## Summary
Lexicon-entry closure track per Brief 11D recommendation (Candidate A,
sub-PR 1). Adds 12 drain_token lemmas + 1 alias to `en_core_math_v1`.
`unknown_word` row strictly decreases: **11 → 5** (-6 cases moved past
the first-pass vocabulary gap). `wrong == 0` preserved. `correct` does
not move because admitted=0 (the unblocked cases now refuse at
downstream frames — real new work becoming visible, not regression, per
Brief 11 §Gate 1).
## Additions (all category=drain_token)
| Lemma | Surfaced from |
|-----------|----------------------------|
| along | case 0049 (3rd-wave) |
| animals | case 0040 (3rd-wave) |
| decrease | case 0005 |
| jacks | case 0024 (jumping jacks) |
| length | case 0006 (3rd-wave) |
| previous | case 0006 |
| reach | case 0015 |
| stray | case 0040 |
| too | case 0039 |
| uphill | case 0049 |
| which | case 0001 |
| your | case 0001 (3rd-wave) |
| weight → weights (alias) | case 0021 |
All classified as `drain_token` (the only category that cannot open a
frame and therefore cannot create wrong admissions per Brief 11
§"correct-count greed" doctrine). Reclassifying any as
accumulation/depletion/transfer verbs would risk wrong>0 by opening a
malformed operation_frame.
## wrong=0 verification
- `assert audit_problem(case_0050)` returns `ReaderRefusal` at
sentence_index 0 (pinned by `test_hazard_case_0050_remains_refused_pre_frame`)
- 50-case audit: `admitted=0, refused=50` (pinned by
`test_no_case_admits_after_lexicon_closure`)
- No reader runtime changes; pack-only mutation in a single
per-category source file
- Manifest checksum unchanged: source-file edit doesn't regenerate the
compiled `lexicon.jsonl`; loader reads per-category sources for
alias-aware entries (see `generate/comprehension/lexicon.py:127`)
## Test plan
- 11 new tests in `tests/test_brief_11b_step2_lexicon.py`:
- 4 pack-additions pinning (categories, provenance, aliases, sort order)
- 4 reader-effect / hazard tests (admitted=0, case 0050 refused,
unknown_word row strictly decreased, manifest checksum unchanged)
- 2 loader-integrity tests (new lemmas + aliases resolve through
`load_lexicon` → `lookup`)
- 12 existing tests in `tests/test_brief_11b_audit_artifact.py` pass
(taxonomy counts updated to post-step-2 values)
- 23 existing tests in `tests/test_brief_11_audit.py` pass
## Hard invariants preserved
- `wrong == 0` — no admissions, no frame-opener miscategorisation
- ADR-0166 — no new canonical eval lanes; existing
`gsm8k_math/train_sample/v1/` artifact updated in-place
- No teaching-store mutation; pack mutation is explicit, single-file,
reviewed
- Manifest checksum unchanged (compiled lexicon.jsonl byte-identical)
## Follow-up
- 3 lexicon_entry refusals remain (case 0001 '+', case 0040 'sees',
case 0049 'path'). Not addressed in this PR: '+' is an arithmetic
literal (would change semantics of drain), 'sees' and 'path' have
many other downstream barriers. Address with next-bottleneck PR.
- The 6 cases now refusing at later frames feed directly into Brief
11D Candidate A sub-PR 2 (which bottleneck class to attack next).
66ef4ad07c