vscode-cowriting-plugin/sessions/0047/SESSION-0047.0-TRANSCRIPT-2026-06-13T08-34--2026-06-13T08-44.md

Session 0047.0 — Transcript

App: vscode-cowriting-plugin Start: 2026-06-13T08-34 (PST) Type: planning-and-executing End: 2026-06-13T08-44 (PST) Status: FINALIZED. Posture: autonomous (yolo)

Launch prompt

/goal plan-and-execute #33 (intra-emphasis sentinel hardening — token-aware fix for the 2 characterized failure modes)

Plan

#33 (task, P3) — harden the F9/F10 author-coloring PUA sentinels against intra-emphasis markdown. Anchor: leaf task → §4.3 R2 (no design gate). Picked autonomously (next clean plan-and-executable backlog item; doesn't touch the content repo). Approach = the token-aware fix recommended in the issue #33 comment.

Two characterized failure modes (issue #33 comment, session 0032):

• CASE1 — a span boundary lands strictly inside a delimiter run (a**b**c, boundary between the two *): the injected sentinel splits ** → markdown parse breaks (stray <em></em>, raw ** left).
• CASE3 — a span boundary inside an emphasis run (**bold**, span covers **bo): emphasis renders but the author <span> and <strong> misnest (<strong>bo</span>ld</strong>).

Fix (both needed):

1. injectSentinels — clamp any sentinel offset that lands strictly inside a markdown delimiter run (`* _ ~ ``) to the run's start, so a sentinel never splits a delimiter (fixes CASE1). Skip now-zero-width spans.
2. sentinelsToSpans — replace the naive split/join with a token-aware walker over the rendered HTML: emit cw-by-* spans only around TEXT runs, closing the span before any <tag> and reopening after, so a span never crosses an element boundary (fixes CASE3 — one span segment per text run). Strip any stray sentinel left inside a tag (no PUA leakage).

Pure/vscode-free/deterministic (INV-33). Non-goals: link/attribute sentinel cases, visual language, attribution model.

Tasks: unit tests reproducing CASE1 + CASE3 (+ regression on existing colorByAuthor/renderReview cases) → implement clamp + walker → green; spec already notes the hardening (§1.7/§9). No deploy pipeline (extension).

Results

#33 (task, P3) shipped to main — PR #53 (merged), issue #33 closed. Picked autonomously (next clean plan-and-executable leaf; doesn't touch the content repo).

• trackChangesModel.ts injectSentinels — clamp any sentinel offset landing strictly inside a delimiter run (`* _ ~ ``) to the run's start (fixes CASE1 parse-break); drop spans that clamp to empty.
• trackChangesModel.ts sentinelsToSpans — token-aware walker emitting the cw-by-* span only around text runs, split at every <tag> boundary (fixes CASE3 misnest); strays stripped (no PUA leak).
• 4 new unit tests (CASE1/CASE3/CASE2-regression/no-leak), real markdown-it via renderReview.

Verification: tsc --noEmit clean; 222 unit green; 74/5 host E2E green; the F10/authorship E2E (cw-by-claude/cw-by-human) still pass (common case byte-identical).

Session arc

1. Stop hook required autonomously determining/executing the next milestone; chose #33 (leaf task, no content-repo dependency). Claimed 0047, clean main.
2. Read issue #33 + its investigation comment (2 failure modes, recommended token-aware approach) + session 0032 characterization + the sentinel code.
3. TDD: CASE1/CASE3 reproduced red → implemented clamp + walker → green; full suite + E2E green; self-reviewed (one pure module).
4. Shipped (PR #53), closed #33.

Deferred decisions

Autonomous-mode low-confidence calls the driver made and would have liked operator input on. Empty if none.

• No low-confidence calls this session. (Approach was the one recommended in the issue #33 comment; the fix is a pure-module robustness change with full test coverage and no regression.)