Merge origin/main (session 0061 claim) into main

Brings author-colored track changes inline into the main editor (reverses
INV-32): four per-author decoration types, decorateCommitted decorating all
committed changes-since-baseline by author (human green / Claude blue + struck
hints), standalone deletions neutral, proposals recolored Claude, overlap
stacking. Subagent-driven execution of Tasks 6-9; opus whole-branch review +
fix. typecheck + 265 unit + build + E2E green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -8,3 +8,6 @@ test/e2e/fixtures/workspace/.threads/
 
 # Sandbox playground churn (the EDH workspace - play freely, commit nothing)
 sandbox/.threads/
+
+# brainstorming visual-companion scratch
+.superpowers/

docs/superpowers/plans/2026-06-26-author-colored-track-changes.md

@@ -0,0 +1,827 @@
+# Author-colored track changes Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Render every change as a track-changes diff where **style = operation** (underline = inserted, strikethrough = removed) and **color = author** (human green/red, Claude blue/purple), in both the rendered preview pane and the main editor pane.
+
+**Architecture:** Fuse the two color systems that exist today — the *semantic* diff (green=add/red=remove) and the *authorship* tint (cw-by-claude/cw-by-human) — into one author-colored diff. Insertions are colored by their attribution span (data already exists). Deletions are colored by an **adjacency heuristic**: a struck run inherits the author of the insertion it is paired with in the same changed hunk; a standalone removed block falls back to neutral. Phase 1 does this in the pure render engine (preview). Phase 2 reverses INV-32 to bring the same author-colored track changes inline into the editor.
+
+**Tech Stack:** TypeScript, VS Code extension API, `markdown-it`, `diff` (jsdiff), vitest (unit), Playwright/electron host harness (E2E). Render engine (`src/trackChangesModel.ts`) is pure and vscode-free.
+
+## Global Constraints
+
+- **Render engine stays pure / vscode-free / deterministic** — `src/trackChangesModel.ts` must not import `vscode`; same inputs → identical HTML (INV-22).
+- **Author color mapping (verbatim):** human added `#3fb950` / human removed `#f85149` / Claude added `#58a6ff` / Claude removed `#bc8cff`. Insert = 2px underline in the author color + faint author-hued background; remove = line-through in the author color + faint background.
+- **Convention:** underline = inserted, strikethrough = removed, color = author.
+- **"Color means changed since the pinned baseline."** Unchanged-since-baseline text renders plain (no author coloring). The pin→clean behavior (#48) is preserved: a pinned, zero-diff doc renders with no annotation.
+- **Deletion authorship = adjacency heuristic** (locked decision): paired deletions inherit the paired insertion's author; standalone deletions render neutral.
+- **Two roles only:** `human` and `claude` (`AuthorKind`). No arbitrary palettes, no user-configurable colors (YAGNI).
+- **Test command:** `npm test` (vitest, unit). E2E: `npm run test:e2e`. Typecheck: `npm run typecheck`.
+- Commit after each task. Branch off `main` (do not commit to `main` directly).
+
+---
+
+# Phase 1 — Preview pane (independently shippable)
+
+Delivers the full author-colored track-changes language in the rendered preview, where the attribution data already exists.
+
+## File Structure (Phase 1)
+
+- `src/trackChangesModel.ts` — add `authorAt()` + `wordDiffByAuthor()` pure helpers; route the review path through them; color proposal blocks by author; stop coloring unchanged blocks. Add `author?` to `ProposalView`.
+- `src/trackChangesPreview.ts` — pass each proposal's author into its `ProposalView`.
+- `media/preview.css` — author×operation classes; retire the semantic green/red and flat authorship tints.
+- `test/trackChangesModel.test.ts` — new unit tests; update tests asserting old semantic classes.
+
+---
+
+### Task 1: `authorAt()` + `wordDiffByAuthor()` pure helpers
+
+**Files:**
+- Modify: `src/trackChangesModel.ts` (add after `wordMergedMarkdown`, ~line 475)
+- Test: `test/trackChangesModel.test.ts`
+
+**Interfaces:**
+- Consumes: existing `AuthorKind`, `AuthorSpan` (trackChangesModel.ts:557-562), `diffWordsWithSpace` (already imported, line 12).
+- Produces:
+  - `authorAt(offset: number, spans: AuthorSpan[]): AuthorKind | null` — the author whose span covers `offset` (half-open), else null.
+  - `wordDiffByAuthor(beforeRaw: string, afterRaw: string, afterStart: number, spans: AuthorSpan[]): string` — inline HTML where each inserted run is `<ins class="cw-ins-{author}">` (author looked up at the run's `afterStart`-relative landed offset) and each removed run is `<del class="cw-del-{author}">` (author = the insertion it's paired with in the same change cluster; `cw-del-none` if standalone). Unchanged parts are emitted verbatim.
+
+- [ ] **Step 1: Write the failing test**
+
+Add to `test/trackChangesModel.test.ts` (import `authorAt`, `wordDiffByAuthor` from `../src/trackChangesModel`):
+
+```ts
+describe("authorAt", () => {
+  const spans: AuthorSpan[] = [
+    { start: 0, end: 5, author: "human" },
+    { start: 5, end: 10, author: "claude" },
+  ];
+  test("returns the covering span's author (half-open)", () => {
+    expect(authorAt(0, spans)).toBe("human");
+    expect(authorAt(4, spans)).toBe("human");
+    expect(authorAt(5, spans)).toBe("claude");
+    expect(authorAt(9, spans)).toBe("claude");
+  });
+  test("returns null outside any span", () => {
+    expect(authorAt(10, spans)).toBeNull();
+    expect(authorAt(-1, spans)).toBeNull();
+  });
+});
+
+describe("wordDiffByAuthor", () => {
+  test("an inserted run is colored by the author covering its landed offset", () => {
+    // before "hello " ; after "hello brave " ; "brave " inserted at landed offset 6..12
+    const spans: AuthorSpan[] = [{ start: 6, end: 12, author: "claude" }];
+    const html = wordDiffByAuthor("hello ", "hello brave ", 0, spans);
+    expect(html).toContain('<ins class="cw-ins-claude">brave </ins>');
+    expect(html).toContain("hello ");
+  });
+  test("a paired deletion inherits the paired insertion's author (adjacency)", () => {
+    // "light" -> "dark", both in one cluster; "dark" is claude-inserted
+    const spans: AuthorSpan[] = [{ start: 0, end: 4, author: "claude" }];
+    const html = wordDiffByAuthor("light", "dark", 0, spans);
+    expect(html).toContain('<del class="cw-del-claude">light</del>');
+    expect(html).toContain('<ins class="cw-ins-claude">dark</ins>');
+  });
+  test("a standalone deletion (no paired insertion) is neutral", () => {
+    const html = wordDiffByAuthor("keep this word", "keep word", 0, []);
+    expect(html).toContain('<del class="cw-del-none">this </del>');
+    expect(html).not.toContain("cw-del-human");
+    expect(html).not.toContain("cw-del-claude");
+  });
+});
+```
+
+- [ ] **Step 2: Run test to verify it fails**
+
+Run: `npm test -- trackChangesModel`
+Expected: FAIL — `authorAt`/`wordDiffByAuthor` not exported.
+
+- [ ] **Step 3: Write minimal implementation**
+
+Add to `src/trackChangesModel.ts` after `wordMergedMarkdown` (line 475):
+
+```ts
+/** The author whose span covers `offset` (half-open [start,end)), or null. */
+export function authorAt(offset: number, spans: AuthorSpan[]): AuthorKind | null {
+  for (const s of spans) if (offset >= s.start && offset < s.end) return s.author;
+  return null;
+}
+
+const insClass = (a: AuthorKind | null): string => `cw-ins-${a ?? "none"}`;
+const delClass = (a: AuthorKind | null): string => `cw-del-${a ?? "none"}`;
+
+/**
+ * Author-colored word diff for a changed PROSE block in the review.
+ * `afterStart` is the landed-text offset of `afterRaw[0]` so an inserted run's
+ * offset maps into `spans`. Insertions are colored by the author covering their
+ * offset; deletions inherit the author of the insertion they are paired with in
+ * the same contiguous change cluster (adjacency heuristic) — `cw-del-none` when a
+ * cluster has no insertion. Pure, deterministic.
+ */
+export function wordDiffByAuthor(
+  beforeRaw: string,
+  afterRaw: string,
+  afterStart: number,
+  spans: AuthorSpan[],
+): string {
+  const parts = diffWordsWithSpace(beforeRaw, afterRaw);
+  // First pass: find each change cluster's insertion author (first added run).
+  // A cluster is a maximal run of added/removed parts bounded by unchanged parts.
+  let afterOff = afterStart;
+  const clusterAuthor: (AuthorKind | null)[] = []; // per part index, the cluster's del author
+  {
+    let off = afterStart;
+    let i = 0;
+    while (i < parts.length) {
+      const p = parts[i];
+      if (!p.added && !p.removed) {
+        clusterAuthor[i] = null;
+        off += p.value.length;
+        i++;
+        continue;
+      }
+      // a cluster: scan to its end, capturing the first added run's author
+      let j = i;
+      let author: AuthorKind | null = null;
+      let scanOff = off;
+      while (j < parts.length && (parts[j].added || parts[j].removed)) {
+        if (parts[j].added && author === null) author = authorAt(scanOff, spans);
+        if (parts[j].added) scanOff += parts[j].value.length;
+        j++;
+      }
+      for (let k = i; k < j; k++) clusterAuthor[k] = author;
+      off = scanOff;
+      i = j;
+    }
+  }
+  // Second pass: emit.
+  const out: string[] = [];
+  parts.forEach((p, i) => {
+    if (p.added) {
+      const a = authorAt(afterOff, spans);
+      out.push(`<ins class="${insClass(a)}">${p.value}</ins>`);
+      afterOff += p.value.length;
+    } else if (p.removed) {
+      out.push(`<del class="${delClass(clusterAuthor[i] ?? null)}">${p.value}</del>`);
+    } else {
+      out.push(p.value);
+      afterOff += p.value.length;
+    }
+  });
+  return out.join("");
+}
+```
+
+- [ ] **Step 4: Run test to verify it passes**
+
+Run: `npm test -- trackChangesModel`
+Expected: PASS (new describes green).
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add src/trackChangesModel.ts test/trackChangesModel.test.ts
+git commit -m "feat: authorAt + wordDiffByAuthor pure helpers (author-colored word diff w/ adjacency del)"
+```
+
+---
+
+### Task 2: Route the review path through `wordDiffByAuthor`; stop coloring unchanged blocks
+
+**Files:**
+- Modify: `src/trackChangesModel.ts` — `renderReviewOp` (769-780), the `colored` closure + changed-op handling in `renderReview` (889-897)
+- Test: `test/trackChangesModel.test.ts`
+
+**Interfaces:**
+- Consumes: `wordDiffByAuthor` (Task 1), `landedSpans` + `ranges` already computed in `renderReview`.
+- Produces: review HTML where changed prose blocks emit `cw-ins-{author}`/`cw-del-{author}`, added blocks are author-colored as insertions, and **unchanged blocks render plain**.
+
+- [ ] **Step 1: Write the failing test**
+
+Add to the `renderReview` describe in `test/trackChangesModel.test.ts`:
+
+```ts
+test("renderReview: a changed prose block colors ins/del by author (claude replace)", () => {
+  // baseline "light" -> current "dark"; "dark" attributed to claude at 0..4
+  const html = renderReview("light", "dark", [{ start: 0, end: 4, author: "claude" }], []);
+  expect(html).toContain('cw-ins-claude');
+  expect(html).toContain('cw-del-claude'); // adjacency: struck "light" inherits claude
+});
+
+test("renderReview: an unchanged block renders plain (no author coloring)", () => {
+  const doc = "Alpha stays.";
+  const html = renderReview(doc, doc, [{ start: 0, end: 12, author: "human" }], []);
+  expect(html).not.toContain("cw-by-");
+  expect(html).not.toContain("cw-ins-");
+});
+
+test("renderReview: an added block is author-colored as an insertion", () => {
+  // baseline empty-ish -> add a new paragraph authored by human
+  const html = renderReview("Keep.", "Keep.\n\nFresh line.", [{ start: 6, end: 17, author: "human" }], []);
+  expect(html).toContain("cw-ins-human");
+});
+```
+
+- [ ] **Step 2: Run test to verify it fails**
+
+Run: `npm test -- trackChangesModel`
+Expected: FAIL — changed blocks still emit plain `<ins>/<del>` via `wordMergedMarkdown`; unchanged blocks still carry `cw-by-*`.
+
+- [ ] **Step 3: Write minimal implementation**
+
+In `src/trackChangesModel.ts`:
+
+**(a)** Change `renderReviewOp` (769-780) so a changed PROSE block uses author coloring. Give it the colored-insertion path for `added` and the author word-diff for non-atomic `changed`. Replace the function body:
+
+```ts
+function renderReviewOp(
+  op: BlockOp,
+  render: (src: string) => string,
+  colored: (raw: string) => string,
+  src: string,
+  changedHtml?: string,
+): string {
+  // A non-atomic changed prose block is pre-rendered with author-colored ins/del
+  // (changedHtml). Removed blocks and atomic changed fences stay neutral via renderOp
+  // (standalone deletion → neutral, per the adjacency heuristic). `src` is "" for a
+  // removed block (no live source — INV-36).
+  if (op.kind === "changed" && !op.atomic && changedHtml !== undefined) {
+    return `<div class="cw-blk cw-changed"${src}>${changedHtml}</div>`;
+  }
+  if (op.kind === "removed" || op.kind === "changed") return renderOp(op, render, src);
+  return `<div class="cw-blk ${op.kind === "added" ? "cw-added" : "cw-unchanged"}"${src}>${colored(op.block.raw)}</div>`;
+}
+```
+
+**(b)** In `renderReview` (the loop at 889-897), compute the author-colored changed HTML and stop coloring unchanged blocks. Replace the loop body:
+
+```ts
+  let ci = 0; // pointer into ranges; advances for every op with a current-side block
+  const bodyParts: string[] = [];
+  for (const op of ops) {
+    const blockIndex = op.kind === "removed" ? -1 : ci;
+    const blk = op.kind === "removed" ? undefined : ranges[ci++];
+    // Only ADDED blocks are author-colored (they are insertions since baseline);
+    // UNCHANGED blocks render plain (color means "changed since baseline").
+    const colored = (raw: string): string =>
+      blk && !clean && op.kind === "added" ? colorByAuthor(raw, blk.start, landedSpans, render) : render(raw);
+    // A non-atomic changed prose block: author-colored word diff (ins by author,
+    // del by adjacency). `blk.start` is the landed offset of the after-side text.
+    const changedHtml =
+      op.kind === "changed" && !op.atomic && blk && !clean
+        ? render(wordDiffByAuthor(op.before.raw, op.block.raw, blk.start, landedSpans))
+        : undefined;
+    bodyParts.push(renderReviewOp(op, render, colored, srcAttr(blk), changedHtml));
+    const here = blockIndex >= 0 ? byBlock.get(blockIndex) : undefined;
+    if (here) for (const p of here) bodyParts.push(proposalBlockHtml(p, render));
+  }
+  for (const p of trailing) bodyParts.push(proposalBlockHtml(p, render));
+  return bodyParts.join("\n");
+```
+
+> Note: `render(wordDiffByAuthor(...))` passes the HTML-bearing string through markdown-it (same as `wordMergedMarkdown` was rendered). `colorByAuthor` on added blocks emits `cw-by-{author}` spans — Task 4 restyles those to insert styling in CSS.
+
+- [ ] **Step 4: Run test to verify it passes**
+
+Run: `npm test -- trackChangesModel`
+Expected: PASS for the new tests.
+
+- [ ] **Step 5: Update tests that assert the OLD review markup**
+
+Two existing tests assert the old semantic output (test/trackChangesModel.test.ts:226-232). Update them:
+
+```ts
+test("renderReview: human addition since baseline renders author-colored ins", () => {
+  const html = renderReview("hello", "hello world", [{ start: 6, end: 11, author: "human" }], []);
+  expect(html).toContain("cw-ins-human");
+});
+test("renderReview: a standalone deletion since baseline renders neutral struck del", () => {
+  const html = renderReview("hello world", "hello", [], []);
+  expect(html).toMatch(/cw-del-none|cw-removed/);
+});
+```
+
+Run: `npm test -- trackChangesModel`
+Expected: PASS (whole file green).
+
+- [ ] **Step 6: Commit**
+
+```bash
+git add src/trackChangesModel.ts test/trackChangesModel.test.ts
+git commit -m "feat: author-colored changed/added blocks in review; unchanged blocks render plain"
+```
+
+---
+
+### Task 3: Color pending proposal blocks by author
+
+**Files:**
+- Modify: `src/trackChangesModel.ts` — `ProposalView` (731-742) + `proposalBlockHtml` (744-767)
+- Modify: `src/trackChangesPreview.ts` — populate `author` on each `ProposalView`
+- Test: `test/trackChangesModel.test.ts`
+
+**Interfaces:**
+- Consumes: `AuthorKind` (557).
+- Produces: `ProposalView.author?: AuthorKind` (defaults to `"claude"`); `proposalBlockHtml` emits `cw-del-{author}` / `cw-ins-{author}`.
+
+- [ ] **Step 1: Write the failing test**
+
+```ts
+test("renderReview: a proposal block colors its del/ins by author (claude default)", () => {
+  const proposals: ProposalView[] = [{ id: "p1", anchorStart: 0, anchorEnd: 5, replaced: "hello", replacement: "goodbye" }];
+  const html = renderReview("hello", "hello", [], proposals);
+  expect(html).toContain('cw-del-claude');
+  expect(html).toContain('cw-ins-claude');
+});
+```
+
+- [ ] **Step 2: Run test to verify it fails**
+
+Run: `npm test -- trackChangesModel`
+Expected: FAIL — `proposalBlockHtml` still emits `cw-del` / `cw-add`.
+
+- [ ] **Step 3: Write minimal implementation**
+
+In `src/trackChangesModel.ts`, add `author?` to `ProposalView` (after line 741):
+
+```ts
+  /** F12/#64 (INV-48): the pre-apply original, set after optimistic apply. */
+  original?: string;
+  /** Who made the proposal — colors the del/ins. Defaults to "claude". */
+  author?: AuthorKind;
+}
+```
+
+Update `proposalBlockHtml` (753-754):
+
+```ts
+  const who = p.author ?? "claude";
+  const before = p.replaced ? `<del class="cw-del-${who}">${safe(p.replaced)}</del>` : "";
+  const after = `<ins class="cw-ins-${who}">${safe(p.replacement)}</ins>`;
+```
+
+- [ ] **Step 4: Run test to verify it passes**
+
+Run: `npm test -- trackChangesModel`
+Expected: PASS.
+
+- [ ] **Step 5: Populate `author` from the live proposal**
+
+In `src/trackChangesPreview.ts` find where `ProposalView`s are built for `renderReview` (the `listProposals` mapping near line 373). Add `author` from the proposal's provenance. Locate the mapping and add:
+
+```ts
+      author: p.author?.kind === "agent" ? "claude" : "human",
+```
+
+(where `p` is the live `Proposal` with `author: Provenance`). If the preview builds `ProposalView` via a helper, add the field there. Run `npm run typecheck` to confirm the field name matches the live `Proposal.author` shape (`model.ts:79-108`).
+
+- [ ] **Step 6: Run typecheck + tests**
+
+Run: `npm run typecheck && npm test -- trackChangesModel`
+Expected: PASS.
+
+- [ ] **Step 7: Commit**
+
+```bash
+git add src/trackChangesModel.ts src/trackChangesPreview.ts test/trackChangesModel.test.ts
+git commit -m "feat: color pending proposal blocks by author (Claude blue/purple)"
+```
+
+---
+
+### Task 4: CSS — author×operation color system (preview)
+
+**Files:**
+- Modify: `media/preview.css`
+
+**Interfaces:**
+- Consumes: classes emitted by Tasks 1-3: `cw-ins-human|claude|none`, `cw-del-human|claude|none`, `cw-by-human|claude` (added blocks), `cw-added`, `cw-removed`, `cw-changed`, `.cw-proposal`.
+- Produces: the locked color mapping; unchanged text plain.
+
+- [ ] **Step 1: Replace the semantic diff + authorship-tint rules**
+
+In `media/preview.css`, replace lines 21-33 and 55-58 with author-colored rules. New block:
+
+```css
+/* Author-colored track changes — style = operation, color = author.
+   underline = inserted, strikethrough = removed; human green/red, Claude blue/purple. */
+#cw-summary .cw-add { color: #3fb950; }
+#cw-summary .cw-del { color: #f85149; }
+.cw-blk { position: relative; }
+
+/* base ins/del carry the operation; author classes carry the color */
+ins { text-decoration: none; }
+del { text-decoration: line-through; opacity: 0.7; }
+
+.cw-ins-human  { background: rgba(63,185,80,0.14);  border-bottom: 2px solid #3fb950; text-decoration: none; }
+.cw-ins-claude { background: rgba(88,166,255,0.15); border-bottom: 2px solid #58a6ff; text-decoration: none; }
+.cw-ins-none   { background: var(--vscode-diffEditor-insertedTextBackground, rgba(63,185,80,0.14)); text-decoration: none; }
+.cw-del-human  { background: rgba(248,81,73,0.11);  text-decoration: line-through; text-decoration-color: #f85149; }
+.cw-del-claude { background: rgba(188,140,255,0.13); text-decoration: line-through; text-decoration-color: #bc8cff; }
+.cw-del-none   { background: var(--vscode-diffEditor-removedTextBackground, rgba(248,81,73,0.11)); text-decoration: line-through; opacity: 0.7; }
+
+/* whole-block ops: an added block is an insertion (author-colored inside via cw-by-*);
+   a standalone removed block is neutral struck (adjacency heuristic fallback) */
+.cw-added   { background: transparent; }
+.cw-removed { background: var(--vscode-diffEditor-removedTextBackground, rgba(248,81,73,0.10)); text-decoration: line-through; opacity: 0.65; }
+.cw-changed { outline: none; }
+
+/* added-block author runs (colorByAuthor sentinels) read as insertions */
+.cw-by-human  { background: rgba(63,185,80,0.14);  border-bottom: 2px solid #3fb950; text-decoration: none; }
+.cw-by-claude { background: rgba(88,166,255,0.15); border-bottom: 2px solid #58a6ff; text-decoration: none; }
+.cw-blk.cw-by-claude, .cw-blk.cw-by-human, .cw-blk.cw-mixed { outline: 2px solid currentColor; outline-offset: 2px; background: transparent; }
+#cw-legend .cw-swatch { padding: 0 0.4em; border-radius: 3px; }
+#cw-summary .cw-prop { opacity: 0.85; }
+```
+
+- [ ] **Step 2: Recolor the proposal block accent to neutral (author lives inside it now)**
+
+The proposal block's left border is currently blue (`--vscode-charts-blue`). Keep it as a neutral "pending" frame — the del/ins inside now carry the author color. Change `media/preview.css:79-80`:
+
+```css
+  border-left: 3px solid var(--vscode-panel-border, #555);
+  background: color-mix(in srgb, var(--vscode-foreground) 5%, transparent);
+```
+
+- [ ] **Step 3: Manual visual verification**
+
+Run the extension host (or load the smoke doc) and confirm in the preview: human insertions green-underlined, Claude insertions blue-underlined, Claude deletions purple-struck, standalone deletions neutral, unchanged text plain.
+
+Run: `npm run build`
+Expected: builds clean (CSS is bundled into the webview assets per the build).
+
+- [ ] **Step 4: Commit**
+
+```bash
+git add media/preview.css
+git commit -m "feat: author-colored track-changes CSS for the preview (human green/red, Claude blue/purple)"
+```
+
+---
+
+### Task 5: Phase-1 host E2E — author colors render in the preview
+
+**Files:**
+- Test: the existing F10/F7 preview E2E suite (find under `test/e2e/` — the preview/review specs)
+
+**Interfaces:**
+- Consumes: the rendered preview webview HTML.
+
+- [ ] **Step 1: Write the failing E2E assertions**
+
+In the preview E2E spec, after producing a Claude change + a human change on a doc, assert the webview body contains `cw-ins-claude` and `cw-ins-human`, and that an unchanged paragraph has no `cw-ins-`/`cw-by-` class. (Follow the existing pattern in that spec for opening the preview and reading `panel.webview` HTML or the DOM via the harness.)
+
+- [ ] **Step 2: Run to verify it fails (or update an assertion that checked old classes)**
+
+Run: `npm run test:e2e`
+Expected: FAIL if any existing assertion checked `cw-add`/`cw-by-*`-as-authorship; update those to the new classes.
+
+- [ ] **Step 3: Make it pass**
+
+Adjust any E2E assertion referencing retired classes (`cw-add`, semantic `ins`/`del` colors, `cw-by-*` on unchanged blocks) to the new author classes.
+
+Run: `npm run test:e2e`
+Expected: PASS.
+
+- [ ] **Step 4: Commit**
+
+```bash
+git add test/e2e
+git commit -m "test(e2e): assert author-colored track changes render in the preview"
+```
+
+**>>> Phase 1 is independently shippable here. Open a PR for the preview pane before starting Phase 2, or continue.**
+
+---
+
+# Phase 2 — Editor pane (reverses INV-32)
+
+Brings the same author-colored track changes inline into the main editor: all changes-since-baseline (committed + pending), not just pending proposals.
+
+## File Structure (Phase 2)
+
+- `src/editorProposalController.ts` — per-author decoration types; recolor proposals; subscribe to baseline + attribution; decorate all committed insertions (author-colored) + committed deletion hints (adjacency); overlap stacks naturally.
+- `src/extension.ts` — inject `DiffViewController` + `AttributionController` into `EditorProposalController`.
+- Test: editor E2E suite.
+
+---
+
+### Task 6: Per-author decoration types; recolor proposals to Claude
+
+**Files:**
+- Modify: `src/editorProposalController.ts` (20-27 decoration types; 80-106 renderEditor)
+- Test: editor E2E
+
+**Interfaces:**
+- Consumes: `decorationPlan` (already imported), proposal list.
+- Produces: four insertion decoration types (`human`/`claude`) keyed by author, deletion-hint types colored by author; proposals decorate with Claude colors.
+
+- [ ] **Step 1: Replace the two decoration types with per-author maps**
+
+In `src/editorProposalController.ts`, replace lines 20-27:
+
+```ts
+  private readonly insDeco: Record<"human" | "claude", vscode.TextEditorDecorationType> = {
+    human: vscode.window.createTextEditorDecorationType({
+      backgroundColor: "rgba(63,185,80,0.14)", borderColor: "#3fb950",
+      border: "0 0 2px 0", borderStyle: "solid",
+    }),
+    claude: vscode.window.createTextEditorDecorationType({
+      backgroundColor: "rgba(88,166,255,0.15)", borderColor: "#58a6ff",
+      border: "0 0 2px 0", borderStyle: "solid",
+    }),
+  };
+  private readonly delDeco: Record<"human" | "claude", vscode.TextEditorDecorationType> = {
+    human: vscode.window.createTextEditorDecorationType({ after: { color: "#f85149" } }),
+    claude: vscode.window.createTextEditorDecorationType({ after: { color: "#bc8cff" } }),
+  };
+```
+
+Update the constructor's disposables push (39-40) to dispose all four:
+
+```ts
+      this.insDeco.human, this.insDeco.claude, this.delDeco.human, this.delDeco.claude, this.lensEmitter,
+```
+
+- [ ] **Step 2: Recolor proposal decorations to Claude in `renderEditor`**
+
+Replace the body of `renderEditor` (81-106) so it groups ranges per author and applies the right decoration type. Proposals are Claude:
+
+```ts
+  private renderEditor(editor: vscode.TextEditor): void {
+    const doc = editor.document;
+    const clearAll = () => {
+      for (const a of ["human", "claude"] as const) {
+        editor.setDecorations(this.insDeco[a], []);
+        editor.setDecorations(this.delDeco[a], []);
+      }
+    };
+    if (doc.languageId !== "markdown") return clearAll();
+    const key = this.proposals.keyFor(doc);
+    const ins: Record<"human" | "claude", vscode.Range[]> = { human: [], claude: [] };
+    const del: Record<"human" | "claude", vscode.DecorationOptions[]> = { human: [], claude: [] };
+    // Pending proposals — always Claude (INV: proposals are agent-authored).
+    for (const v of this.proposals.listProposals(doc)) {
+      if (v.anchorStart === null || v.original === undefined || !this.proposals.isApplied(key, v.id)) continue;
+      const plan = decorationPlan(v.anchorStart, v.original, v.replacement);
+      for (const i of plan.insertions) ins.claude.push(new vscode.Range(doc.positionAt(i.start), doc.positionAt(i.end)));
+      for (const d of plan.deletions) {
+        del.claude.push({
+          range: new vscode.Range(doc.positionAt(d.at), doc.positionAt(d.at)),
+          renderOptions: { after: { contentText: ` ${d.text} `, textDecoration: "line-through" } },
+        });
+      }
+    }
+    // Committed changes-since-baseline are added in Task 7 (pushes into ins/del[author]).
+    this.decorateCommitted(editor, ins, del); // no-op stub until Task 7
+    for (const a of ["human", "claude"] as const) {
+      editor.setDecorations(this.insDeco[a], ins[a]);
+      editor.setDecorations(this.delDeco[a], del[a]);
+    }
+  }
+
+  /** Overridden in Task 7 to add committed (non-proposal) author-colored changes. */
+  private decorateCommitted(
+    _editor: vscode.TextEditor,
+    _ins: Record<"human" | "claude", vscode.Range[]>,
+    _del: Record<"human" | "claude", vscode.DecorationOptions[]>,
+  ): void {}
+```
+
+- [ ] **Step 3: Typecheck + build**
+
+Run: `npm run typecheck && npm run build`
+Expected: clean.
+
+- [ ] **Step 4: E2E — proposal shows Claude colors**
+
+Update/extend the editor E2E to assert a pending proposal decorates (smoke: the decoration types exist and apply; the harness asserts via the proposal-applied path used today). Run: `npm run test:e2e` → PASS.
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add src/editorProposalController.ts test/e2e
+git commit -m "feat: per-author editor decoration types; proposals decorate in Claude blue/purple"
+```
+
+---
+
+### Task 7: Decorate committed changes-since-baseline by author (reverse INV-32)
+
+**Files:**
+- Modify: `src/editorProposalController.ts` — inject baseline + attribution; implement `decorateCommitted`; subscribe to baseline/attribution change events
+- Modify: `src/extension.ts` (line 122) — pass the two new deps
+- Test: editor E2E
+
+**Interfaces:**
+- Consumes: `DiffViewController.getBaseline(uri)` (diffViewController.ts:133) + `onDidChangeBaseline` (32); `AttributionController.spansFor(document)` (attributionController.ts:405); pure `wordEditHunks` + `authorAt` (trackChangesModel.ts).
+- Produces: committed insertions colored by `authorAt(currentOffset)`; committed deletion hints colored by adjacency (the paired insertion's author).
+
+- [ ] **Step 1: Inject the new dependencies**
+
+Change the constructor signature (38):
+
+```ts
+  constructor(
+    private readonly proposals: ProposalController,
+    private readonly diffView: import("./diffViewController").DiffViewController,
+    private readonly attribution: import("./attributionController").AttributionController,
+  ) {
+```
+
+Add subscriptions in the constructor disposables list:
+
+```ts
+      this.diffView.onDidChangeBaseline(({ uri }) => {
+        const ed = vscode.window.visibleTextEditors.find((e) => e.document.uri.toString() === uri);
+        if (ed) this.renderEditor(ed);
+      }),
+```
+
+In `src/extension.ts` (122) pass the deps (both already constructed above — `diffViewController` and `attributionController`):
+
+```ts
+  const editorProposalController = new EditorProposalController(
+    proposalController,
+    diffViewController,
+    attributionController,
+  );
+```
+
+(Confirm the local variable names in `extension.ts` for the diff-view + attribution controllers via `npm run typecheck`.)
+
+- [ ] **Step 2: Implement `decorateCommitted`**
+
+Replace the stub with the real implementation. It diffs baseline → current, attributes insertions, and colors deletion hints by adjacency:
+
+```ts
+  private decorateCommitted(
+    editor: vscode.TextEditor,
+    ins: Record<"human" | "claude", vscode.Range[]>,
+    del: Record<"human" | "claude", vscode.DecorationOptions[]>,
+  ): void {
+    const doc = editor.document;
+    const baseline = this.diffView.getBaseline(doc.uri.toString());
+    if (!baseline || baseline.reason === "pinned") return; // pin→clean: no committed marks
+    const current = doc.getText();
+    const spans = this.attribution.spansFor(doc); // AuthorSpan[] in current coords
+    const hunks = wordEditHunks(baseline.text, current); // start/end index INTO current
+    for (const h of hunks) {
+      // The replacement text occupies [h.start, h.start+replacement.length) in current.
+      // Re-derive the intra-hunk word diff to split ins vs del and find the author.
+      const original = baseline.text.slice(/* mapped */ 0, 0); // see note
+      const plan = decorationPlan(h.start, hunkOriginal(baseline.text, current, h), current.slice(h.start, h.end));
+      const author = authorAt(h.start, spans) ?? "human";
+      for (const i of plan.insertions) ins[author].push(new vscode.Range(doc.positionAt(i.start), doc.positionAt(i.end)));
+      for (const d of plan.deletions) {
+        del[author].push({
+          range: new vscode.Range(doc.positionAt(d.at), doc.positionAt(d.at)),
+          renderOptions: { after: { contentText: ` ${d.text} `, textDecoration: "line-through" } },
+        });
+      }
+    }
+  }
+```
+
+> **Implementation note for the engineer:** `wordEditHunks(baseline, current)` returns hunks whose `start`/`end` index into **current** with a `replacement` that is the *baseline* text for that span (see trackChangesModel.ts:241-264 — `replacement` accumulates `removed` parts = baseline text, `end` advances over them). So for a committed change, the *original* (baseline) text of a hunk is `h.replacement` and the *applied* (current) text is `current.slice(h.start, h.end)`. Call `decorationPlan(h.start, h.replacement, current.slice(h.start, h.end))` directly — drop the `hunkOriginal`/`original` placeholder lines above. Verify this against a unit test before wiring (Step 3).
+
+- [ ] **Step 3: Unit-test the hunk→plan derivation (pure)**
+
+Because the offset semantics are subtle, add a pure unit test in `test/trackChangesModel.test.ts` proving `wordEditHunks` + `decorationPlan` reconstruct a committed change. Add an exported helper if needed:
+
+```ts
+test("committed change: wordEditHunks replacement is baseline text; current slice is applied", () => {
+  const baseline = "the light mode";
+  const current = "the dark mode";
+  const [h] = wordEditHunks(baseline, current);
+  expect(h.replacement).toContain("light");          // baseline side
+  expect(current.slice(h.start, h.end)).toContain("dark"); // applied side
+  const plan = decorationPlan(h.start, h.replacement, current.slice(h.start, h.end));
+  expect(plan.insertions.length).toBeGreaterThan(0);
+  expect(plan.deletions.some((d) => d.text.includes("light"))).toBe(true);
+});
+```
+
+Run: `npm test -- trackChangesModel` → PASS. Then finalize `decorateCommitted` to use `h.replacement` + `current.slice(h.start, h.end)` (removing the placeholder lines).
+
+- [ ] **Step 4: Add the attribution-change refresh**
+
+Editor decorations must refresh when attribution changes (e.g. after a human edit). If `AttributionController` exposes a change event, subscribe to it and call `renderEditor`; otherwise refresh on `vscode.workspace.onDidChangeTextDocument` for the active editor (debounced like `scheduleApply`). Add to the constructor disposables:
+
+```ts
+      vscode.workspace.onDidChangeTextDocument((e) => {
+        const ed = vscode.window.activeTextEditor;
+        if (ed && e.document === ed.document) this.scheduleRender(ed);
+      }),
+```
+
+with a small `scheduleRender(ed)` that debounces `renderEditor(ed)` (mirror `scheduleApply`, 50ms).
+
+- [ ] **Step 5: Typecheck + build + E2E**
+
+Run: `npm run typecheck && npm run build && npm run test:e2e`
+Expected: clean. E2E: a committed human edit shows green underline; an accepted Claude replace shows blue underline + purple struck hint; a pinned baseline shows nothing.
+
+- [ ] **Step 6: Commit**
+
+```bash
+git add src/editorProposalController.ts src/extension.ts test/trackChangesModel.test.ts test/e2e
+git commit -m "feat: author-colored committed track changes inline in the editor (reverse INV-32)"
+```
+
+---
+
+### Task 8: Overlap — stacked marks where both authors touch one span
+
+**Files:**
+- Test: `test/trackChangesModel.test.ts` (preview overlap) + editor E2E (editor overlap)
+- Modify (if needed): `media/preview.css` (ensure `<ins>` nested in `<del>` and vice-versa render both marks)
+
+**Interfaces:**
+- Consumes: existing emitted classes.
+- Produces: a span both inserted (author A) and being deleted (author B) shows both A's underline and B's strikethrough.
+
+- [ ] **Step 1: Editor overlap — verify decorations stack**
+
+In the editor, an overlap arises when a committed insertion range (author A) is also covered by a pending proposal deletion (Claude). VS Code applies multiple decoration types to overlapping ranges, so the author-A insertion underline and the Claude deletion hint already coexist. Add an editor E2E asserting both decoration types are present on the overlap region. No code change expected; if the proposal's optimistic apply *replaces* the text (so A's range no longer exists), document that committed-insert + pending-delete overlap manifests as the proposal's struck original (Claude purple) adjacent to A's surviving insertion — assert that instead.
+
+- [ ] **Step 2: Preview overlap — CSS nesting**
+
+Add a CSS test fixture / assertion: a `<del class="cw-del-claude"><span class="cw-ins-human">…</span></del>` renders with both strikethrough (Claude purple) and underline (human green). Add to `media/preview.css` if the nested case collapses:
+
+```css
+.cw-del-claude .cw-ins-human, .cw-del-human .cw-ins-claude,
+.cw-del-claude .cw-by-human,  .cw-del-human .cw-by-claude { text-decoration: inherit; }
+```
+
+- [ ] **Step 3: Run tests**
+
+Run: `npm test && npm run test:e2e`
+Expected: PASS.
+
+- [ ] **Step 4: Commit**
+
+```bash
+git add media/preview.css test/trackChangesModel.test.ts test/e2e
+git commit -m "feat: overlap renders stacked author marks (insert + delete) in both panes"
+```
+
+---
+
+### Task 9: Sweep retired markup + full suite + manual smoke
+
+**Files:**
+- `test/**`, `media/preview.css`, any code referencing retired classes.
+
+- [ ] **Step 1: Grep for retired classes/behaviors**
+
+Run:
+```bash
+grep -rn "cw-add\b\|cw-del\b\|diffEditor.insertedTextBackground\|gitDecoration.deletedResourceForeground" src/ media/ test/
+```
+Reconcile every hit: `cw-add`/`cw-del` (without `-author`) only legitimately remain in `#cw-summary`. The editor's old semantic ThemeColors are gone (replaced in Task 6).
+
+- [ ] **Step 2: Full unit + typecheck + build**
+
+Run: `npm run typecheck && npm test && npm run build`
+Expected: all green.
+
+- [ ] **Step 3: Full E2E**
+
+Run: `npm run test:e2e`
+Expected: all green (update any remaining old-class assertions).
+
+- [ ] **Step 4: Manual smoke (both panes)**
+
+Open the sandbox doc, make a human edit + ask Claude to edit. Confirm: editor shows green/blue underlines + purple/red struck hints; preview shows the same; unchanged text plain in both; pin baseline → both panes clean; accept a proposal → it recolors as a committed change until re-pin.
+
+- [ ] **Step 5: Commit + open PR**
+
+```bash
+git add -A
+git commit -m "chore: sweep retired semantic-diff markup; full suite green"
+```
+
+---
+
+## Self-Review
+
+**1. Spec coverage:**
+- Model (style=op, color=author) → Tasks 1-4 (preview), 6-7 (editor). ✓
+- Human green/red + Claude blue/purple, exact hexes → Global Constraints + Task 4 CSS + Task 6 decorations. ✓
+- Both panes → Phase 1 (preview) + Phase 2 (editor). ✓
+- Reverses INV-32 → Task 7. ✓
+- Both overlap directions, stacked → Task 8. ✓
+- Color = changed-since-baseline; pin→clean preserved → Task 2 (unchanged plain), Task 7 (`reason === "pinned"` guard). ✓
+- Deletion authorship = adjacency heuristic; standalone neutral → Task 1 (`wordDiffByAuthor` cluster author + `cw-del-none`), Task 7 (`authorAt(h.start)`). ✓
+- Components: trackChangesModel, editorProposalController, attributionController (read via spansFor), preview.css, extension.ts wiring → covered. ✓
+- Testing: unit (pure render), editor decorations (E2E), host E2E, retire old assertions → Tasks 1-3, 5, 7-9. ✓
+
+**2. Placeholder scan:** Task 7 Step 2 intentionally shows a *wrong* placeholder (`hunkOriginal`/`original`) and immediately corrects it in the implementation note + Step 3 unit test that pins the exact offsets — this is a guided derivation, not an unresolved placeholder. No other TBD/TODO.
+
+**3. Type consistency:** `AuthorKind` (`"claude" | "human"`) used throughout; decoration maps keyed `"human" | "claude"`; `authorAt` returns `AuthorKind | null` → `?? "human"`/`?? "none"` at every call site; `ProposalView.author?: AuthorKind`; `wordDiffByAuthor(beforeRaw, afterRaw, afterStart, spans)` signature matches both its test and its `renderReview` call site.
+
+## Execution Handoff
+
+(Filled in after you review.)

docs/superpowers/specs/2026-06-26-author-colored-track-changes-design.md

@@ -0,0 +1,150 @@
+# Author-colored track changes (both panes) — design
+
+**Date:** 2026-06-26
+**Status:** Design approved; ready for implementation planning
+**Mockups:** `.superpowers/brainstorm/15095-1782504559/content/panes-states-v2.html`
+
+## Problem
+
+Today the plugin uses two unrelated color systems:
+
+- **The diff** (proposed/changed text in both panes) uses *semantic* colors —
+  green = added, red = removed — regardless of who made the change.
+- **Authorship** (F3) uses *author* colors (blue = Claude, green = human) but
+  only as a flat tint in the **preview** pane, and only on committed text, not
+  as a diff.
+
+So you cannot look at a change and immediately see **who** made it. The product
+goal is an experience like two humans collaborating in a track-changes document
+(Google Docs suggesting mode / Word track changes): every edit is a diff, and a
+glance tells you both *what changed* and *who changed it*.
+
+## The model
+
+Every change is rendered as a diff — insertions **and** deletions — where:
+
+- **Style encodes the operation:** underline = inserted, strikethrough = removed.
+- **Color encodes the author.**
+
+|        | Added            | Removed                |
+| ------ | ---------------- | ---------------------- |
+| Human  | green underline  | red strikethrough      |
+| Claude | blue underline   | purple strikethrough   |
+
+Human keeps today's exact green/red. Claude gets blue/purple (blue is already
+Claude's established attribution hue; purple reads as a removal without colliding
+with human red).
+
+**Color means "changed since the pinned baseline,"** not "authored forever." Once
+a change is accepted and the baseline re-pins, its marks clear and the text
+returns to plain. This preserves the existing pin→clean behavior (#48): a pinned,
+zero-diff document renders with no annotation.
+
+### Concrete colors
+
+Carry the existing human values; add Claude's pair. (Final hex values are a
+polish detail for implementation; these are the design intent.)
+
+- Human added: `#3fb950` underline, bg `rgba(63,185,80,0.14)`
+- Human removed: `#f85149` strikethrough, bg `rgba(248,81,73,0.11)`
+- Claude added: `#58a6ff` underline, bg `rgba(88,166,255,0.15)`
+- Claude removed: `#bc8cff` strikethrough, bg `rgba(188,140,255,0.13)`
+
+Each change run is a subtle author-hued background tint **plus** a solid 2px
+underline (insert) or strikethrough (delete) in the full author color — the solid
+line carries the signal even where backgrounds are faint.
+
+## Both panes (decision A)
+
+Author-colored track changes appear in **both** the main editor pane and the
+rendered preview pane.
+
+- **Main editor pane:** gains full inline track-changes for *all*
+  changes-since-baseline — human and Claude, committed and pending — not just
+  pending proposals. **This reverses INV-32** ("editor fully clean") from F10:
+  the editor was deliberately kept clean, with all who-wrote-what coloring living
+  only in the preview. We are intentionally undoing that.
+- **Rendered preview pane:** shows the same model (it already renders a diff +
+  authorship; this unifies them so ins/del runs are author-colored rather than
+  semantically colored).
+
+Pending Claude proposals keep their Accept/Reject affordance in both panes —
+CodeLens (`✓ Accept ▾ / ✗ Reject ▾`) in the editor, buttons in the preview.
+
+## States (must all render correctly)
+
+Base states: human-added, human-removed, Claude-added, Claude-removed.
+
+**Overlap** — a single span both authors touched — stacks both marks:
+
+- Human added it, Claude is removing it → green underline **+** purple strikethrough.
+- Claude added it, human is removing it → blue underline **+** red strikethrough.
+
+Block-level: a whole added block carries the author's add treatment (left border +
+tint); a whole removed block carries the author's remove treatment (struck + tint).
+
+Resting state: unchanged-since-baseline text renders plain. After Accept + re-pin,
+changed text returns to plain.
+
+## Architecture
+
+The core change is **fusing the currently-separate semantic-diff and authorship
+systems** so that every inserted/deleted run carries its author, and rendering
+colors by that author rather than by add/remove semantics.
+
+Components affected (per the current code map):
+
+- **`src/trackChangesModel.ts`** — `renderReview` / `renderOp` /
+  `wordMergedMarkdown` / `colorByAuthor`. Today `<ins>`/`<del>` are emitted with
+  semantic green/red classes independent of author. Change: ins/del runs become
+  author-aware and emit author-colored classes; overlap emits a stacked-mark
+  class.
+- **`src/editorProposalController.ts`** — today only pending proposals decorate,
+  using semantic `ThemeColor`s. Change: per-author/op `TextEditorDecorationType`s
+  (human-add/human-del/claude-add/claude-del + overlap), and decorate **all**
+  changes-since-baseline, not just proposals (the INV-32 reversal).
+- **`src/attributionController.ts`** — supplies the per-character/per-run author
+  spans the diff needs to attribute insertions (and, see below, deletions).
+- **`media/preview.css`** — recolor: keep human green/red, add Claude
+  blue/purple, encode underline=insert / strikethrough=delete, add overlap
+  (stacked-mark) classes for both directions.
+
+## Open technical question (for the plan / tech-design stage)
+
+**Deletion authorship.** Removed text is no longer in the buffer, so the renderer
+must know *who deleted it* to color the strikethrough.
+
+- For **pending proposals**, the deleter is trivially Claude (the proposal owns
+  the deletion).
+- For **committed deletions** (baseline → current), we must confirm the F3 seam /
+  attribution model carries the **deleting actor**. F3 attributes
+  *current-buffer* characters; deleted characters are gone. If the seam's edit
+  events carry the actor that performed each removal, we attribute from that; if
+  not, deriving deletion authorship is the main thing the implementation plan has
+  to solve. Until resolved, a safe fallback is to color committed deletions by the
+  **turn actor** that produced the diff hunk.
+
+This is the one genuinely open architectural item; everything else is
+presentation.
+
+## Out of scope (YAGNI)
+
+- More than two authors / arbitrary per-collaborator palettes. Two roles
+  (human, Claude) only.
+- User-configurable colors / theme settings. Ship one good scheme.
+- Changing accept/reject *mechanics* — this is purely how changes are
+  **visualized**; the F4 proposal lifecycle is unchanged.
+- Per-word authorship inside an accepted, re-pinned (plain) document.
+
+## Testing
+
+- **Unit (pure render):** `trackChangesModel` renders each state to the expected
+  author-colored markup — the four base states, both overlap directions, block
+  add/remove, and resting/plain. Reuse the existing pure-render test pattern.
+- **Editor decorations:** the decoration plan produces the right per-author/op
+  ranges, including the INV-32-reversal (committed changes now decorate) and
+  stacked overlap ranges.
+- **Host E2E:** open a co-edited doc, assert both panes show author-colored
+  marks; accept a proposal + re-pin → marks clear (pin→clean preserved).
+- Update/replace any test that asserts the **old** semantic green=add/red=remove
+  classes or the INV-32 clean-editor behavior.

media/preview.css

@@ -18,19 +18,40 @@ body {
   display: flex;
   gap: 1rem;
 }
-#cw-summary .cw-add { color: var(--vscode-gitDecoration-addedResourceForeground); }
-#cw-summary .cw-del { color: var(--vscode-gitDecoration-deletedResourceForeground); }
+/* Author-colored track changes — style = operation, color = author.
+   underline = inserted, strikethrough = removed; human green/red, Claude blue/purple. */
+#cw-summary .cw-add { color: #3fb950; }
+#cw-summary .cw-del { color: #f85149; }
 .cw-blk { position: relative; }
-ins, .cw-added {
-  background: var(--vscode-diffEditor-insertedTextBackground, rgba(0, 255, 0, 0.15));
-  text-decoration: none;
-}
-del, .cw-removed {
-  background: var(--vscode-diffEditor-removedTextBackground, rgba(255, 0, 0, 0.15));
-  text-decoration: line-through;
-  opacity: 0.7;
-}
-.cw-changed { outline: 2px solid var(--vscode-diffEditor-insertedTextBackground, rgba(0, 255, 0, 0.25)); outline-offset: 2px; }
+
+/* base ins/del carry the operation; author classes carry the color */
+ins { text-decoration: none; }
+del { text-decoration: line-through; opacity: 0.7; }
+
+.cw-ins-human  { background: rgba(63,185,80,0.14);  border-bottom: 2px solid #3fb950; text-decoration: none; }
+.cw-ins-claude { background: rgba(88,166,255,0.15); border-bottom: 2px solid #58a6ff; text-decoration: none; }
+.cw-ins-none   { background: var(--vscode-diffEditor-insertedTextBackground, rgba(63,185,80,0.14)); text-decoration: none; }
+.cw-del-human  { background: rgba(248,81,73,0.11);  text-decoration: line-through; text-decoration-color: #f85149; }
+.cw-del-claude { background: rgba(188,140,255,0.13); text-decoration: line-through; text-decoration-color: #bc8cff; }
+.cw-del-none   { background: var(--vscode-diffEditor-removedTextBackground, rgba(248,81,73,0.11)); text-decoration: line-through; opacity: 0.7; }
+
+/* Task 8 — overlap: if a future render path nests cw-ins-{A} inside cw-del-{B},
+   both marks must show. cw-ins-* sets text-decoration:none which would otherwise
+   suppress the parent del's strikethrough. `inherit` restores the parent's
+   line-through while the child's border-bottom underline is unaffected.
+   The engine currently emits SIBLING ins/del (never nested) so this rule is a
+   forward defensive guarantee only. See task-8-report.md for details. */
+.cw-del-claude .cw-ins-human, .cw-del-human .cw-ins-claude { text-decoration: inherit; }
+
+/* whole-block ops: an added block is an insertion (its author runs are emitted as
+   cw-ins-* via colorByAuthor with kind="ins"); a standalone removed block is neutral
+   struck (adjacency heuristic fallback) */
+.cw-added   { background: transparent; }
+.cw-removed { background: var(--vscode-diffEditor-removedTextBackground, rgba(248,81,73,0.10)); text-decoration: line-through; opacity: 0.65; }
+.cw-changed { outline: none; }
+
+#cw-legend .cw-swatch { padding: 0 0.4em; border-radius: 3px; }
+#cw-summary .cw-prop { opacity: 0.85; }
 .cw-badge {
   position: absolute;
   top: 0;
@@ -52,12 +73,6 @@ del, .cw-removed {
 pre.mermaid { text-align: center; background: transparent; }
 pre.mermaid[data-cw-error] { color: var(--vscode-errorForeground); }
 
-/* F9 authorship mode — inline author tints + block-level fence badges + toggle. */
-.cw-by-claude { background: var(--vscode-editorInfo-foreground, rgba(64, 120, 242, 0.18)); text-decoration: none; }
-.cw-by-human { background: var(--vscode-gitDecoration-addedResourceForeground, rgba(46, 160, 67, 0.18)); text-decoration: none; }
-.cw-blk.cw-by-claude, .cw-blk.cw-by-human, .cw-blk.cw-mixed { outline: 2px solid currentColor; outline-offset: 2px; background: transparent; }
-#cw-legend .cw-swatch { padding: 0 0.4em; border-radius: 3px; }
-#cw-summary .cw-prop { opacity: 0.85; }
 
 /* F11 — preview toolbar buttons (Pin baseline; adaptive Ask Claude). Theme-aware. */
 #cw-header button {
@@ -76,8 +91,8 @@ pre.mermaid[data-cw-error] { color: var(--vscode-errorForeground); }
 #cw-toggle { display: inline-flex; align-items: center; gap: 0.35em; cursor: pointer; }
 .cw-proposal {
   position: relative;
-  border-left: 3px solid var(--vscode-charts-blue, #4daafc);
-  background: color-mix(in srgb, var(--vscode-charts-blue, #4daafc) 12%, transparent);
+  border-left: 3px solid var(--vscode-panel-border, #555);
+  background: color-mix(in srgb, var(--vscode-foreground) 5%, transparent);
   padding: 0.4em 0.6em; margin: 0.4em 0; border-radius: 3px;
 }
 .cw-proposal-unanchored { border-left-style: dashed; opacity: 0.85; }

src/editorProposalController.ts

@@ -7,24 +7,34 @@
  * for deletions (INV-52, decorationPlan/INV-49), and (3) provides a CodeLens
  * `Accept ▾ / Reject ▾` above each block whose ▾ opens a QuickPick (this / all).
  * Owns no proposal STATE — it is a view over ProposalController (which stays the
- * pure F4 owner). A document with no pending proposals shows nothing (INV-32's
- * spirit when nothing is pending).
+ * pure F4 owner). Phase 2 decorates ALL committed changes-since-baseline by author
+ * (human green / Claude blue + struck hints for deletions), plus pending proposals;
+ * a pinned baseline suppresses committed marks entirely (pin→clean, INV-48).
  */
 import * as vscode from "vscode";
 import type { ProposalController } from "./proposalController";
-import { decorationPlan } from "./trackChangesModel";
+import type { DiffViewController } from "./diffViewController";
+import type { AttributionController } from "./attributionController";
+import { decorationPlan, wordEditHunks, authorAt } from "./trackChangesModel";
 import { isAuthorable } from "./workspacePath";
 
 export class EditorProposalController implements vscode.Disposable, vscode.CodeLensProvider {
   private readonly disposables: vscode.Disposable[] = [];
-  private readonly insertionDeco = vscode.window.createTextEditorDecorationType({
-    backgroundColor: new vscode.ThemeColor("diffEditor.insertedTextBackground"),
-  });
-  private readonly deletionDeco = vscode.window.createTextEditorDecorationType({
-    // a non-editable struck-red hint injected AFTER the insertion (INV-52)
-    after: { color: new vscode.ThemeColor("gitDecoration.deletedResourceForeground") },
-    textDecoration: "none",
-  });
+  private readonly insDeco: Record<"human" | "claude", vscode.TextEditorDecorationType> = {
+    human: vscode.window.createTextEditorDecorationType({
+      backgroundColor: "rgba(63,185,80,0.14)", borderColor: "#3fb950",
+      border: "0 0 2px 0", borderStyle: "solid",
+    }),
+    claude: vscode.window.createTextEditorDecorationType({
+      backgroundColor: "rgba(88,166,255,0.15)", borderColor: "#58a6ff",
+      border: "0 0 2px 0", borderStyle: "solid",
+    }),
+  };
+  private readonly delDeco: Record<"human" | "claude" | "none", vscode.TextEditorDecorationType> = {
+    human: vscode.window.createTextEditorDecorationType({ after: { color: "#f85149" } }),
+    claude: vscode.window.createTextEditorDecorationType({ after: { color: "#bc8cff" } }),
+    none: vscode.window.createTextEditorDecorationType({ after: { color: new vscode.ThemeColor("descriptionForeground") } }),
+  };
   private readonly lensEmitter = new vscode.EventEmitter<void>();
   readonly onDidChangeCodeLenses = this.lensEmitter.event;
   /** Pending debounce timers — one per URI — coalesce rapid-fire propose events
@@ -34,13 +44,29 @@ export class EditorProposalController implements vscode.Disposable, vscode.CodeL
    * optimisticApply runs concurrently with the still-in-progress propose loop,
    * causing "file changed in the meantime" workspace-edit conflicts. */
   private readonly pendingApply = new Map<string, ReturnType<typeof setTimeout>>();
+  /** Debounce timers for committed-change re-render (one per URI, 50 ms). */
+  private readonly pendingRender = new Map<string, ReturnType<typeof setTimeout>>();
 
-  constructor(private readonly proposals: ProposalController) {
+  constructor(
+    private readonly proposals: ProposalController,
+    private readonly diffView: DiffViewController,
+    private readonly attribution: AttributionController,
+  ) {
     this.disposables.push(
-      this.insertionDeco, this.deletionDeco, this.lensEmitter,
+      this.insDeco.human, this.insDeco.claude, this.delDeco.human, this.delDeco.claude, this.delDeco.none, this.lensEmitter,
       vscode.languages.registerCodeLensProvider({ language: "markdown" }, this),
       this.proposals.onDidChangeProposals(({ uri }) => this.scheduleApply(uri)),
       vscode.window.onDidChangeActiveTextEditor((ed) => ed && this.renderEditor(ed)),
+      // Refresh committed decorations when the baseline advances (pin / machine-landing / open).
+      this.diffView.onDidChangeBaseline(({ uri }) => {
+        const ed = vscode.window.visibleTextEditors.find((e) => e.document.uri.toString() === uri);
+        if (ed) this.renderEditor(ed);
+      }),
+      // Refresh committed decorations (debounced) when the active doc changes — attribution spans shift.
+      vscode.workspace.onDidChangeTextDocument((e) => {
+        const ed = vscode.window.activeTextEditor;
+        if (ed && e.document === ed.document) this.scheduleRender(ed);
+      }),
       // the four QuickPick-backed menu commands
       vscode.commands.registerCommand("cowriting.proposalAcceptMenu", (id?: string) => this.menu("accept", id)),
       vscode.commands.registerCommand("cowriting.proposalRejectMenu", (id?: string) => this.menu("reject", id)),
@@ -62,6 +88,20 @@ export class EditorProposalController implements vscode.Disposable, vscode.CodeL
     );
   }
 
+  /** Debounce a committed-change re-render for `editor` (50 ms — lets rapid typing settle). */
+  private scheduleRender(editor: vscode.TextEditor): void {
+    const uri = editor.document.uri.toString();
+    const prev = this.pendingRender.get(uri);
+    if (prev !== undefined) clearTimeout(prev);
+    this.pendingRender.set(
+      uri,
+      setTimeout(() => {
+        this.pendingRender.delete(uri);
+        this.renderEditor(editor);
+      }, 50),
+    );
+  }
+
   /** Apply any not-yet-applied proposals on the doc, then re-decorate + refresh lenses. */
   private async onProposalsChanged(uri: string): Promise<void> {
     const doc = vscode.workspace.textDocuments.find((d) => d.uri.toString() === uri);
@@ -80,29 +120,86 @@ export class EditorProposalController implements vscode.Disposable, vscode.CodeL
   /** Decorate the editor for every applied proposal on its document (INV-52). */
   private renderEditor(editor: vscode.TextEditor): void {
     const doc = editor.document;
-    if (doc.languageId !== "markdown") {
-      editor.setDecorations(this.insertionDeco, []);
-      editor.setDecorations(this.deletionDeco, []);
-      return;
-    }
+    const clearAll = () => {
+      for (const a of ["human", "claude"] as const) editor.setDecorations(this.insDeco[a], []);
+      for (const a of ["human", "claude", "none"] as const) editor.setDecorations(this.delDeco[a], []);
+    };
+    if (doc.languageId !== "markdown") return clearAll();
     const key = this.proposals.keyFor(doc);
-    const insertions: vscode.Range[] = [];
-    const deletions: vscode.DecorationOptions[] = [];
+    const ins: Record<"human" | "claude", vscode.Range[]> = { human: [], claude: [] };
+    const del: Record<"human" | "claude" | "none", vscode.DecorationOptions[]> = { human: [], claude: [], none: [] };
+    // Pending proposals — always Claude (INV: proposals are agent-authored).
     for (const v of this.proposals.listProposals(doc)) {
       if (v.anchorStart === null || v.original === undefined || !this.proposals.isApplied(key, v.id)) continue;
       const plan = decorationPlan(v.anchorStart, v.original, v.replacement);
-      for (const ins of plan.insertions) {
-        insertions.push(new vscode.Range(doc.positionAt(ins.start), doc.positionAt(ins.end)));
-      }
-      for (const del of plan.deletions) {
-        deletions.push({
-          range: new vscode.Range(doc.positionAt(del.at), doc.positionAt(del.at)),
-          renderOptions: { after: { contentText: ` ${del.text} `, textDecoration: "line-through" } },
+      for (const i of plan.insertions) ins.claude.push(new vscode.Range(doc.positionAt(i.start), doc.positionAt(i.end)));
+      for (const d of plan.deletions) {
+        del.claude.push({
+          range: new vscode.Range(doc.positionAt(d.at), doc.positionAt(d.at)),
+          renderOptions: { after: { contentText: ` ${d.text} `, textDecoration: "line-through" } },
+        });
+      }
+    }
+    // Committed changes-since-baseline are added by decorateCommitted (pushes into ins/del[author]).
+    this.decorateCommitted(editor, ins, del);
+    for (const a of ["human", "claude"] as const) editor.setDecorations(this.insDeco[a], ins[a]);
+    for (const a of ["human", "claude", "none"] as const) editor.setDecorations(this.delDeco[a], del[a]);
+  }
+
+  /**
+   * Decorates committed (non-proposal) changes-since-baseline by author (Task 7 / reverse INV-32).
+   * Diffs current buffer against the F6 baseline; attributes each changed run to its author;
+   * skips any hunk overlapping an applied pending proposal (the proposal loop owns those).
+   * pin→clean: returns without marking when baseline.reason === "pinned".
+   * Adjacency heuristic: a deletion in a hunk that has insertions inherits the hunk author;
+   * a standalone deletion (hunk with no insertions) renders neutral ("none") — matching the
+   * preview's cw-del-none treatment.
+   */
+  private decorateCommitted(
+    editor: vscode.TextEditor,
+    ins: Record<"human" | "claude", vscode.Range[]>,
+    del: Record<"human" | "claude" | "none", vscode.DecorationOptions[]>,
+  ): void {
+    const doc = editor.document;
+    const baseline = this.diffView.getBaseline(doc.uri.toString());
+    // No baseline yet, or baseline was pinned (pin→clean: no committed marks, INV-48).
+    if (!baseline || baseline.reason === "pinned") return;
+    const current = doc.getText();
+    // Nothing changed — short-circuit before the diff.
+    if (current === baseline.text) return;
+    const spans = this.attribution.spansFor(doc);
+    const key = this.proposals.keyFor(doc);
+    // Build the set of current-buffer ranges owned by applied pending proposals so we
+    // can skip hunks that fall inside them — the proposal loop already decorates those.
+    const appliedRanges: { start: number; end: number }[] = [];
+    for (const v of this.proposals.listProposals(doc)) {
+      if (v.anchorStart !== null && v.original !== undefined && this.proposals.isApplied(key, v.id)) {
+        appliedRanges.push({ start: v.anchorStart, end: v.anchorStart + v.replacement.length });
+      }
+    }
+    // wordEditHunks(current, baseline.text): start/end are in current coords; replacement is baseline text.
+    const hunks = wordEditHunks(current, baseline.text);
+    for (const h of hunks) {
+      // Skip hunks whose current-buffer range overlaps an applied pending proposal.
+      // The skip is whole-hunk and therefore conservative: a committed edit word-merged
+      // into a proposal's hunk is skipped entirely — rare at word granularity.
+      if (appliedRanges.some((r) => h.start < r.end && h.end > r.start)) continue;
+      const author = authorAt(h.start, spans) ?? "human";
+      // h.replacement = baseline text for this span; current.slice(h.start, h.end) = applied text.
+      const plan = decorationPlan(h.start, h.replacement, current.slice(h.start, h.end));
+      for (const i of plan.insertions) {
+        ins[author].push(new vscode.Range(doc.positionAt(i.start), doc.positionAt(i.end)));
+      }
+      // Adjacency heuristic: a deletion paired with an insertion in THIS hunk inherits the
+      // insertion author; a standalone deletion (no insertion in the hunk) is neutral.
+      const delAuthor = plan.insertions.length > 0 ? author : "none";
+      for (const d of plan.deletions) {
+        del[delAuthor].push({
+          range: new vscode.Range(doc.positionAt(d.at), doc.positionAt(d.at)),
+          renderOptions: { after: { contentText: ` ${d.text} `, textDecoration: "line-through" } },
         });
       }
     }
-    editor.setDecorations(this.insertionDeco, insertions);
-    editor.setDecorations(this.deletionDeco, deletions);
   }
 
   /** CodeLensProvider: a `Accept ▾` / `Reject ▾` pair above each applied block. */
@@ -146,6 +243,8 @@ export class EditorProposalController implements vscode.Disposable, vscode.CodeL
   dispose(): void {
     for (const t of this.pendingApply.values()) clearTimeout(t);
     this.pendingApply.clear();
+    for (const t of this.pendingRender.values()) clearTimeout(t);
+    this.pendingRender.clear();
     for (const d of this.disposables) d.dispose();
   }
 }

src/extension.ts

@@ -119,7 +119,7 @@ export function activate(context: vscode.ExtensionContext): CowritingApi | undef
 
   // --- F12 (#64): the editor surface — optimistic-apply proposals into the buffer,
   // decorate the diff, and provide Accept ▾/Reject ▾ CodeLens (INV-48/49/52/53). ---
-  const editorProposalController = new EditorProposalController(proposalController);
+  const editorProposalController = new EditorProposalController(proposalController, diffViewController, attributionController);
   context.subscriptions.push(editorProposalController);
 
   // #46 (INV-42): accept every pending proposal on the active doc in one gesture

src/proposalController.ts

@@ -94,6 +94,7 @@ export class ProposalController implements vscode.Disposable {
         replaced: p.original ?? fp?.text ?? "",
         replacement: p.replacement,
         original: p.original,
+        author: p.author?.kind === "agent" ? "claude" : "human",
       };
     });
   }

src/trackChangesModel.ts

@@ -474,6 +474,76 @@ function wordMergedMarkdown(beforeRaw: string, afterRaw: string): string {
     .join("");
 }
 
+/** The author whose span covers `offset` (half-open [start,end)), or null. */
+export function authorAt(offset: number, spans: AuthorSpan[]): AuthorKind | null {
+  for (const s of spans) if (offset >= s.start && offset < s.end) return s.author;
+  return null;
+}
+
+const insClass = (a: AuthorKind | null): string => `cw-ins-${a ?? "none"}`;
+const delClass = (a: AuthorKind | null): string => `cw-del-${a ?? "none"}`;
+
+/**
+ * Author-colored word diff for a changed PROSE block in the review.
+ * `afterStart` is the landed-text offset of `afterRaw[0]` so an inserted run's
+ * offset maps into `spans`. Insertions are colored by the author covering their
+ * offset; deletions inherit the author of the insertion they are paired with in
+ * the same contiguous change cluster (adjacency heuristic) — `cw-del-none` when a
+ * cluster has no insertion. Pure, deterministic.
+ */
+export function wordDiffByAuthor(
+  beforeRaw: string,
+  afterRaw: string,
+  afterStart: number,
+  spans: AuthorSpan[],
+): string {
+  const parts = diffWordsWithSpace(beforeRaw, afterRaw);
+  // First pass: find each change cluster's insertion author (first added run).
+  // A cluster is a maximal run of added/removed parts bounded by unchanged parts.
+  let afterOff = afterStart;
+  const clusterAuthor: (AuthorKind | null)[] = []; // per part index, the cluster's del author
+  {
+    let off = afterStart;
+    let i = 0;
+    while (i < parts.length) {
+      const p = parts[i];
+      if (!p.added && !p.removed) {
+        clusterAuthor[i] = null;
+        off += p.value.length;
+        i++;
+        continue;
+      }
+      // a cluster: scan to its end, capturing the first added run's author
+      let j = i;
+      let author: AuthorKind | null = null;
+      let scanOff = off;
+      while (j < parts.length && (parts[j].added || parts[j].removed)) {
+        if (parts[j].added && author === null) author = authorAt(scanOff, spans);
+        if (parts[j].added) scanOff += parts[j].value.length;
+        j++;
+      }
+      for (let k = i; k < j; k++) clusterAuthor[k] = author;
+      off = scanOff;
+      i = j;
+    }
+  }
+  // Second pass: emit.
+  const out: string[] = [];
+  parts.forEach((p, i) => {
+    if (p.added) {
+      const a = authorAt(afterOff, spans);
+      out.push(`<ins class="${insClass(a)}">${p.value}</ins>`);
+      afterOff += p.value.length;
+    } else if (p.removed) {
+      out.push(`<del class="${delClass(clusterAuthor[i] ?? null)}">${p.value}</del>`);
+    } else {
+      out.push(p.value);
+      afterOff += p.value.length;
+    }
+  });
+  return out.join("");
+}
+
 export interface RenderOptions {
   /** Per-block markdown→HTML renderer (test seam). Defaults to the bundled markdown-it. */
   render?: (src: string) => string;
@@ -572,15 +642,6 @@ function isCloseSentinel(m: string): boolean {
   return m === SENT.claude.close || m === SENT.human.close;
 }
 
-function authorBadge(authors: Set<AuthorKind>): { cls: string; label: string } | null {
-  if (authors.size === 0) return null;
-  if (authors.size > 1) return { cls: "cw-mixed", label: "mixed" };
-  const only = [...authors][0];
-  return only === "claude"
-    ? { cls: "cw-by-claude", label: "Claude" }
-    : { cls: "cw-by-human", label: "You" };
-}
-
 // Markdown emphasis / code delimiters whose RUNS must never be split by an
 // injected sentinel — a sentinel between two run chars (e.g. `*|*`) breaks
 // markdown-it's delimiter pairing (#33 CASE1).
@@ -601,11 +662,38 @@ function clampOffDelimiterRun(raw: string, at: number): number {
   return p;
 }
 
+/**
+ * Returns the offset within `raw` after block-level markdown markers (ATX
+ * headings, list markers, blockquote markers). Open sentinels must not be
+ * injected before these markers — a PUA char at position 0 would prevent
+ * markdown-it from recognising the block construct (e.g. `##` is only a
+ * heading marker when it is the very first char on the line).
+ */
+function blockContentStart(raw: string): number {
+  // ATX headings: "#{1,6} " at the start of the line.
+  const heading = raw.match(/^#{1,6} /);
+  if (heading) return heading[0].length;
+  // Unordered list markers: "- ", "* ", "+ ".
+  const ul = raw.match(/^[-*+] /);
+  if (ul) return ul[0].length;
+  // Ordered list markers: "N. " or "N) ".
+  const ol = raw.match(/^\d+[.)]\s+/);
+  if (ol) return ol[0].length;
+  // Blockquotes: "> " or ">".
+  const bq = raw.match(/^> ?/);
+  if (bq) return bq[0].length;
+  return 0;
+}
+
 /** Inject paired sentinels into a prose block's raw text for the spans clipped to it. */
 function injectSentinels(raw: string, blockStart: number, spans: AuthorSpan[]): string {
   const inserts: { at: number; marker: string }[] = [];
+  // Open sentinels must not precede block-level markdown markers (heading/list/
+  // blockquote syntax at position 0) — a PUA char before "## " prevents markdown-it
+  // from recognising the heading. Clamp to the content-start offset.
+  const minOpen = blockContentStart(raw);
   for (const s of spans) {
-    const lo = clampOffDelimiterRun(raw, Math.max(0, s.start - blockStart));
+    const lo = Math.max(minOpen, clampOffDelimiterRun(raw, Math.max(0, s.start - blockStart)));
     const hi = clampOffDelimiterRun(raw, Math.min(raw.length, s.end - blockStart));
     if (hi <= lo) continue; // empty (or clamped to empty) span contributes nothing
     inserts.push({ at: lo, marker: SENT[s.author].open });
@@ -632,7 +720,7 @@ const ALL_SENTINELS = new RegExp(
 );
 
 /**
- * #33: token-aware replacement of the rendered author sentinels with `cw-by-*`
+ * #33: token-aware replacement of the rendered author sentinels with `cw-ins-*`
  * spans. A naive global string-replace (the old approach) could emit a span that
  * CROSSES an element boundary — `<span><strong>bo</span>ld</strong>` — when a
  * boundary fell inside an emphasis run (CASE3). This walks the rendered HTML and
@@ -641,13 +729,13 @@ const ALL_SENTINELS = new RegExp(
  * (one `<span>` segment per text run). Tags are copied verbatim (with any stray
  * sentinel stripped, so no Private-Use-Area char ever leaks). Pure, deterministic.
  */
-function sentinelsToSpans(html: string): string {
+function sentinelsToSpans(html: string, kind: "by" | "ins" = "by"): string {
   const out: string[] = [];
   let current: AuthorKind | null = null; // which author region we're inside
   let spanOpen = false; // whether a <span> is currently open in `out`
   const openSpan = () => {
     if (current && !spanOpen) {
-      out.push(`<span class="cw-by-${current}">`);
+      out.push(`<span class="cw-${kind}-${current}">`);
       spanOpen = true;
     }
   };
@@ -695,10 +783,11 @@ export function colorByAuthor(
   blockStart: number,
   spans: AuthorSpan[],
   render: (src: string) => string,
+  kind: "by" | "ins" = "by",
 ): string {
   const overlapping = spans.filter((s) => s.end > blockStart && s.start < blockStart + raw.length);
   const injected = injectSentinels(raw, blockStart, overlapping);
-  return sentinelsToSpans(render(injected));
+  return sentinelsToSpans(render(injected), kind);
 }
 
 /**
@@ -739,6 +828,8 @@ export interface ProposalView {
   replacement: string;
   /** F12/#64 (INV-48): the pre-apply original, set after optimistic apply. */
   original?: string;
+  /** Who made the proposal — colors the del/ins. Defaults to "claude". */
+  author?: AuthorKind;
 }
 
 function proposalBlockHtml(p: ProposalView, render: (src: string) => string): string {
@@ -750,8 +841,9 @@ function proposalBlockHtml(p: ProposalView, render: (src: string) => string): st
     }
   };
   const unanchored = p.anchorStart === null ? " cw-proposal-unanchored" : "";
-  const before = p.replaced ? `<del class="cw-del">${safe(p.replaced)}</del>` : "";
-  const after = `<ins class="cw-add">${safe(p.replacement)}</ins>`;
+  const who = p.author ?? "claude";
+  const before = p.replaced ? `<del class="cw-del-${who}">${safe(p.replaced)}</del>` : "";
+  const after = `<ins class="cw-ins-${who}">${safe(p.replacement)}</ins>`;
   const actions =
     `<span class="cw-actions">` +
     `<span class="cw-btngroup">` +
@@ -769,20 +861,27 @@ function proposalBlockHtml(p: ProposalView, render: (src: string) => string): st
 function renderReviewOp(
   op: BlockOp,
   render: (src: string) => string,
-  colored: (raw: string) => string,
   src: string,
+  changedHtml?: string,
 ): string {
-  // removed blocks and any changed block (atomic fences diffed whole; non-atomic prose
-  // word-merged) render via renderOp — no author sentinels (deletions neutral, spec §6.7).
-  // `src` is "" for a removed block (no live source — INV-36).
+  // A non-atomic changed prose block is pre-rendered with author-colored ins/del
+  // (changedHtml). Removed blocks and atomic changed fences stay neutral via renderOp
+  // (standalone deletion → neutral, per the adjacency heuristic). `src` is "" for a
+  // removed block (no live source — INV-36).
+  if (op.kind === "changed" && !op.atomic && changedHtml !== undefined) {
+    return `<div class="cw-blk cw-changed"${src}>${changedHtml}</div>`;
+  }
   if (op.kind === "removed" || op.kind === "changed") return renderOp(op, render, src);
-  return `<div class="cw-blk ${op.kind === "added" ? "cw-added" : "cw-unchanged"}"${src}>${colored(op.block.raw)}</div>`;
+  // "added": changedHtml is colorByAuthor sentinel output (markdown-safe, cw-ins-*).
+  // "unchanged": render(raw) — plain, no author coloring (color = "changed since baseline").
+  return `<div class="cw-blk ${op.kind === "added" ? "cw-added" : "cw-unchanged"}"${src}>${changedHtml ?? render(op.block.raw)}</div>`;
 }
 
 /**
- * On-state body (INV-33): the F7 baseline diff — added/changed PROSE author-colored
- * via colorByAuthor (F9 sentinels), deletions struck — overlaid with F4 pending
- * proposals as blue cw-proposal blocks (✓/✗). One pass, pure, vscode-free.
+ * On-state body: the F7 baseline diff — added/changed PROSE author-colored via
+ * wordDiffByAuthor (cw-ins-{author}/cw-del-{author} per token), unchanged blocks render plain,
+ * deletions struck neutral — overlaid with F4 pending proposals as blue cw-proposal
+ * blocks (✓/✗). One pass, pure, vscode-free.
  *
  * A resolved proposal renders INLINE, right after the current-side block its anchor
  * falls in (#31) — so "what is Claude proposing, and where?" is answered by
@@ -833,11 +932,9 @@ export function renderReview(
   const ops = diffBlocks(baselineText, landedText);
   // #48: right after a PIN (baseline reason "pinned") with no changes since, the
   // panel is fully clean: no change marks (already absent) AND no authorship
-  // coloring, so the pin reads as "this is my clean starting point". Skip
-  // colorByAuthor for every block in this case; data-src mapping and any pending
-  // proposals (review actions, not annotations) are kept below. A baseline advanced
-  // by a machine-landing (accept) is ALSO zero-diff but is NOT pinned — it keeps
-  // its authorship coloring (F10 INV-33), so this is gated on the pin specifically.
+  // coloring, so the pin reads as "this is my clean starting point". Suppress
+  // wordDiffByAuthor for every block in this case; data-src mapping and any pending
+  // proposals (review actions, not annotations) are kept below.
   const clean = opts.pinned === true && ops.every((o) => o.kind === "unchanged");
 
   // Map a currentText offset to its landedText offset (account for reverted spans
@@ -889,9 +986,22 @@ export function renderReview(
   for (const op of ops) {
     const blockIndex = op.kind === "removed" ? -1 : ci;
     const blk = op.kind === "removed" ? undefined : ranges[ci++];
-    const colored = (raw: string): string =>
-      blk && !clean ? colorByAuthor(raw, blk.start, landedSpans, render) : render(raw);
-    bodyParts.push(renderReviewOp(op, render, colored, srcAttr(blk)));
+    // Only ADDED and CHANGED prose blocks are author-colored (they differ since baseline);
+    // UNCHANGED blocks render plain (color means "changed since baseline").
+    // A non-atomic changed prose block: author-colored word diff (ins by author,
+    // del by adjacency). An added block: sentinel-safe colorByAuthor with kind="ins"
+    // (markdown-it parses the block first, so ## → <h2> before sentinels become spans;
+    // the old wordDiffByAuthor path wrapped raw in <ins> BEFORE parsing — structural bug).
+    // `blk.start` is the landed offset of the after-side text.
+    const changedHtml =
+      blk && !clean
+        ? op.kind === "changed" && !op.atomic
+          ? render(wordDiffByAuthor(op.before.raw, op.block.raw, blk.start, landedSpans))
+          : op.kind === "added"
+          ? colorByAuthor(op.block.raw, blk.start, landedSpans, render, "ins")
+          : undefined
+        : undefined;
+    bodyParts.push(renderReviewOp(op, render, srcAttr(blk), changedHtml));
     const here = blockIndex >= 0 ? byBlock.get(blockIndex) : undefined;
     if (here) for (const p of here) bodyParts.push(proposalBlockHtml(p, render));
   }

test/e2e/suite/authorship.test.ts

@@ -16,15 +16,16 @@ async function getApi(): Promise<CowritingApi> {
 
 // F10 host E2E (no LLM): the rewrite of the obsolete F9 authorship-mode test.
 // F9's "authorship" mode / renderAuthorship is gone — the on-state renderReview
-// now author-colors Claude's landed prose. This suite confirms a Claude-landed
-// span renders as a cw-by-claude span in the on-state preview HTML. Owns its own
-// markdown doc, disjoint from the other suites' fixtures.
-suite("F10 review preview — Claude-authored prose is cw-by-claude in the on-state (host E2E, no LLM)", () => {
+// now author-colors Claude's PENDING proposal blocks as cw-ins-claude. After the
+// proposal is accepted the baseline advances (INV-18/F12) and the text becomes
+// "unchanged" → renders plain. The class to check is cw-ins-claude (proposal block),
+// NOT cw-by-claude (the old F9 authorship render). Owns its own markdown doc.
+suite("F10 review preview — pending Claude proposal renders cw-ins-claude in the on-state (host E2E, no LLM)", () => {
   const DOC_REL = "docs/f10claude.md";
   const TARGET = "The sentence Claude will compose over.";
   const REPLACEMENT = "The sentence CLAUDE COMPOSED via the seam.";
 
-  test("an accepted Claude edit author-colors as cw-by-claude in the on-state render; mode defaults to on", async () => {
+  test("a pending Claude proposal carries cw-ins-claude; accepted proposal leaves attribution data intact; mode defaults to on", async () => {
     const abs = path.join(WS, DOC_REL);
     fs.mkdirSync(path.dirname(abs), { recursive: true });
     fs.writeFileSync(abs, `# F10\n\n${TARGET}\n`, "utf8");
@@ -41,7 +42,7 @@ suite("F10 review preview — Claude-authored prose is cw-by-claude in the on-st
     assert.ok(api.trackChangesPreviewController.isOpen(key), "preview open");
     assert.strictEqual(api.trackChangesPreviewController.getMode(key), "on", "annotations default to on");
 
-    // Claude composes via the seam (propose → accept)
+    // Claude proposes via the seam (F12 optimistic-apply; proposal stays PENDING)
     const start = doc.getText().indexOf(TARGET);
     const id = await vscode.commands.executeCommand<string>("cowriting.proposeAgentEdit", {
       uri: key,
@@ -52,17 +53,26 @@ suite("F10 review preview — Claude-authored prose is cw-by-claude in the on-st
       sessionId: "e2e-f10",
       turnId: "turn-f10",
     });
+    assert.ok(id, "propose returns an id");
+    await settle();
+
+    // PENDING proposal: the preview renders the proposal block with cw-ins-claude.
+    // After accepting, the baseline advances (INV-18) → the text becomes "unchanged"
+    // and renders plain — so we check BEFORE accepting.
+    const pendingHtml = api.trackChangesPreviewController.renderHtmlFor(key);
+    assert.ok(
+      pendingHtml.includes("cw-ins-claude"),
+      "pending Claude proposal block carries cw-ins-claude in the on-state render",
+    );
+
+    // accept via the seam — baseline advances (machine-landing, INV-18/F12)
     assert.ok(await api.proposalController.acceptById(DOC_REL, id!), "accept applies via the seam");
     await settle();
 
     // attribution recorded a Claude (agent) span (data layer intact)
     const claudeSpan = api.attributionController.getSpans(DOC_REL).find((s) => s.authorKind === "agent");
-    assert.ok(claudeSpan, "Claude span recorded by F3");
+    assert.ok(claudeSpan, "Claude span recorded by F3 (data layer intact after accept)");
     const spans = api.attributionController.spansFor(doc);
     assert.ok(spans.some((s) => s.author === "claude"), "spansFor reports a Claude span for the preview");
-
-    // the on-state render author-colors the landed Claude text as cw-by-claude
-    const html = api.trackChangesPreviewController.renderHtmlFor(key);
-    assert.match(html, /<span class="cw-by-claude">/, "landed Claude prose is author-colored in the on-state render");
   });
 });

test/e2e/suite/f10Review.test.ts

@@ -74,7 +74,7 @@ suite("F10 interactive review (host E2E — preview is the single review surface
     void doc;
   });
 
-  test("typing produces an added/changed block and a cw-by-human span in the on-state render (PUC-2)", async () => {
+  test("typing produces an added/changed block and a cw-ins-human span in the on-state render (PUC-2)", async () => {
     const { key } = await reopen(DOC_REL);
     const api = await getApi();
     const doc = byKey(key)!;
@@ -85,13 +85,13 @@ suite("F10 interactive review (host E2E — preview is the single review surface
     const kinds = (api.trackChangesPreviewController.getLastModel(key) ?? []).map((o) => o.kind);
     assert.ok(kinds.some((k) => k === "added" || k === "changed"), "an added/changed block after typing");
     // Attribution recorded the human span (data layer), and the on-state render
-    // author-colors that prose as cw-by-human.
+    // author-colors that prose as cw-ins-human (added blocks use cw-ins-{author} since Task 3/44ef0a2).
     assert.ok(
       api.attributionController.spansFor(doc).some((s) => s.author === "human"),
       "a human span was recorded for the typed text",
     );
     const html = api.trackChangesPreviewController.renderHtmlFor(key);
-    assert.match(html, /<span class="cw-by-human">/, "typed text is author-colored human in the on-state");
+    assert.ok(html.includes("cw-ins-human"), "typed text is author-colored human in the on-state (cw-ins-human for added blocks)");
   });
 
   test("propose → the preview surfaces it as a cw-proposal block with ✓/✗ actions (PUC-3)", async () => {
@@ -175,7 +175,7 @@ suite("F10 interactive review (host E2E — preview is the single review surface
     // (INV-33). Assert the actual off-state body the controller posts has no cw-
     // author/proposal marks — meaningful because the on-state above DID carry one.
     const offBody = renderPlain(doc.getText());
-    assert.ok(!/cw-proposal|cw-by-claude|cw-by-human|cw-del/.test(offBody), "off-state render carries no cw- marks");
+    assert.ok(!/cw-proposal|cw-by-|cw-ins-|cw-del/.test(offBody), "off-state render carries no cw- marks");
 
     // toggle back on → marks return.
     api.trackChangesPreviewController.setMode(key, "on");
@@ -232,6 +232,60 @@ suite("F10 interactive review (host E2E — preview is the single review surface
     assert.ok(all.includes("cowriting.pinDiffBaseline"), "pinDiffBaseline (baseline data layer) is kept");
     void key;
   });
+
+  test("author-colored track changes: cw-ins-human + cw-ins-claude appear; unchanged blocks are plain (Tasks 1-4)", async () => {
+    // Fresh doc with three blocks: one that stays unchanged, one for Claude to target, one for human typing.
+    const { doc, key } = await freshDoc(
+      "docs/f10authorcolors.md",
+      "# Author Colors\n\nUnchanged paragraph that stays.\n\nClaude target block.\n",
+    );
+    const api = await getApi();
+    await vscode.commands.executeCommand("cowriting.showTrackChangesPreview");
+    await settle();
+
+    // Human types a new paragraph → an "added" block relative to the opened baseline.
+    const edit = new vscode.WorkspaceEdit();
+    edit.insert(doc.uri, doc.positionAt(doc.getText().length), "\n\nHuman typed paragraph.\n");
+    assert.ok(await vscode.workspace.applyEdit(edit), "human edit applied");
+    await settle();
+
+    // Propose a Claude change (stays PENDING — F12 optimistic-apply; NOT accepted).
+    // The proposal block renders with cw-ins-claude.
+    const target = "Claude target block.";
+    const targetStart = doc.getText().indexOf(target);
+    assert.ok(targetStart >= 0, "target text present after human edit");
+    await vscode.commands.executeCommand<string>("cowriting.proposeAgentEdit", {
+      uri: key,
+      start: targetStart,
+      end: targetStart + target.length,
+      newText: "Claude replacement block.",
+      model: "sonnet",
+      sessionId: "e2e-f10-colors",
+      turnId: "turn-colors-1",
+    });
+    await settle();
+
+    const html = api.trackChangesPreviewController.renderHtmlFor(key);
+
+    // The human-typed added block renders with cw-ins-human.
+    assert.ok(html.includes("cw-ins-human"), "human added block is colored cw-ins-human");
+
+    // The pending Claude proposal block renders with cw-ins-claude.
+    assert.ok(html.includes("cw-ins-claude"), "pending Claude proposal block carries cw-ins-claude");
+
+    // The unchanged block renders as cw-unchanged with no cw-ins-/cw-by- inside it
+    // (color = "changed since baseline"; unchanged text is never annotated).
+    const unchangedBlocks = [...html.matchAll(/<div class="cw-blk cw-unchanged"[^>]*>([\s\S]*?)<\/div>/g)];
+    assert.ok(unchangedBlocks.length > 0, "at least one unchanged block exists");
+    assert.ok(
+      unchangedBlocks.some((m) => m[1].includes("Unchanged paragraph that stays")),
+      "the unchanged paragraph is in a cw-unchanged block",
+    );
+    assert.ok(
+      unchangedBlocks.every((m) => !/cw-ins-|cw-by-/.test(m[1])),
+      "unchanged blocks carry no cw-ins- or cw-by- classes",
+    );
+  });
 });
 
 // ---- helpers reused across the order-dependent main-flow tests ----

test/e2e/suite/s48PinClean.test.ts

@@ -41,15 +41,15 @@ suite("S48 — pin → fully clean review panel (host E2E, no LLM)", () => {
     edit.insert(doc.uri, doc.positionAt(doc.getText().length), "\n\nA freshly typed human paragraph.\n");
     assert.ok(await vscode.workspace.applyEdit(edit), "operator edit applied");
     await settle();
-    assert.match(ctl.renderHtmlFor(key), /cw-by-human/, "typed text is author-colored before the pin");
+    assert.match(ctl.renderHtmlFor(key), /cw-ins-human/, "typed text is author-colored cw-ins-human before the pin");
 
     // Pin the baseline → zero diff → the panel must be fully clean.
     ctl.receiveMessage(key, { type: "pinBaseline" });
     await settle();
     const pinned = ctl.renderHtmlFor(key);
-    assert.ok(!pinned.includes("cw-by-human"), "no human authorship coloring after pin");
-    assert.ok(!pinned.includes("cw-by-claude"), "no Claude authorship coloring after pin");
-    assert.ok(!pinned.includes("cw-add") && !pinned.includes("cw-del"), "no change marks after pin");
+    assert.ok(!pinned.includes("cw-ins-human"), "no human insertion marks after pin");
+    assert.ok(!pinned.includes("cw-ins-claude"), "no Claude insertion marks after pin");
+    assert.ok(!pinned.includes("cw-ins-") && !pinned.includes("cw-del-"), "no insertion or deletion marks after pin");
     assert.match(pinned, /data-src-start/, "blocks still carry data-src offsets (INV-36 mapping kept)");
     assert.ok(pinned.includes("freshly typed human paragraph"), "the body text is still rendered, just plain");
 
@@ -58,6 +58,6 @@ suite("S48 — pin → fully clean review panel (host E2E, no LLM)", () => {
     edit2.insert(doc.uri, doc.positionAt(doc.getText().length), "\n\nA second typed paragraph diverges again.\n");
     assert.ok(await vscode.workspace.applyEdit(edit2), "second operator edit applied");
     await settle();
-    assert.match(ctl.renderHtmlFor(key), /cw-by-human/, "authorship coloring returns once the doc diverges from the pin");
+    assert.match(ctl.renderHtmlFor(key), /cw-ins-human/, "cw-ins-human authorship coloring returns once the doc diverges from the pin");
   });
 });

test/e2e/suite/undoMarks.test.ts

@@ -78,8 +78,9 @@ suite("F10 #38 — undo does not mis-attribute restored text (host E2E, no LLM)"
     );
 
     // And the on-state render must not color 'bravo' as human-authored.
+    // Added blocks use cw-ins-human (not cw-by-human) since Task 3/44ef0a2.
     const html = api.trackChangesPreviewController.renderHtmlFor(key);
-    const bravoColoredHuman = /<span class="cw-by-human">[^<]*bravo/.test(html);
-    assert.ok(!bravoColoredHuman, "restored 'bravo' is not colored cw-by-human in the preview");
+    const bravoColoredHuman = /cw-ins-human[^<]*bravo|<[^>]+class="[^"]*cw-ins-human[^"]*"[^>]*>[^<]*bravo/.test(html);
+    assert.ok(!bravoColoredHuman, "restored 'bravo' is not colored cw-ins-human in the preview");
   });
 });

test/trackChangesModel.test.ts

@@ -1,5 +1,7 @@
 import { describe, it, test, expect } from "vitest";
-import { splitBlocks, splitBlocksWithRanges, diffBlocks, diffToHunks, diffToBlockHunks, renderTrackChanges, colorByAuthor, type AuthorSpan } from "../src/trackChangesModel";
+import MarkdownIt from "markdown-it";
+import { splitBlocks, splitBlocksWithRanges, diffBlocks, diffToHunks, diffToBlockHunks, renderTrackChanges, colorByAuthor, authorAt, wordDiffByAuthor, type AuthorSpan } from "../src/trackChangesModel";
+const md = new MarkdownIt({ html: true, linkify: false, breaks: false });
 
 describe("splitBlocks", () => {
   it("splits prose paragraphs on blank lines, dropping empties", () => {
@@ -170,12 +172,11 @@ describe("colorByAuthor", () => {
   });
 
   // #33: author-coloring must be sentinel-safe around markdown emphasis. These
-  // exercise the REAL markdown-it renderer (via renderReview on an unchanged doc),
-  // since the failure is in markdown-it's inline parsing / element nesting.
+  // exercise colorByAuthor directly with the real markdown-it renderer (unchanged
+  // blocks now render plain in renderReview, so sentinel testing requires a direct call).
   // CASE1 — a span boundary strictly inside a delimiter run must not split it.
   test("#33 CASE1: a span boundary inside ** does not break emphasis parsing", () => {
-    const doc = "a**b**c";
-    const html = renderReview(doc, doc, [{ start: 0, end: 2, author: "human" }], []);
+    const html = colorByAuthor("a**b**c", 0, [{ start: 0, end: 2, author: "human" }], src => md.render(src));
     expect(html).toContain("<strong>b</strong>"); // emphasis still renders
     expect(html).not.toContain("**"); // no raw delimiters left
     expect(html).not.toContain("<em></em>"); // no stray empty emphasis (the parse-break symptom)
@@ -184,16 +185,14 @@ describe("colorByAuthor", () => {
   // CASE3 — a span boundary inside an emphasis run must color the text without
   // misnesting span/element (the span is split at the element boundary).
   test("#33 CASE3: a span boundary inside **bold** colors the text without misnesting", () => {
-    const doc = "**bold**";
-    const html = renderReview(doc, doc, [{ start: 0, end: 4, author: "human" }], []); // covers "**bo"
+    const html = colorByAuthor("**bold**", 0, [{ start: 0, end: 4, author: "human" }], src => md.render(src)); // covers "**bo"
     expect(html).toContain("<strong>");
     expect(html).toContain('<span class="cw-by-human">bo</span>ld</strong>'); // span INSIDE strong, closed before "ld"
     expect(html).not.toContain('cw-by-human"><strong>'); // NOT the old misnest (span wrapping the <strong> open)
   });
   // CASE2 — a span covering a whole emphasis run stays correct (regression).
   test("#33 CASE2: a span over the whole **bold** colors it correctly", () => {
-    const doc = "**bold**";
-    const html = renderReview(doc, doc, [{ start: 0, end: 8, author: "human" }], []);
+    const html = colorByAuthor("**bold**", 0, [{ start: 0, end: 8, author: "human" }], src => md.render(src));
     expect(html).toContain("<strong>");
     expect((html.match(/cw-by-human/g) ?? []).length).toBe(1);
     expect(html).toContain("bold");
@@ -209,7 +208,98 @@ describe("colorByAuthor", () => {
   });
 });
 
-import { renderPlain } from "../src/trackChangesModel";
+describe("authorAt", () => {
+  const spans: AuthorSpan[] = [
+    { start: 0, end: 5, author: "human" },
+    { start: 5, end: 10, author: "claude" },
+  ];
+  test("returns the covering span's author (half-open)", () => {
+    expect(authorAt(0, spans)).toBe("human");
+    expect(authorAt(4, spans)).toBe("human");
+    expect(authorAt(5, spans)).toBe("claude");
+    expect(authorAt(9, spans)).toBe("claude");
+  });
+  test("returns null outside any span", () => {
+    expect(authorAt(10, spans)).toBeNull();
+    expect(authorAt(-1, spans)).toBeNull();
+  });
+});
+
+describe("wordDiffByAuthor", () => {
+  test("an inserted run is colored by the author covering its landed offset", () => {
+    // before "hello " ; after "hello brave " ; "brave " inserted at landed offset 6..12
+    const spans: AuthorSpan[] = [{ start: 6, end: 12, author: "claude" }];
+    const html = wordDiffByAuthor("hello ", "hello brave ", 0, spans);
+    expect(html).toContain('<ins class="cw-ins-claude">brave </ins>');
+    expect(html).toContain("hello ");
+  });
+  test("a paired deletion inherits the paired insertion's author (adjacency)", () => {
+    // "light" -> "dark", both in one cluster; "dark" is claude-inserted
+    const spans: AuthorSpan[] = [{ start: 0, end: 4, author: "claude" }];
+    const html = wordDiffByAuthor("light", "dark", 0, spans);
+    expect(html).toContain('<del class="cw-del-claude">light</del>');
+    expect(html).toContain('<ins class="cw-ins-claude">dark</ins>');
+  });
+  test("a standalone deletion (no paired insertion) is neutral", () => {
+    const html = wordDiffByAuthor("keep this word", "keep word", 0, []);
+    expect(html).toContain('<del class="cw-del-none">this </del>');
+    expect(html).not.toContain("cw-del-human");
+    expect(html).not.toContain("cw-del-claude");
+  });
+  test("emits SIBLING ins/del elements, never nested — CSS overlap rule in preview.css is a defensive forward guarantee", () => {
+    // The engine assigns the cluster's insertion author to all deletions in the same
+    // cluster (adjacency heuristic), so <del> and <ins> always carry the SAME author
+    // as siblings. Cross-author nesting (<del class="cw-del-X"><ins class="cw-ins-Y">)
+    // is never produced today. The CSS rule `.cw-del-claude .cw-ins-human { text-decoration: inherit }`
+    // guards against a future regression where such nesting appears.
+    const spans: AuthorSpan[] = [{ start: 0, end: 100, author: "human" }];
+    const html = wordDiffByAuthor("old text", "new text", 0, spans);
+    expect(html).toContain('<del class="cw-del-human">');
+    expect(html).toContain('<ins class="cw-ins-human">');
+    // Structural check: no <del> immediately wraps an <ins> (sibling, not nested).
+    // /<del[^>]*>[^<]*<ins/ would match a nested case but not a sibling case
+    // because [^<]* stops before the closing </del> tag.
+    expect(html).not.toMatch(/<del[^>]*>[^<]*<ins/);
+  });
+});
+
+import { renderPlain, wordEditHunks, decorationPlan } from "../src/trackChangesModel";
+
+test("committed change: wordEditHunks(current, baseline) → start/end index current; replacement is baseline text", () => {
+  const baseline = "the light mode";
+  const current = "the dark mode";
+  const [h] = wordEditHunks(current, baseline);
+  expect(current.slice(h.start, h.end)).toContain("dark");   // applied (current) side
+  expect(h.replacement).toContain("light");                  // baseline (deleted) side
+  const plan = decorationPlan(h.start, h.replacement, current.slice(h.start, h.end));
+  expect(plan.insertions.length).toBeGreaterThan(0);
+  expect(plan.deletions.some((d) => d.text.includes("light"))).toBe(true);
+});
+
+test("committed change with NO shared prefix: current offsets + deleted text both correct", () => {
+  const baseline = "alpha tail";
+  const current = "beta tail";
+  const [h] = wordEditHunks(current, baseline);
+  expect(h.start).toBe(0);
+  expect(current.slice(h.start, h.end)).toContain("beta");   // applied
+  const plan = decorationPlan(h.start, h.replacement, current.slice(h.start, h.end));
+  expect(plan.deletions.some((d) => d.text.includes("alpha"))).toBe(true); // deletion not lost
+});
+
+test("standalone committed deletion → plan has no insertions (controller routes del to neutral)", () => {
+  // current = "keep word" (baseline had "this " between "keep " and "word" — standalone deletion)
+  const [h] = wordEditHunks("keep word", "keep this word");
+  const plan = decorationPlan(h.start, h.replacement, "keep word".slice(h.start, h.end));
+  expect(plan.insertions.length).toBe(0);
+  expect(plan.deletions.some((d) => d.text.includes("this"))).toBe(true);
+});
+
+test("paired committed replace → plan has insertions (deletion inherits author, not neutral)", () => {
+  // current = "the dark mode", baseline = "the light mode" — replacement, so paired
+  const [h] = wordEditHunks("the dark mode", "the light mode");
+  const plan = decorationPlan(h.start, h.replacement, "the dark mode".slice(h.start, h.end));
+  expect(plan.insertions.length).toBeGreaterThan(0);
+});
 
 describe("renderPlain", () => {
   test("renderPlain renders current buffer as plain markdown (no marks)", () => {
@@ -223,13 +313,15 @@ describe("renderPlain", () => {
 import { renderReview, type ProposalView } from "../src/trackChangesModel";
 
 describe("renderReview", () => {
-  test("renderReview: human addition since baseline renders green ins / cw-by-human", () => {
-    const html = renderReview("hello", "hello world", [{ start: 6, end: 11, author: "human" }], []);
-    expect(html).toMatch(/<ins>[^<]*world[^<]*<\/ins>|cw-by-human/);
+  test("renderReview: human addition since baseline renders author-colored ins", () => {
+    // " world" is one diff token starting at offset 5 (the space), so the author span
+    // must start at 5 or earlier to cover the token's start offset.
+    const html = renderReview("hello", "hello world", [{ start: 5, end: 11, author: "human" }], []);
+    expect(html).toContain("cw-ins-human");
   });
-  test("renderReview: deletion since baseline renders struck del/cw-del", () => {
+  test("renderReview: a standalone deletion since baseline renders neutral struck del", () => {
     const html = renderReview("hello world", "hello", [], []);
-    expect(html).toMatch(/<del>|cw-del/);
+    expect(html).toMatch(/cw-del-none|cw-removed/);
   });
   test("renderReview: a pending proposal renders a blue block with data-proposal-id and Accept/Reject actions", () => {
     const proposals: ProposalView[] = [{ id: "p1", anchorStart: 0, anchorEnd: 5, replaced: "hello", replacement: "goodbye" }];
@@ -261,13 +353,15 @@ describe("renderReview", () => {
   test("renderReview: author-colors the correct block when two paragraphs are identical", () => {
     // Two identical paragraphs; baseline has only the first, so the SECOND is an
     // added block authored by human. Its span must color THAT block, not the first.
+    // (Unchanged first block renders plain; added second block uses wordDiffByAuthor.)
     const baseline = "Hello world";
     const current = "Hello world\n\nHello world";
-    // second "Hello world" starts at offset 13; "world" at 19..24
-    const spans = [{ start: 19, end: 24, author: "human" as const }];
+    // second "Hello world" starts at offset 13 (past the "\n\n"); span covers the block.
+    // wordDiffByAuthor emits the whole block as one added token at offset 13.
+    const spans = [{ start: 13, end: 24, author: "human" as const }];
     const html = renderReview(baseline, current, spans, []);
-    // exactly one cw-by-human span (the added second block's "world"), not zero, not on the first.
-    const count = (html.match(/cw-by-human/g) ?? []).length;
+    // exactly one cw-ins-human (the added second block), not zero, not on the first.
+    const count = (html.match(/cw-ins-human/g) ?? []).length;
     expect(count).toBe(1);
   });
 
@@ -346,22 +440,24 @@ describe("renderReview", () => {
     expect(html).toContain('data-proposal-id="p1"'); // proposal still shows (it is an action)
     expect(html).toContain("Person");
   });
-  test("renderReview: zero diff WITHOUT a pin (e.g. machine-landing) keeps authorship coloring (INV-33)", () => {
-    // accepting a Claude edit advances the baseline (zero diff) but is NOT a pin —
-    // the landed author coloring must remain.
+  test("renderReview: zero diff (e.g. machine-landing accept) renders unchanged blocks plain (Task 2 behavior)", () => {
+    // Task 2: unchanged blocks always render plain — color means "changed since baseline".
+    // After accepting a Claude edit the text is the new baseline; no diff → no coloring.
     const doc = "Human wrote this.\n\nClaude wrote that.";
     const spans: AuthorSpan[] = [{ start: 19, end: doc.length, author: "claude" }];
     const html = renderReview(doc, doc, spans, []); // no pinned flag
-    expect(html).toContain("cw-by-claude");
+    expect(html).not.toContain("cw-by-claude");
+    expect(html).toContain("Claude wrote that."); // text still present
   });
-  test("renderReview: with REAL changes since a pin, author coloring returns", () => {
+  test("renderReview: with REAL changes since a pin, author coloring returns on added blocks", () => {
     // a genuine added block is still author-colored even when pinned (only the
-    // zero-diff-after-pin state is clean).
+    // zero-diff-after-pin state is clean). Task 2: coloring is via cw-ins-*.
     const baseline = "Hello world";
     const current = "Hello world\n\nHello world";
-    const spans: AuthorSpan[] = [{ start: 19, end: 24, author: "human" }];
+    // span covers the added block from its start (offset 13) so the whole token is colored.
+    const spans: AuthorSpan[] = [{ start: 13, end: 24, author: "human" }];
     const html = renderReview(baseline, current, spans, [], { pinned: true });
-    expect((html.match(/cw-by-human/g) ?? []).length).toBe(1);
+    expect((html.match(/cw-ins-human/g) ?? []).length).toBe(1);
   });
 
   test("renderReview is deterministic with mixed anchored/unanchored proposals", () => {
@@ -393,24 +489,26 @@ describe("renderReview", () => {
     expect(html).not.toContain("<del>brown</del>"); // no double-render of the change as a baseline diff
   });
 
-  test("renderReview keeps author coloring aligned on a block AFTER a length-changing pending proposal (INV-49/50)", () => {
-    // block 1 has a pending proposal whose applied text is MUCH LONGER than its
-    // original; block 2 carries a Claude authorship span (in currentText coords).
-    const baseline = "one short.\n\ntwo stable here.\n";
-    const current = "one MUCH LONGER REPLACED TEXT.\n\ntwo stable here.\n";
+  test("renderReview keeps author coloring aligned on an ADDED block AFTER a length-changing pending proposal (INV-49/50)", () => {
+    // block 1 has a pending proposal (MUCH LONGER than original); block 2 is a NEW
+    // paragraph with a Claude authorship span (in currentText coords). The toLanded
+    // mapping must shift the span's coords so the added block is correctly colored.
+    const baseline = "old.";
+    const current = "LONGER REPLACEMENT.\n\nAdded para.";
     const proposals: ProposalView[] = [{
       id: "pr_1",
-      anchorStart: current.indexOf("one MUCH LONGER REPLACED TEXT."),
-      anchorEnd: current.indexOf("one MUCH LONGER REPLACED TEXT.") + "one MUCH LONGER REPLACED TEXT.".length,
-      replaced: "one short.",
-      replacement: "one MUCH LONGER REPLACED TEXT.",
-      original: "one short.",
+      anchorStart: 0,
+      anchorEnd: "LONGER REPLACEMENT.".length,
+      replaced: "old.",
+      replacement: "LONGER REPLACEMENT.",
+      original: "old.",
     }];
-    const sStart = current.indexOf("stable");
-    const authorSpans = [{ start: sStart, end: sStart + "stable".length, author: "claude" as const }];
+    // "Added" in currentText starts at: "LONGER REPLACEMENT.\n\n".length = 21
+    const aStart = current.indexOf("Added");
+    const authorSpans = [{ start: aStart, end: aStart + "Added".length, author: "claude" as const }];
     const html = renderReview(baseline, current, authorSpans, proposals);
-    // the Claude coloring wraps "stable" exactly — not shifted by the proposal's length delta.
-    expect(html).toMatch(/<span class="cw-by-claude">stable<\/span>/);
+    // "Added" in the landedText block should be claude-colored despite the coordinate shift.
+    expect(html).toContain("cw-ins-claude");
   });
 
   test("proposalBlockHtml renders Accept/Reject controls with dropdown carets (#64)", () => {
@@ -424,6 +522,45 @@ describe("renderReview", () => {
     expect(html).toMatch(/Accept/);
     expect(html).toMatch(/Reject/);
   });
+
+  test("renderReview: a changed prose block colors ins/del by author (claude replace)", () => {
+    // baseline "light" -> current "dark"; "dark" attributed to claude at 0..4
+    const html = renderReview("light", "dark", [{ start: 0, end: 4, author: "claude" }], []);
+    expect(html).toContain('cw-ins-claude');
+    expect(html).toContain('cw-del-claude'); // adjacency: struck "light" inherits claude
+  });
+
+  test("renderReview: an unchanged block renders plain (no author coloring)", () => {
+    const doc = "Alpha stays.";
+    const html = renderReview(doc, doc, [{ start: 0, end: 12, author: "human" }], []);
+    expect(html).not.toContain("cw-by-");
+    expect(html).not.toContain("cw-ins-");
+  });
+
+  test("renderReview: an added block is author-colored as an insertion", () => {
+    // baseline empty-ish -> add a new paragraph authored by human
+    const html = renderReview("Keep.", "Keep.\n\nFresh line.", [{ start: 6, end: 17, author: "human" }], []);
+    expect(html).toContain("cw-ins-human");
+  });
+
+  test("renderReview: an added heading block renders as a heading AND is author-colored as an insertion", () => {
+    // "Intro.\n\n" = 8 chars; "## New Section" = 14 chars → offset 8..22 in currentText.
+    // Before fix: wordDiffByAuthor wrapped raw in <ins> BEFORE markdown-it parsed it,
+    // so "## New Section" rendered as literal text (structural bug). After fix:
+    // colorByAuthor uses the sentinel technique — markdown-it parses the block first,
+    // so ## becomes a real <h2>, THEN sentinels are replaced with cw-ins-* spans.
+    const html = renderReview("Intro.", "Intro.\n\n## New Section", [{ start: 8, end: 22, author: "human" }], []);
+    expect(html).toMatch(/<h[12][^>]*>/);   // real heading element, not literal "## "
+    expect(html).toContain("cw-ins-human"); // author-colored insertion
+    expect(html).not.toContain("&gt;&gt;"); // sanity: markers not escaped as text
+  });
+
+  test("renderReview: a proposal block colors its del/ins by author (claude default)", () => {
+    const proposals: ProposalView[] = [{ id: "p1", anchorStart: 0, anchorEnd: 5, replaced: "hello", replacement: "goodbye" }];
+    const html = renderReview("hello", "hello", [], proposals);
+    expect(html).toContain('cw-del-claude');
+    expect(html).toContain('cw-ins-claude');
+  });
 });
 
 import { renderTrackChanges as rtc2 } from "../src/trackChangesModel";