under margin mode (validates ADR-0026 δ=0.4 gate).
Benign inner-loop corpus for EXHAUSTION_CEILING ≤ 0.05 gate:
boundary_only: exhaustion 0.00, pass 1.00
null_control: exhaustion 0.00, pass 1.00
inner_loop_t0: exhaustion 0.00, pass 1.00
inner_loop_tpos: exhaustion 0.00, pass 1.00 (threshold 0.25)
Geometric finding documented while authoring the benign corpus:
23 of 85 pack tokens have negative self-cga_inner under Cl(4,1).
Tokens with self-score ≤ 0 cannot serve as single-token expected
endpoints in threshold mode — the algebra's Lorentzian signature
forbids this geometrically. Phase 5 benign corpus draws expected
endpoints from the 62-token positive-self-score subset. This is
consistent with Phase 4 characterization: no static threshold
delivers separation_quality ≥ 0.8 — the margin lane survives
because margin compares differences, not absolute scores.
Files:
evals/forward_semantic_control/public/v2_phase5/cases.jsonl
evals/forward_semantic_control/public/inner_loop_benign/cases.jsonl
evals/forward_semantic_control/phase5_runner.py
evals/forward_semantic_control/phase5_mine.py
evals/forward_semantic_control/results/phase5_report.json
evals/forward_semantic_control/results/phase5_benign_inner_loop_report.json
tests/test_phase5_corpus.py (20 passing)
docs/evals/phase5_stratified_findings.md
Tests: 1068 passed, 2 skipped (+20 from Phase 4 baseline).
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