SubMiner/backlog/tasks/task-315 - Suppress-annotations-for-standalone-じゃない-and-です-ending-tokens.md

---
id: TASK-315
title: Suppress annotations for standalone じゃない and です ending tokens
status: Done
assignee:
  - codex
created_date: '2026-05-03 00:02'
updated_date: '2026-05-03 06:05'
labels:
  - bug
  - tokenizer
dependencies: []
priority: medium
---

## Description

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Standalone `じゃない` grammar ending tokens should not display or persist subtitle annotations even if a dictionary assigns a rank or JLPT/known match. User observed `じゃない` still being marked frequent in overlay after tokenization produced it as a dictionary word.
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## Acceptance Criteria
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- [x] #1 `じゃない` and `です` ending tokens have known-word, N+1, frequency, and JLPT annotation metadata cleared in subtitle annotation output.
- [x] #2 Common polite/question variants such as `じゃないですか` and `ですよ` remain excluded when tokenized as a single ending token.
- [x] #3 Regression coverage proves same-line Yomitan segments split content from trailing grammar endings so the content word can be annotated without coloring the ending.
- [x] #4 Auxiliary-only helper spans such as `てく` + `れた` in `ベアトリスがいてくれたから` have known-word, N+1, frequency, and JLPT annotation metadata cleared.
- [x] #5 Hard-coded grammar-ending phrase permutations are replaced by shared pattern matching, with parser selection and subtitle annotation filtering using the same grammar-ending classifier.
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## Implementation Plan

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1. Add a focused regression for `ベアトリスがいてくれたから` where Yomitan tokens include auxiliary-only `てく` and `れた` with pre-ranked/known/JLPT metadata candidates.
2. Run the targeted test to verify the regression fails before production changes.
3. Patch the shared subtitle annotation filter so kana-only auxiliary helper spans made only of grammar POS components are excluded while preserving lexical content tokens.
4. Re-run targeted tokenizer/annotation tests, then run SubMiner change verification classifier/verifier for the touched files.
5. Update TASK-315 acceptance criteria, notes, and final summary with commands and outcomes.

Replace explicit standalone grammar-ending permutations with a compact shared matcher used by parser selection and annotation filtering.

Add regression tests first for non-enumerated polite copula / ja-nai variants so the matcher behavior is proven, then refactor implementation and verify targeted lanes.
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## Implementation Notes

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Implemented as one focused tokenizer fix. Parser selection now splits dictionary-backed same-line grammar ending segments (`です`, `じゃない*`) from preceding content so annotation styling can apply only to the content token. Shared subtitle annotation filtering now treats bare `です` like the existing `ですか/ですよ/...` copula endings.

2026-05-03: Reopened for approved add-on covering auxiliary-only `てく` + `れた` helper highlighting report.

2026-05-03: Added regression coverage for `ベアトリスがいてくれたから` where Yomitan emits `てく` + `れた` and MeCab enrichment tags `てく` as `助詞|動詞` / `接続助詞|非自立`. The regression initially failed because `てく` kept `isKnown: true` and `jlptLevel: N4`. Added a shared-filter helper for kana-only particle+non-independent-verb helper spans, preserving lexical `自立` verbs. Verification: `bun test src/core/services/tokenizer/annotation-stage.test.ts`, `bun test src/core/services/tokenizer.test.ts`, `bun test src/core/services/tokenizer/parser-selection-stage.test.ts`, `bun x prettier --check ...`, and `bun run typecheck` passed. SubMiner verifier core lane passed typecheck but `bun run test:fast` failed on unrelated existing cross-suite issues: `window.electronAPI` undefined in `src/renderer/handlers/keyboard.ts` during `src/core/services/subsync.test.ts`, followed by Bun `node:test` nested-test cascade.

2026-05-03: Reopened for follow-up requested by user: remove hard-coded standalone grammar-ending permutation list and lean on pattern/POS filtering where possible.

2026-05-03: Added shared `grammar-ending.ts` matcher for polite copula, negative copula, and explanatory endings. Parser selection now uses the standalone-ending matcher instead of `STANDALONE_GRAMMAR_ENDINGS`. Shared subtitle filter now uses the same grammar classifier instead of generated phrase sets. Removed stale duplicate subtitle-exclusion helpers from `annotation-stage.ts`; annotation-stage continues to delegate subtitle exclusion to the shared filter. Verification passed: targeted tokenizer/parser/annotation tests, Prettier check, `bun run typecheck`, `bun run test:fast`, `bun run test:env`, `bun run build`, and `bun run test:smoke:dist`. `bun run changelog:lint` remains blocked by pre-existing malformed fragment `changes/319-interjection-annotation-filter.md`.
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## Final Summary

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Replaced grammar-ending phrase permutations with shared pattern matching. `parser-selection-stage.ts` now splits standalone grammar endings through `grammar-ending.ts` instead of `STANDALONE_GRAMMAR_ENDINGS`; `subtitle-annotation-filter.ts` uses the same classifier for polite copula, negative copula, and explanatory endings instead of generated exact phrase sets.

Kept exclusion ownership cleaner: subtitle annotation exclusion remains in the shared filter, while `annotation-stage.ts` no longer carries stale duplicate subtitle-exclusion constants/helpers. Added regressions for pattern coverage including `ではないですか` splitting and no-POS grammar-ending annotation clearing.

Verification passed: targeted tokenizer/parser/annotation tests, Prettier check, `bun run typecheck`, `bun run test:fast`, `bun run test:env`, `bun run build`, and `bun run test:smoke:dist`. `bun run changelog:lint` is blocked by pre-existing malformed `changes/319-interjection-annotation-filter.md`; new fragment `changes/321-grammar-ending-pattern-filter.md` uses the current metadata format.
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