feat(ui): rework streaming output — step timeline, deep-thinking disclosure, tool trows, word fade-in

apps/desktop/src/main/__tests__/chat-marker-cascade-contract.test.ts

@@ -40,18 +40,18 @@ describe('chat Marker shell migration contract (#332 PR2)', () => {
  }
  });
 
- it('keeps the turn container + deferred reasoning chrome (out of scope)', async () => {
+ it('keeps the turn container (out of scope)', async () => {
  const css = await readAllRendererCss();
  for (const selector of [
  // The `.maka-turn` flex/measure container is NOT a marker — it stays.
  '.maka-turn {',
- '.maka-turn-tools',
  '.maka-turn-streaming',
  '.maka-turn[data-search-highlight="true"]',
- // `.maka-turn-thinking` is explicitly deferred (pseudo-element chevron +
- // @starting-style fade don't reduce to leaf utilities); it stays authored.
- '.maka-turn-thinking',
- '.maka-turn-thinking [data-slot="collapsible-trigger"]',
+ // NOTE: `.maka-turn-thinking` and `.maka-turn-tools` were retired by the
+ // streaming UI rework — reasoning now renders through the `DeepThinking`
+ // disclosure (Tailwind-literal chrome + the `maka-text-shimmer` primitive)
+ // and tools through the flat `ToolTrow`, so the hand-authored committed-
+ // turn thinking `<details>` chrome and the tools-section wrapper are gone.
  ]) {
  assert.ok(css.includes(selector), `out-of-scope turn rule "${selector}" must be preserved`);
  }

apps/desktop/src/main/__tests__/chat-status-cluster-layout-contract.test.ts

@@ -21,18 +21,66 @@ describe('chat status cluster layout contract', () => {
  it('keeps alert/status badges in flow between the header and first chat content', async () => {
  const src = await readRepo('packages/ui/src/chat-view.tsx');
 
+ // The cluster div is ALWAYS mounted (streaming-settle polish): it
+ // collapses via the CSS `:empty` height transition instead of conditional
+ // mount/unmount, which used to snap the conversation column up by the
+ // badge-row height the frame a run completed. The badges inside stay
+ // conditional.
  assert.match(
  src,
- /<header className="maka-chat-header">[\s\S]*?<\/header>\s*\{\(props\.sessionStatusBadge \|\| props\.connectionAlert \|\| props\.eventStreamAlert\) && \(/,
+ /<\/header>\s*\{\/\*[\s\S]*?\*\/\}\s*<div className="maka-chat-status-cluster">/,
  'status badges should render after the header, not inside the header toolbar row',
  );
  assert.match(
  src,
- /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\)\}\s*\{isLocalSimulationBackend && \(/,
+ /<div className="maka-chat-status-cluster">\s*\{props\.sessionStatusBadge && /,
+ 'the cluster div must be unconditionally mounted with badges conditional INSIDE (the :empty transition depends on it)',
+ );
+ assert.match(
+ src,
+ /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\{isLocalSimulationBackend && \(/,
  'status badges should stay before the fake-backend banner so normal flow reserves vertical space before first content',
  );
  });
 
+ it('collapses via :empty with tokenized height/opacity transition instead of unmount', async () => {
+ const css = await readRendererContractCss();
+ const body = ruleBody(css, '.maka-chat-status-cluster');
+ assert.match(body, /interpolate-size:\s*allow-keywords/, 'height auto↔0 transition needs interpolate-size');
+ assert.match(body, /transition:[\s\S]*?height var\(--duration-large\)/, 'height must transition on a duration token');
+ const emptyBody = ruleBody(css, '.maka-chat-status-cluster:empty');
+ assert.match(emptyBody, /height:\s*0/);
+ assert.match(emptyBody, /opacity:\s*0/);
+ });
+
+ it('reserves the footer placeholder for every live turn, not only text answers', async () => {
+ // Three-way review (ChatGPT P2): a settled turn ALWAYS mounts a footer
+ // (deriveTurnFooterActions yields regenerate/branch from TurnStatus alone;
+ // materialize emits a timeline item for a step's thinking even with empty
+ // text), so a thinking-only turn settles WITH a footer. The live footer
+ // placeholder must live inside the `streamingText || thinkingText` section
+ // and render unconditionally there — never re-narrowed to streamingText —
+ // so it reserves the footer box for every live turn.
+ //
+ // Groundwork only: this locks the reserved box. It makes the swap
+ // height-neutral where the live section is held to settle (text turns, via
+ // the draining handshake). The textless / thinking-only completion path is
+ // still non-atomic (clears live before the committed footer mounts); that
+ // is tracked in the single-render-path convergence (#642), not asserted
+ // here.
+ const src = await readRepo('packages/ui/src/chat-view.tsx');
+ assert.match(
+ src,
+ /Unconditional \(not gated on streamingText\)[\s\S]*?\*\/\}\s*<div aria-hidden="true" className="mt-0\.5 h-8" \/>/,
+ 'the footer placeholder must render unconditionally inside the live section (covers thinking-only turns)',
+ );
+ assert.doesNotMatch(
+ src,
+ /\{props\.streamingText && <div aria-hidden="true" className="mt-0\.5 h-8" \/>\}/,
+ 'the placeholder must not be re-gated on streamingText alone — that misses thinking-only settle',
+ );
+ });
+
  it('uses an in-flow wrapping row instead of absolute positioning', async () => {
  const css = await readRendererContractCss();
  const body = ruleBody(css, '.maka-chat-status-cluster');

apps/desktop/src/main/__tests__/design-system-governance-406-contract.test.ts

@@ -111,10 +111,20 @@ describe('issue #406 design-system governance contract', () => {
  'maka-toast-enter',
  'maka-toast-exit',
  'maka-processing-sweep',
- 'maka-cursor',
  'maka-list-row-streaming-pulse',
  'maka-pulse',
- 'maka-reasoning-panel-pulse',
+ // Streaming UI rework: the "深度思考" disclosure title + a working trow's
+ // active-tool summary sweep light across the label (functional "still
+ // working" signal), driven by the TextShimmer primitive. The retired ▎
+ // caret's `maka-cursor` is replaced by `maka-stream-fade-in`, the
+ // per-word entrance that signals freshly streamed text.
+ 'maka-text-shimmer',
+ 'maka-stream-fade-in',
+ // Handoff polish: the turn footer toolbar fades in when a live turn
+ // settles (opacity only, into an equal-height placeholder slot) —
+ // functional "the answer is final, actions are now available" signal,
+ // never applied on history-hydration mounts.
+ 'maka-footer-fade-in',
  'maka-shimmer',
  'maka-status-spin',
  'maka-tool-pulse',

apps/desktop/src/main/__tests__/markdown-prose-contract.test.ts

@@ -198,12 +198,13 @@ describe('PROSE-POLISH-13PX-0 contract (#546 Phase B)', () => {
  && !/\.maka-prose\s*>\s*p:nth-last-child/.test(css),
  'structural :nth-last-child prose hacks must not return — they assume a trailing non-markdown child that no longer exists',
  );
- // The streaming caret still needs the trailing paragraph inlined, but
- // scoped to the streaming bubble only.
- assert.match(
- css,
- /\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/,
- 'the caret-inline rule must be scoped to .maka-bubble-streaming so committed messages and .maka-prose reusers (tool results, #546 PR6) keep block paragraphs',
+ // The streaming ▎ caret (and its trailing-<p> inline hack) was retired by
+ // the streaming UI rework — the "still writing" signal is the per-word
+ // fade-in — so the streaming bubble must NOT re-introduce a
+ // `p:last-child { display: inline }` rule that would collapse block spacing.
+ assert.ok(
+ !/\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/.test(css),
+ 'the retired caret-inline hack must not return — the trailing paragraph keeps normal block layout',
  );
  // Negative side of the same contract: an unscoped variant on the
  // committed-message classes would inline the final paragraph of every

apps/desktop/src/main/__tests__/materialize-turns.test.ts

@@ -347,6 +347,122 @@ describe('materializeTurns', () => {
  });
 });
 
+function toolCallStep(turnId: string, ts: number, id: string, stepId: string, toolName = 'Read'): StoredMessage {
+ return { type: 'tool_call', id, turnId, ts, toolName, args: {}, stepId };
+}
+
+function assistantStep(
+ turnId: string,
+ ts: number,
+ id: string,
+ text: string,
+ thinking?: string,
+): StoredMessage {
+ return {
+ type: 'assistant',
+ id,
+ turnId,
+ ts,
+ text,
+ modelId: 'm',
+ ...(thinking !== undefined ? { thinking: { text: thinking } } : {}),
+ } as StoredMessage;
+}
+
+describe('materializeTurns timeline', () => {
+ it('interleaves each step: thinking -> text -> that step’s tools', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a1', 'step one', 'think one'),
+ toolCallStep('t1', 104, 'c2', 'a2'),
+ toolResultMsg('t1', 105, 'c2'),
+ assistantStep('t1', 106, 'a2', 'step two', 'think two'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['thinking', 'text', 'tools', 'thinking', 'text', 'tools']);
+ assert.equal((timeline[0] as { text: string }).text, 'think one');
+ assert.equal((timeline[1] as { text: string }).text, 'step one');
+ assert.equal((timeline[2] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[5] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c2');
+ // Aggregate fields still reflect the concatenated whole for legacy consumers.
+ assert.equal(turns[0]?.assistant?.text, 'step one\n\nstep two');
+ assert.equal(turns[0]?.assistantThinking, 'think one\n\nthink two');
+ });
+
+ it('renders a pure-tool step’s orphan tools before the next step’s answer', () => {
+ // The most common tool turn: step a1 only calls tools (no assistant row
+ // is persisted for it), step a2 delivers the summary. The a1 tools carry
+ // a stepId no assistant row matches — they must still render before the
+ // answer, not park past it as answer-then-tools.
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a2', 'summary', 'think'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'thinking', 'text']);
+ assert.equal((timeline[0] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[2] as { text: string }).text, 'summary');
+ });
+
+ it('legacy call with no stepId sits before the summary text', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallMsg('t1', 101, 'c1', 'Read'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantMsg('t1', 103, 'summary'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'text']);
+ assert.equal((timeline[1] as { text: string }).text, 'summary');
+ });
+
+ it('flushes leftover tools as a trailing group when the turn has no assistant row (abort)', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools']);
+ assert.equal((timeline[0] as { items: { status: string }[] }).items[0]?.status, 'interrupted');
+ });
+
+ it('appends live-only in-flight tools to the timeline tail', () => {
+ const turns = materializeTurns(
+ [userMsg('t1', 100, 'q'), assistantStep('t1', 103, 'a1', 'hi')],
+ [{ toolUseId: 'live-1', toolName: 'Bash', status: 'running', args: {} }],
+ );
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['text', 'tools']);
+ assert.equal((timeline[1] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'live-1');
+ });
+
+ it('merges adjacent thinking blocks and adjacent tool groups', () => {
+ const thinkingOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ assistantStep('t1', 101, 'a1', '', 'first'),
+ assistantStep('t1', 102, 'a2', '', 'second'),
+ ]);
+ const tl1 = thinkingOnly[0]!.timeline;
+ assert.deepEqual(tl1.map((i) => i.kind), ['thinking']);
+ assert.equal((tl1[0] as { text: string }).text, 'first\n\nsecond');
+
+ const toolsOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ assistantStep('t1', 102, 'a1', ''),
+ toolCallStep('t1', 103, 'c2', 'a2'),
+ assistantStep('t1', 104, 'a2', ''),
+ ]);
+ const tl2 = toolsOnly[0]!.timeline;
+ assert.deepEqual(tl2.map((i) => i.kind), ['tools']);
+ assert.equal((tl2[0] as { items: unknown[] }).items.length, 2);
+ });
+});
+
 describe('deriveTurnLineageMap', () => {
  it('derives reverse links without mutating old turns', () => {
  const map = deriveTurnLineageMap([

apps/desktop/src/main/__tests__/smooth-stream.test.ts

@@ -132,7 +132,14 @@ describe('computeFrameAdvance', () => {
  );
  });
 
- it('returns 0 when dt is non-positive', () => {
+ // Regression lock (streaming UI rework, blank-bubble freeze): rAF timestamps
+ // are vsync-aligned and lag the wall clock under IPC delta bursts, so dtMs
+ // clamps to 0 for every tick in the recovery window. Returning 0 left
+ // displayedCount unchanged → the RAF effect never re-armed → the typewriter
+ // died with a full backlog and the answer snapped in at stream end. With
+ // backlog present, a non-positive dt must still advance 1 to keep the
+ // single-owner RAF chain alive.
+ it('advances 1 (not 0) when dt is non-positive but backlog remains — keeps the RAF chain alive', () => {
  assert.equal(
  computeFrameAdvance({
  rawGraphemeCount: 100,
@@ -142,7 +149,7 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
-0,
+1,
  );
  assert.equal(
  computeFrameAdvance({
@@ -153,6 +160,18 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
+ 1,
+ );
+ // …but never invents work: zero backlog still returns 0.
+ assert.equal(
+ computeFrameAdvance({
+ rawGraphemeCount: 10,
+ displayedGraphemeCount: 10,
+ emaCps: 60,
+ dtMs: 0,
+ minCps: 30,
+ maxCps: 400,
+ }),
  0,
  );
  });

apps/desktop/src/main/__tests__/chat-marker-cascade-contract.test.ts

@@ -40,18 +40,18 @@ describe('chat Marker shell migration contract (#332 PR2)', () => {
  }
  });
 
- it('keeps the turn container + deferred reasoning chrome (out of scope)', async () => {
+ it('keeps the turn container (out of scope)', async () => {
  const css = await readAllRendererCss();
  for (const selector of [
  // The `.maka-turn` flex/measure container is NOT a marker — it stays.
  '.maka-turn {',
- '.maka-turn-tools',
  '.maka-turn-streaming',
  '.maka-turn[data-search-highlight="true"]',
- // `.maka-turn-thinking` is explicitly deferred (pseudo-element chevron +
- // @starting-style fade don't reduce to leaf utilities); it stays authored.
- '.maka-turn-thinking',
- '.maka-turn-thinking [data-slot="collapsible-trigger"]',
+ // NOTE: `.maka-turn-thinking` and `.maka-turn-tools` were retired by the
+ // streaming UI rework — reasoning now renders through the `DeepThinking`
+ // disclosure (Tailwind-literal chrome + the `maka-text-shimmer` primitive)
+ // and tools through the flat `ToolTrow`, so the hand-authored committed-
+ // turn thinking `<details>` chrome and the tools-section wrapper are gone.
  ]) {
  assert.ok(css.includes(selector), `out-of-scope turn rule "${selector}" must be preserved`);
  }

apps/desktop/src/main/__tests__/chat-status-cluster-layout-contract.test.ts

@@ -21,18 +21,66 @@ describe('chat status cluster layout contract', () => {
  it('keeps alert/status badges in flow between the header and first chat content', async () => {
  const src = await readRepo('packages/ui/src/chat-view.tsx');
 
+ // The cluster div is ALWAYS mounted (streaming-settle polish): it
+ // collapses via the CSS `:empty` height transition instead of conditional
+ // mount/unmount, which used to snap the conversation column up by the
+ // badge-row height the frame a run completed. The badges inside stay
+ // conditional.
  assert.match(
  src,
- /<header className="maka-chat-header">[\s\S]*?<\/header>\s*\{\(props\.sessionStatusBadge \|\| props\.connectionAlert \|\| props\.eventStreamAlert\) && \(/,
+ /<\/header>\s*\{\/\*[\s\S]*?\*\/\}\s*<div className="maka-chat-status-cluster">/,
  'status badges should render after the header, not inside the header toolbar row',
  );
  assert.match(
  src,
- /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\)\}\s*\{isLocalSimulationBackend && \(/,
+ /<div className="maka-chat-status-cluster">\s*\{props\.sessionStatusBadge && /,
+ 'the cluster div must be unconditionally mounted with badges conditional INSIDE (the :empty transition depends on it)',
+ );
+ assert.match(
+ src,
+ /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\{isLocalSimulationBackend && \(/,
  'status badges should stay before the fake-backend banner so normal flow reserves vertical space before first content',
  );
  });
 
+ it('collapses via :empty with tokenized height/opacity transition instead of unmount', async () => {
+ const css = await readRendererContractCss();
+ const body = ruleBody(css, '.maka-chat-status-cluster');
+ assert.match(body, /interpolate-size:\s*allow-keywords/, 'height auto↔0 transition needs interpolate-size');
+ assert.match(body, /transition:[\s\S]*?height var\(--duration-large\)/, 'height must transition on a duration token');
+ const emptyBody = ruleBody(css, '.maka-chat-status-cluster:empty');
+ assert.match(emptyBody, /height:\s*0/);
+ assert.match(emptyBody, /opacity:\s*0/);
+ });
+
+ it('reserves the footer placeholder for every live turn, not only text answers', async () => {
+ // Three-way review (ChatGPT P2): a settled turn ALWAYS mounts a footer
+ // (deriveTurnFooterActions yields regenerate/branch from TurnStatus alone;
+ // materialize emits a timeline item for a step's thinking even with empty
+ // text), so a thinking-only turn settles WITH a footer. The live footer
+ // placeholder must live inside the `streamingText || thinkingText` section
+ // and render unconditionally there — never re-narrowed to streamingText —
+ // so it reserves the footer box for every live turn.
+ //
+ // Groundwork only: this locks the reserved box. It makes the swap
+ // height-neutral where the live section is held to settle (text turns, via
+ // the draining handshake). The textless / thinking-only completion path is
+ // still non-atomic (clears live before the committed footer mounts); that
+ // is tracked in the single-render-path convergence (#642), not asserted
+ // here.
+ const src = await readRepo('packages/ui/src/chat-view.tsx');
+ assert.match(
+ src,
+ /Unconditional \(not gated on streamingText\)[\s\S]*?\*\/\}\s*<div aria-hidden="true" className="mt-0\.5 h-8" \/>/,
+ 'the footer placeholder must render unconditionally inside the live section (covers thinking-only turns)',
+ );
+ assert.doesNotMatch(
+ src,
+ /\{props\.streamingText && <div aria-hidden="true" className="mt-0\.5 h-8" \/>\}/,
+ 'the placeholder must not be re-gated on streamingText alone — that misses thinking-only settle',
+ );
+ });
+
  it('uses an in-flow wrapping row instead of absolute positioning', async () => {
  const css = await readRendererContractCss();
  const body = ruleBody(css, '.maka-chat-status-cluster');

apps/desktop/src/main/__tests__/design-system-governance-406-contract.test.ts

@@ -111,10 +111,20 @@ describe('issue #406 design-system governance contract', () => {
  'maka-toast-enter',
  'maka-toast-exit',
  'maka-processing-sweep',
- 'maka-cursor',
  'maka-list-row-streaming-pulse',
  'maka-pulse',
- 'maka-reasoning-panel-pulse',
+ // Streaming UI rework: the "深度思考" disclosure title + a working trow's
+ // active-tool summary sweep light across the label (functional "still
+ // working" signal), driven by the TextShimmer primitive. The retired ▎
+ // caret's `maka-cursor` is replaced by `maka-stream-fade-in`, the
+ // per-word entrance that signals freshly streamed text.
+ 'maka-text-shimmer',
+ 'maka-stream-fade-in',
+ // Handoff polish: the turn footer toolbar fades in when a live turn
+ // settles (opacity only, into an equal-height placeholder slot) —
+ // functional "the answer is final, actions are now available" signal,
+ // never applied on history-hydration mounts.
+ 'maka-footer-fade-in',
  'maka-shimmer',
  'maka-status-spin',
  'maka-tool-pulse',

apps/desktop/src/main/__tests__/markdown-prose-contract.test.ts

@@ -198,12 +198,13 @@ describe('PROSE-POLISH-13PX-0 contract (#546 Phase B)', () => {
  && !/\.maka-prose\s*>\s*p:nth-last-child/.test(css),
  'structural :nth-last-child prose hacks must not return — they assume a trailing non-markdown child that no longer exists',
  );
- // The streaming caret still needs the trailing paragraph inlined, but
- // scoped to the streaming bubble only.
- assert.match(
- css,
- /\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/,
- 'the caret-inline rule must be scoped to .maka-bubble-streaming so committed messages and .maka-prose reusers (tool results, #546 PR6) keep block paragraphs',
+ // The streaming ▎ caret (and its trailing-<p> inline hack) was retired by
+ // the streaming UI rework — the "still writing" signal is the per-word
+ // fade-in — so the streaming bubble must NOT re-introduce a
+ // `p:last-child { display: inline }` rule that would collapse block spacing.
+ assert.ok(
+ !/\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/.test(css),
+ 'the retired caret-inline hack must not return — the trailing paragraph keeps normal block layout',
  );
  // Negative side of the same contract: an unscoped variant on the
  // committed-message classes would inline the final paragraph of every

apps/desktop/src/main/__tests__/materialize-turns.test.ts

@@ -347,6 +347,122 @@ describe('materializeTurns', () => {
  });
 });
 
+function toolCallStep(turnId: string, ts: number, id: string, stepId: string, toolName = 'Read'): StoredMessage {
+ return { type: 'tool_call', id, turnId, ts, toolName, args: {}, stepId };
+}
+
+function assistantStep(
+ turnId: string,
+ ts: number,
+ id: string,
+ text: string,
+ thinking?: string,
+): StoredMessage {
+ return {
+ type: 'assistant',
+ id,
+ turnId,
+ ts,
+ text,
+ modelId: 'm',
+ ...(thinking !== undefined ? { thinking: { text: thinking } } : {}),
+ } as StoredMessage;
+}
+
+describe('materializeTurns timeline', () => {
+ it('interleaves each step: thinking -> text -> that step’s tools', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a1', 'step one', 'think one'),
+ toolCallStep('t1', 104, 'c2', 'a2'),
+ toolResultMsg('t1', 105, 'c2'),
+ assistantStep('t1', 106, 'a2', 'step two', 'think two'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['thinking', 'text', 'tools', 'thinking', 'text', 'tools']);
+ assert.equal((timeline[0] as { text: string }).text, 'think one');
+ assert.equal((timeline[1] as { text: string }).text, 'step one');
+ assert.equal((timeline[2] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[5] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c2');
+ // Aggregate fields still reflect the concatenated whole for legacy consumers.
+ assert.equal(turns[0]?.assistant?.text, 'step one\n\nstep two');
+ assert.equal(turns[0]?.assistantThinking, 'think one\n\nthink two');
+ });
+
+ it('renders a pure-tool step’s orphan tools before the next step’s answer', () => {
+ // The most common tool turn: step a1 only calls tools (no assistant row
+ // is persisted for it), step a2 delivers the summary. The a1 tools carry
+ // a stepId no assistant row matches — they must still render before the
+ // answer, not park past it as answer-then-tools.
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a2', 'summary', 'think'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'thinking', 'text']);
+ assert.equal((timeline[0] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[2] as { text: string }).text, 'summary');
+ });
+
+ it('legacy call with no stepId sits before the summary text', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallMsg('t1', 101, 'c1', 'Read'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantMsg('t1', 103, 'summary'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'text']);
+ assert.equal((timeline[1] as { text: string }).text, 'summary');
+ });
+
+ it('flushes leftover tools as a trailing group when the turn has no assistant row (abort)', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools']);
+ assert.equal((timeline[0] as { items: { status: string }[] }).items[0]?.status, 'interrupted');
+ });
+
+ it('appends live-only in-flight tools to the timeline tail', () => {
+ const turns = materializeTurns(
+ [userMsg('t1', 100, 'q'), assistantStep('t1', 103, 'a1', 'hi')],
+ [{ toolUseId: 'live-1', toolName: 'Bash', status: 'running', args: {} }],
+ );
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['text', 'tools']);
+ assert.equal((timeline[1] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'live-1');
+ });
+
+ it('merges adjacent thinking blocks and adjacent tool groups', () => {
+ const thinkingOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ assistantStep('t1', 101, 'a1', '', 'first'),
+ assistantStep('t1', 102, 'a2', '', 'second'),
+ ]);
+ const tl1 = thinkingOnly[0]!.timeline;
+ assert.deepEqual(tl1.map((i) => i.kind), ['thinking']);
+ assert.equal((tl1[0] as { text: string }).text, 'first\n\nsecond');
+
+ const toolsOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ assistantStep('t1', 102, 'a1', ''),
+ toolCallStep('t1', 103, 'c2', 'a2'),
+ assistantStep('t1', 104, 'a2', ''),
+ ]);
+ const tl2 = toolsOnly[0]!.timeline;
+ assert.deepEqual(tl2.map((i) => i.kind), ['tools']);
+ assert.equal((tl2[0] as { items: unknown[] }).items.length, 2);
+ });
+});
+
 describe('deriveTurnLineageMap', () => {
  it('derives reverse links without mutating old turns', () => {
  const map = deriveTurnLineageMap([

apps/desktop/src/main/__tests__/smooth-stream.test.ts

@@ -132,7 +132,14 @@ describe('computeFrameAdvance', () => {
  );
  });
 
- it('returns 0 when dt is non-positive', () => {
+ // Regression lock (streaming UI rework, blank-bubble freeze): rAF timestamps
+ // are vsync-aligned and lag the wall clock under IPC delta bursts, so dtMs
+ // clamps to 0 for every tick in the recovery window. Returning 0 left
+ // displayedCount unchanged → the RAF effect never re-armed → the typewriter
+ // died with a full backlog and the answer snapped in at stream end. With
+ // backlog present, a non-positive dt must still advance 1 to keep the
+ // single-owner RAF chain alive.
+ it('advances 1 (not 0) when dt is non-positive but backlog remains — keeps the RAF chain alive', () => {
  assert.equal(
  computeFrameAdvance({
  rawGraphemeCount: 100,
@@ -142,7 +149,7 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
-0,
+1,
  );
  assert.equal(
  computeFrameAdvance({
@@ -153,6 +160,18 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
+ 1,
+ );
+ // …but never invents work: zero backlog still returns 0.
+ assert.equal(
+ computeFrameAdvance({
+ rawGraphemeCount: 10,
+ displayedGraphemeCount: 10,
+ emaCps: 60,
+ dtMs: 0,
+ minCps: 30,
+ maxCps: 400,
+ }),
  0,
  );
  });

apps/desktop/src/main/__tests__/chat-marker-cascade-contract.test.ts

@@ -40,18 +40,18 @@ describe('chat Marker shell migration contract (#332 PR2)', () => {
  }
  });
 
- it('keeps the turn container + deferred reasoning chrome (out of scope)', async () => {
+ it('keeps the turn container (out of scope)', async () => {
  const css = await readAllRendererCss();
  for (const selector of [
  // The `.maka-turn` flex/measure container is NOT a marker — it stays.
  '.maka-turn {',
- '.maka-turn-tools',
  '.maka-turn-streaming',
  '.maka-turn[data-search-highlight="true"]',
- // `.maka-turn-thinking` is explicitly deferred (pseudo-element chevron +
- // @starting-style fade don't reduce to leaf utilities); it stays authored.
- '.maka-turn-thinking',
- '.maka-turn-thinking [data-slot="collapsible-trigger"]',
+ // NOTE: `.maka-turn-thinking` and `.maka-turn-tools` were retired by the
+ // streaming UI rework — reasoning now renders through the `DeepThinking`
+ // disclosure (Tailwind-literal chrome + the `maka-text-shimmer` primitive)
+ // and tools through the flat `ToolTrow`, so the hand-authored committed-
+ // turn thinking `<details>` chrome and the tools-section wrapper are gone.
  ]) {
  assert.ok(css.includes(selector), `out-of-scope turn rule "${selector}" must be preserved`);
  }

apps/desktop/src/main/__tests__/chat-status-cluster-layout-contract.test.ts

@@ -21,18 +21,66 @@ describe('chat status cluster layout contract', () => {
  it('keeps alert/status badges in flow between the header and first chat content', async () => {
  const src = await readRepo('packages/ui/src/chat-view.tsx');
 
+ // The cluster div is ALWAYS mounted (streaming-settle polish): it
+ // collapses via the CSS `:empty` height transition instead of conditional
+ // mount/unmount, which used to snap the conversation column up by the
+ // badge-row height the frame a run completed. The badges inside stay
+ // conditional.
  assert.match(
  src,
- /<header className="maka-chat-header">[\s\S]*?<\/header>\s*\{\(props\.sessionStatusBadge \|\| props\.connectionAlert \|\| props\.eventStreamAlert\) && \(/,
+ /<\/header>\s*\{\/\*[\s\S]*?\*\/\}\s*<div className="maka-chat-status-cluster">/,
  'status badges should render after the header, not inside the header toolbar row',
  );
  assert.match(
  src,
- /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\)\}\s*\{isLocalSimulationBackend && \(/,
+ /<div className="maka-chat-status-cluster">\s*\{props\.sessionStatusBadge && /,
+ 'the cluster div must be unconditionally mounted with badges conditional INSIDE (the :empty transition depends on it)',
+ );
+ assert.match(
+ src,
+ /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\{isLocalSimulationBackend && \(/,
  'status badges should stay before the fake-backend banner so normal flow reserves vertical space before first content',
  );
  });
 
+ it('collapses via :empty with tokenized height/opacity transition instead of unmount', async () => {
+ const css = await readRendererContractCss();
+ const body = ruleBody(css, '.maka-chat-status-cluster');
+ assert.match(body, /interpolate-size:\s*allow-keywords/, 'height auto↔0 transition needs interpolate-size');
+ assert.match(body, /transition:[\s\S]*?height var\(--duration-large\)/, 'height must transition on a duration token');
+ const emptyBody = ruleBody(css, '.maka-chat-status-cluster:empty');
+ assert.match(emptyBody, /height:\s*0/);
+ assert.match(emptyBody, /opacity:\s*0/);
+ });
+
+ it('reserves the footer placeholder for every live turn, not only text answers', async () => {
+ // Three-way review (ChatGPT P2): a settled turn ALWAYS mounts a footer
+ // (deriveTurnFooterActions yields regenerate/branch from TurnStatus alone;
+ // materialize emits a timeline item for a step's thinking even with empty
+ // text), so a thinking-only turn settles WITH a footer. The live footer
+ // placeholder must live inside the `streamingText || thinkingText` section
+ // and render unconditionally there — never re-narrowed to streamingText —
+ // so it reserves the footer box for every live turn.
+ //
+ // Groundwork only: this locks the reserved box. It makes the swap
+ // height-neutral where the live section is held to settle (text turns, via
+ // the draining handshake). The textless / thinking-only completion path is
+ // still non-atomic (clears live before the committed footer mounts); that
+ // is tracked in the single-render-path convergence (#642), not asserted
+ // here.
+ const src = await readRepo('packages/ui/src/chat-view.tsx');
+ assert.match(
+ src,
+ /Unconditional \(not gated on streamingText\)[\s\S]*?\*\/\}\s*<div aria-hidden="true" className="mt-0\.5 h-8" \/>/,
+ 'the footer placeholder must render unconditionally inside the live section (covers thinking-only turns)',
+ );
+ assert.doesNotMatch(
+ src,
+ /\{props\.streamingText && <div aria-hidden="true" className="mt-0\.5 h-8" \/>\}/,
+ 'the placeholder must not be re-gated on streamingText alone — that misses thinking-only settle',
+ );
+ });
+
  it('uses an in-flow wrapping row instead of absolute positioning', async () => {
  const css = await readRendererContractCss();
  const body = ruleBody(css, '.maka-chat-status-cluster');

apps/desktop/src/main/__tests__/design-system-governance-406-contract.test.ts

@@ -111,10 +111,20 @@ describe('issue #406 design-system governance contract', () => {
  'maka-toast-enter',
  'maka-toast-exit',
  'maka-processing-sweep',
- 'maka-cursor',
  'maka-list-row-streaming-pulse',
  'maka-pulse',
- 'maka-reasoning-panel-pulse',
+ // Streaming UI rework: the "深度思考" disclosure title + a working trow's
+ // active-tool summary sweep light across the label (functional "still
+ // working" signal), driven by the TextShimmer primitive. The retired ▎
+ // caret's `maka-cursor` is replaced by `maka-stream-fade-in`, the
+ // per-word entrance that signals freshly streamed text.
+ 'maka-text-shimmer',
+ 'maka-stream-fade-in',
+ // Handoff polish: the turn footer toolbar fades in when a live turn
+ // settles (opacity only, into an equal-height placeholder slot) —
+ // functional "the answer is final, actions are now available" signal,
+ // never applied on history-hydration mounts.
+ 'maka-footer-fade-in',
  'maka-shimmer',
  'maka-status-spin',
  'maka-tool-pulse',

apps/desktop/src/main/__tests__/markdown-prose-contract.test.ts

@@ -198,12 +198,13 @@ describe('PROSE-POLISH-13PX-0 contract (#546 Phase B)', () => {
  && !/\.maka-prose\s*>\s*p:nth-last-child/.test(css),
  'structural :nth-last-child prose hacks must not return — they assume a trailing non-markdown child that no longer exists',
  );
- // The streaming caret still needs the trailing paragraph inlined, but
- // scoped to the streaming bubble only.
- assert.match(
- css,
- /\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/,
- 'the caret-inline rule must be scoped to .maka-bubble-streaming so committed messages and .maka-prose reusers (tool results, #546 PR6) keep block paragraphs',
+ // The streaming ▎ caret (and its trailing-<p> inline hack) was retired by
+ // the streaming UI rework — the "still writing" signal is the per-word
+ // fade-in — so the streaming bubble must NOT re-introduce a
+ // `p:last-child { display: inline }` rule that would collapse block spacing.
+ assert.ok(
+ !/\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/.test(css),
+ 'the retired caret-inline hack must not return — the trailing paragraph keeps normal block layout',
  );
  // Negative side of the same contract: an unscoped variant on the
  // committed-message classes would inline the final paragraph of every

apps/desktop/src/main/__tests__/materialize-turns.test.ts

@@ -347,6 +347,122 @@ describe('materializeTurns', () => {
  });
 });
 
+function toolCallStep(turnId: string, ts: number, id: string, stepId: string, toolName = 'Read'): StoredMessage {
+ return { type: 'tool_call', id, turnId, ts, toolName, args: {}, stepId };
+}
+
+function assistantStep(
+ turnId: string,
+ ts: number,
+ id: string,
+ text: string,
+ thinking?: string,
+): StoredMessage {
+ return {
+ type: 'assistant',
+ id,
+ turnId,
+ ts,
+ text,
+ modelId: 'm',
+ ...(thinking !== undefined ? { thinking: { text: thinking } } : {}),
+ } as StoredMessage;
+}
+
+describe('materializeTurns timeline', () => {
+ it('interleaves each step: thinking -> text -> that step’s tools', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a1', 'step one', 'think one'),
+ toolCallStep('t1', 104, 'c2', 'a2'),
+ toolResultMsg('t1', 105, 'c2'),
+ assistantStep('t1', 106, 'a2', 'step two', 'think two'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['thinking', 'text', 'tools', 'thinking', 'text', 'tools']);
+ assert.equal((timeline[0] as { text: string }).text, 'think one');
+ assert.equal((timeline[1] as { text: string }).text, 'step one');
+ assert.equal((timeline[2] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[5] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c2');
+ // Aggregate fields still reflect the concatenated whole for legacy consumers.
+ assert.equal(turns[0]?.assistant?.text, 'step one\n\nstep two');
+ assert.equal(turns[0]?.assistantThinking, 'think one\n\nthink two');
+ });
+
+ it('renders a pure-tool step’s orphan tools before the next step’s answer', () => {
+ // The most common tool turn: step a1 only calls tools (no assistant row
+ // is persisted for it), step a2 delivers the summary. The a1 tools carry
+ // a stepId no assistant row matches — they must still render before the
+ // answer, not park past it as answer-then-tools.
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a2', 'summary', 'think'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'thinking', 'text']);
+ assert.equal((timeline[0] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[2] as { text: string }).text, 'summary');
+ });
+
+ it('legacy call with no stepId sits before the summary text', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallMsg('t1', 101, 'c1', 'Read'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantMsg('t1', 103, 'summary'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'text']);
+ assert.equal((timeline[1] as { text: string }).text, 'summary');
+ });
+
+ it('flushes leftover tools as a trailing group when the turn has no assistant row (abort)', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools']);
+ assert.equal((timeline[0] as { items: { status: string }[] }).items[0]?.status, 'interrupted');
+ });
+
+ it('appends live-only in-flight tools to the timeline tail', () => {
+ const turns = materializeTurns(
+ [userMsg('t1', 100, 'q'), assistantStep('t1', 103, 'a1', 'hi')],
+ [{ toolUseId: 'live-1', toolName: 'Bash', status: 'running', args: {} }],
+ );
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['text', 'tools']);
+ assert.equal((timeline[1] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'live-1');
+ });
+
+ it('merges adjacent thinking blocks and adjacent tool groups', () => {
+ const thinkingOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ assistantStep('t1', 101, 'a1', '', 'first'),
+ assistantStep('t1', 102, 'a2', '', 'second'),
+ ]);
+ const tl1 = thinkingOnly[0]!.timeline;
+ assert.deepEqual(tl1.map((i) => i.kind), ['thinking']);
+ assert.equal((tl1[0] as { text: string }).text, 'first\n\nsecond');
+
+ const toolsOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ assistantStep('t1', 102, 'a1', ''),
+ toolCallStep('t1', 103, 'c2', 'a2'),
+ assistantStep('t1', 104, 'a2', ''),
+ ]);
+ const tl2 = toolsOnly[0]!.timeline;
+ assert.deepEqual(tl2.map((i) => i.kind), ['tools']);
+ assert.equal((tl2[0] as { items: unknown[] }).items.length, 2);
+ });
+});
+
 describe('deriveTurnLineageMap', () => {
  it('derives reverse links without mutating old turns', () => {
  const map = deriveTurnLineageMap([

apps/desktop/src/main/__tests__/smooth-stream.test.ts

@@ -132,7 +132,14 @@ describe('computeFrameAdvance', () => {
  );
  });
 
- it('returns 0 when dt is non-positive', () => {
+ // Regression lock (streaming UI rework, blank-bubble freeze): rAF timestamps
+ // are vsync-aligned and lag the wall clock under IPC delta bursts, so dtMs
+ // clamps to 0 for every tick in the recovery window. Returning 0 left
+ // displayedCount unchanged → the RAF effect never re-armed → the typewriter
+ // died with a full backlog and the answer snapped in at stream end. With
+ // backlog present, a non-positive dt must still advance 1 to keep the
+ // single-owner RAF chain alive.
+ it('advances 1 (not 0) when dt is non-positive but backlog remains — keeps the RAF chain alive', () => {
  assert.equal(
  computeFrameAdvance({
  rawGraphemeCount: 100,
@@ -142,7 +149,7 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
-0,
+1,
  );
  assert.equal(
  computeFrameAdvance({
@@ -153,6 +160,18 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
+ 1,
+ );
+ // …but never invents work: zero backlog still returns 0.
+ assert.equal(
+ computeFrameAdvance({
+ rawGraphemeCount: 10,
+ displayedGraphemeCount: 10,
+ emaCps: 60,
+ dtMs: 0,
+ minCps: 30,
+ maxCps: 400,
+ }),
  0,
  );
  });

apps/desktop/src/main/__tests__/chat-marker-cascade-contract.test.ts

@@ -40,18 +40,18 @@ describe('chat Marker shell migration contract (#332 PR2)', () => {
  }
  });
 
- it('keeps the turn container + deferred reasoning chrome (out of scope)', async () => {
+ it('keeps the turn container (out of scope)', async () => {
  const css = await readAllRendererCss();
  for (const selector of [
  // The `.maka-turn` flex/measure container is NOT a marker — it stays.
  '.maka-turn {',
- '.maka-turn-tools',
  '.maka-turn-streaming',
  '.maka-turn[data-search-highlight="true"]',
- // `.maka-turn-thinking` is explicitly deferred (pseudo-element chevron +
- // @starting-style fade don't reduce to leaf utilities); it stays authored.
- '.maka-turn-thinking',
- '.maka-turn-thinking [data-slot="collapsible-trigger"]',
+ // NOTE: `.maka-turn-thinking` and `.maka-turn-tools` were retired by the
+ // streaming UI rework — reasoning now renders through the `DeepThinking`
+ // disclosure (Tailwind-literal chrome + the `maka-text-shimmer` primitive)
+ // and tools through the flat `ToolTrow`, so the hand-authored committed-
+ // turn thinking `<details>` chrome and the tools-section wrapper are gone.
  ]) {
  assert.ok(css.includes(selector), `out-of-scope turn rule "${selector}" must be preserved`);
  }

apps/desktop/src/main/__tests__/chat-status-cluster-layout-contract.test.ts

@@ -21,18 +21,66 @@ describe('chat status cluster layout contract', () => {
  it('keeps alert/status badges in flow between the header and first chat content', async () => {
  const src = await readRepo('packages/ui/src/chat-view.tsx');
 
+ // The cluster div is ALWAYS mounted (streaming-settle polish): it
+ // collapses via the CSS `:empty` height transition instead of conditional
+ // mount/unmount, which used to snap the conversation column up by the
+ // badge-row height the frame a run completed. The badges inside stay
+ // conditional.
  assert.match(
  src,
- /<header className="maka-chat-header">[\s\S]*?<\/header>\s*\{\(props\.sessionStatusBadge \|\| props\.connectionAlert \|\| props\.eventStreamAlert\) && \(/,
+ /<\/header>\s*\{\/\*[\s\S]*?\*\/\}\s*<div className="maka-chat-status-cluster">/,
  'status badges should render after the header, not inside the header toolbar row',
  );
  assert.match(
  src,
- /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\)\}\s*\{isLocalSimulationBackend && \(/,
+ /<div className="maka-chat-status-cluster">\s*\{props\.sessionStatusBadge && /,
+ 'the cluster div must be unconditionally mounted with badges conditional INSIDE (the :empty transition depends on it)',
+ );
+ assert.match(
+ src,
+ /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\{isLocalSimulationBackend && \(/,
  'status badges should stay before the fake-backend banner so normal flow reserves vertical space before first content',
  );
  });
 
+ it('collapses via :empty with tokenized height/opacity transition instead of unmount', async () => {
+ const css = await readRendererContractCss();
+ const body = ruleBody(css, '.maka-chat-status-cluster');
+ assert.match(body, /interpolate-size:\s*allow-keywords/, 'height auto↔0 transition needs interpolate-size');
+ assert.match(body, /transition:[\s\S]*?height var\(--duration-large\)/, 'height must transition on a duration token');
+ const emptyBody = ruleBody(css, '.maka-chat-status-cluster:empty');
+ assert.match(emptyBody, /height:\s*0/);
+ assert.match(emptyBody, /opacity:\s*0/);
+ });
+
+ it('reserves the footer placeholder for every live turn, not only text answers', async () => {
+ // Three-way review (ChatGPT P2): a settled turn ALWAYS mounts a footer
+ // (deriveTurnFooterActions yields regenerate/branch from TurnStatus alone;
+ // materialize emits a timeline item for a step's thinking even with empty
+ // text), so a thinking-only turn settles WITH a footer. The live footer
+ // placeholder must live inside the `streamingText || thinkingText` section
+ // and render unconditionally there — never re-narrowed to streamingText —
+ // so it reserves the footer box for every live turn.
+ //
+ // Groundwork only: this locks the reserved box. It makes the swap
+ // height-neutral where the live section is held to settle (text turns, via
+ // the draining handshake). The textless / thinking-only completion path is
+ // still non-atomic (clears live before the committed footer mounts); that
+ // is tracked in the single-render-path convergence (#642), not asserted
+ // here.
+ const src = await readRepo('packages/ui/src/chat-view.tsx');
+ assert.match(
+ src,
+ /Unconditional \(not gated on streamingText\)[\s\S]*?\*\/\}\s*<div aria-hidden="true" className="mt-0\.5 h-8" \/>/,
+ 'the footer placeholder must render unconditionally inside the live section (covers thinking-only turns)',
+ );
+ assert.doesNotMatch(
+ src,
+ /\{props\.streamingText && <div aria-hidden="true" className="mt-0\.5 h-8" \/>\}/,
+ 'the placeholder must not be re-gated on streamingText alone — that misses thinking-only settle',
+ );
+ });
+
  it('uses an in-flow wrapping row instead of absolute positioning', async () => {
  const css = await readRendererContractCss();
  const body = ruleBody(css, '.maka-chat-status-cluster');

apps/desktop/src/main/__tests__/design-system-governance-406-contract.test.ts

@@ -111,10 +111,20 @@ describe('issue #406 design-system governance contract', () => {
  'maka-toast-enter',
  'maka-toast-exit',
  'maka-processing-sweep',
- 'maka-cursor',
  'maka-list-row-streaming-pulse',
  'maka-pulse',
- 'maka-reasoning-panel-pulse',
+ // Streaming UI rework: the "深度思考" disclosure title + a working trow's
+ // active-tool summary sweep light across the label (functional "still
+ // working" signal), driven by the TextShimmer primitive. The retired ▎
+ // caret's `maka-cursor` is replaced by `maka-stream-fade-in`, the
+ // per-word entrance that signals freshly streamed text.
+ 'maka-text-shimmer',
+ 'maka-stream-fade-in',
+ // Handoff polish: the turn footer toolbar fades in when a live turn
+ // settles (opacity only, into an equal-height placeholder slot) —
+ // functional "the answer is final, actions are now available" signal,
+ // never applied on history-hydration mounts.
+ 'maka-footer-fade-in',
  'maka-shimmer',
  'maka-status-spin',
  'maka-tool-pulse',

apps/desktop/src/main/__tests__/markdown-prose-contract.test.ts

@@ -198,12 +198,13 @@ describe('PROSE-POLISH-13PX-0 contract (#546 Phase B)', () => {
  && !/\.maka-prose\s*>\s*p:nth-last-child/.test(css),
  'structural :nth-last-child prose hacks must not return — they assume a trailing non-markdown child that no longer exists',
  );
- // The streaming caret still needs the trailing paragraph inlined, but
- // scoped to the streaming bubble only.
- assert.match(
- css,
- /\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/,
- 'the caret-inline rule must be scoped to .maka-bubble-streaming so committed messages and .maka-prose reusers (tool results, #546 PR6) keep block paragraphs',
+ // The streaming ▎ caret (and its trailing-<p> inline hack) was retired by
+ // the streaming UI rework — the "still writing" signal is the per-word
+ // fade-in — so the streaming bubble must NOT re-introduce a
+ // `p:last-child { display: inline }` rule that would collapse block spacing.
+ assert.ok(
+ !/\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/.test(css),
+ 'the retired caret-inline hack must not return — the trailing paragraph keeps normal block layout',
  );
  // Negative side of the same contract: an unscoped variant on the
  // committed-message classes would inline the final paragraph of every

apps/desktop/src/main/__tests__/materialize-turns.test.ts

@@ -347,6 +347,122 @@ describe('materializeTurns', () => {
  });
 });
 
+function toolCallStep(turnId: string, ts: number, id: string, stepId: string, toolName = 'Read'): StoredMessage {
+ return { type: 'tool_call', id, turnId, ts, toolName, args: {}, stepId };
+}
+
+function assistantStep(
+ turnId: string,
+ ts: number,
+ id: string,
+ text: string,
+ thinking?: string,
+): StoredMessage {
+ return {
+ type: 'assistant',
+ id,
+ turnId,
+ ts,
+ text,
+ modelId: 'm',
+ ...(thinking !== undefined ? { thinking: { text: thinking } } : {}),
+ } as StoredMessage;
+}
+
+describe('materializeTurns timeline', () => {
+ it('interleaves each step: thinking -> text -> that step’s tools', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a1', 'step one', 'think one'),
+ toolCallStep('t1', 104, 'c2', 'a2'),
+ toolResultMsg('t1', 105, 'c2'),
+ assistantStep('t1', 106, 'a2', 'step two', 'think two'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['thinking', 'text', 'tools', 'thinking', 'text', 'tools']);
+ assert.equal((timeline[0] as { text: string }).text, 'think one');
+ assert.equal((timeline[1] as { text: string }).text, 'step one');
+ assert.equal((timeline[2] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[5] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c2');
+ // Aggregate fields still reflect the concatenated whole for legacy consumers.
+ assert.equal(turns[0]?.assistant?.text, 'step one\n\nstep two');
+ assert.equal(turns[0]?.assistantThinking, 'think one\n\nthink two');
+ });
+
+ it('renders a pure-tool step’s orphan tools before the next step’s answer', () => {
+ // The most common tool turn: step a1 only calls tools (no assistant row
+ // is persisted for it), step a2 delivers the summary. The a1 tools carry
+ // a stepId no assistant row matches — they must still render before the
+ // answer, not park past it as answer-then-tools.
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a2', 'summary', 'think'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'thinking', 'text']);
+ assert.equal((timeline[0] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[2] as { text: string }).text, 'summary');
+ });
+
+ it('legacy call with no stepId sits before the summary text', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallMsg('t1', 101, 'c1', 'Read'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantMsg('t1', 103, 'summary'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'text']);
+ assert.equal((timeline[1] as { text: string }).text, 'summary');
+ });
+
+ it('flushes leftover tools as a trailing group when the turn has no assistant row (abort)', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools']);
+ assert.equal((timeline[0] as { items: { status: string }[] }).items[0]?.status, 'interrupted');
+ });
+
+ it('appends live-only in-flight tools to the timeline tail', () => {
+ const turns = materializeTurns(
+ [userMsg('t1', 100, 'q'), assistantStep('t1', 103, 'a1', 'hi')],
+ [{ toolUseId: 'live-1', toolName: 'Bash', status: 'running', args: {} }],
+ );
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['text', 'tools']);
+ assert.equal((timeline[1] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'live-1');
+ });
+
+ it('merges adjacent thinking blocks and adjacent tool groups', () => {
+ const thinkingOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ assistantStep('t1', 101, 'a1', '', 'first'),
+ assistantStep('t1', 102, 'a2', '', 'second'),
+ ]);
+ const tl1 = thinkingOnly[0]!.timeline;
+ assert.deepEqual(tl1.map((i) => i.kind), ['thinking']);
+ assert.equal((tl1[0] as { text: string }).text, 'first\n\nsecond');
+
+ const toolsOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ assistantStep('t1', 102, 'a1', ''),
+ toolCallStep('t1', 103, 'c2', 'a2'),
+ assistantStep('t1', 104, 'a2', ''),
+ ]);
+ const tl2 = toolsOnly[0]!.timeline;
+ assert.deepEqual(tl2.map((i) => i.kind), ['tools']);
+ assert.equal((tl2[0] as { items: unknown[] }).items.length, 2);
+ });
+});
+
 describe('deriveTurnLineageMap', () => {
  it('derives reverse links without mutating old turns', () => {
  const map = deriveTurnLineageMap([

apps/desktop/src/main/__tests__/smooth-stream.test.ts

@@ -132,7 +132,14 @@ describe('computeFrameAdvance', () => {
  );
  });
 
- it('returns 0 when dt is non-positive', () => {
+ // Regression lock (streaming UI rework, blank-bubble freeze): rAF timestamps
+ // are vsync-aligned and lag the wall clock under IPC delta bursts, so dtMs
+ // clamps to 0 for every tick in the recovery window. Returning 0 left
+ // displayedCount unchanged → the RAF effect never re-armed → the typewriter
+ // died with a full backlog and the answer snapped in at stream end. With
+ // backlog present, a non-positive dt must still advance 1 to keep the
+ // single-owner RAF chain alive.
+ it('advances 1 (not 0) when dt is non-positive but backlog remains — keeps the RAF chain alive', () => {
  assert.equal(
  computeFrameAdvance({
  rawGraphemeCount: 100,
@@ -142,7 +149,7 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
-0,
+1,
  );
  assert.equal(
  computeFrameAdvance({
@@ -153,6 +160,18 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
+ 1,
+ );
+ // …but never invents work: zero backlog still returns 0.
+ assert.equal(
+ computeFrameAdvance({
+ rawGraphemeCount: 10,
+ displayedGraphemeCount: 10,
+ emaCps: 60,
+ dtMs: 0,
+ minCps: 30,
+ maxCps: 400,
+ }),
  0,
  );
  });

apps/desktop/src/main/__tests__/chat-marker-cascade-contract.test.ts

@@ -40,18 +40,18 @@ describe('chat Marker shell migration contract (#332 PR2)', () => {
  }
  });
 
- it('keeps the turn container + deferred reasoning chrome (out of scope)', async () => {
+ it('keeps the turn container (out of scope)', async () => {
  const css = await readAllRendererCss();
  for (const selector of [
  // The `.maka-turn` flex/measure container is NOT a marker — it stays.
  '.maka-turn {',
- '.maka-turn-tools',
  '.maka-turn-streaming',
  '.maka-turn[data-search-highlight="true"]',
- // `.maka-turn-thinking` is explicitly deferred (pseudo-element chevron +
- // @starting-style fade don't reduce to leaf utilities); it stays authored.
- '.maka-turn-thinking',
- '.maka-turn-thinking [data-slot="collapsible-trigger"]',
+ // NOTE: `.maka-turn-thinking` and `.maka-turn-tools` were retired by the
+ // streaming UI rework — reasoning now renders through the `DeepThinking`
+ // disclosure (Tailwind-literal chrome + the `maka-text-shimmer` primitive)
+ // and tools through the flat `ToolTrow`, so the hand-authored committed-
+ // turn thinking `<details>` chrome and the tools-section wrapper are gone.
  ]) {
  assert.ok(css.includes(selector), `out-of-scope turn rule "${selector}" must be preserved`);
  }

apps/desktop/src/main/__tests__/chat-status-cluster-layout-contract.test.ts

@@ -21,18 +21,66 @@ describe('chat status cluster layout contract', () => {
  it('keeps alert/status badges in flow between the header and first chat content', async () => {
  const src = await readRepo('packages/ui/src/chat-view.tsx');
 
+ // The cluster div is ALWAYS mounted (streaming-settle polish): it
+ // collapses via the CSS `:empty` height transition instead of conditional
+ // mount/unmount, which used to snap the conversation column up by the
+ // badge-row height the frame a run completed. The badges inside stay
+ // conditional.
  assert.match(
  src,
- /<header className="maka-chat-header">[\s\S]*?<\/header>\s*\{\(props\.sessionStatusBadge \|\| props\.connectionAlert \|\| props\.eventStreamAlert\) && \(/,
+ /<\/header>\s*\{\/\*[\s\S]*?\*\/\}\s*<div className="maka-chat-status-cluster">/,
  'status badges should render after the header, not inside the header toolbar row',
  );
  assert.match(
  src,
- /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\)\}\s*\{isLocalSimulationBackend && \(/,
+ /<div className="maka-chat-status-cluster">\s*\{props\.sessionStatusBadge && /,
+ 'the cluster div must be unconditionally mounted with badges conditional INSIDE (the :empty transition depends on it)',
+ );
+ assert.match(
+ src,
+ /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\{isLocalSimulationBackend && \(/,
  'status badges should stay before the fake-backend banner so normal flow reserves vertical space before first content',
  );
  });
 
+ it('collapses via :empty with tokenized height/opacity transition instead of unmount', async () => {
+ const css = await readRendererContractCss();
+ const body = ruleBody(css, '.maka-chat-status-cluster');
+ assert.match(body, /interpolate-size:\s*allow-keywords/, 'height auto↔0 transition needs interpolate-size');
+ assert.match(body, /transition:[\s\S]*?height var\(--duration-large\)/, 'height must transition on a duration token');
+ const emptyBody = ruleBody(css, '.maka-chat-status-cluster:empty');
+ assert.match(emptyBody, /height:\s*0/);
+ assert.match(emptyBody, /opacity:\s*0/);
+ });
+
+ it('reserves the footer placeholder for every live turn, not only text answers', async () => {
+ // Three-way review (ChatGPT P2): a settled turn ALWAYS mounts a footer
+ // (deriveTurnFooterActions yields regenerate/branch from TurnStatus alone;
+ // materialize emits a timeline item for a step's thinking even with empty
+ // text), so a thinking-only turn settles WITH a footer. The live footer
+ // placeholder must live inside the `streamingText || thinkingText` section
+ // and render unconditionally there — never re-narrowed to streamingText —
+ // so it reserves the footer box for every live turn.
+ //
+ // Groundwork only: this locks the reserved box. It makes the swap
+ // height-neutral where the live section is held to settle (text turns, via
+ // the draining handshake). The textless / thinking-only completion path is
+ // still non-atomic (clears live before the committed footer mounts); that
+ // is tracked in the single-render-path convergence (#642), not asserted
+ // here.
+ const src = await readRepo('packages/ui/src/chat-view.tsx');
+ assert.match(
+ src,
+ /Unconditional \(not gated on streamingText\)[\s\S]*?\*\/\}\s*<div aria-hidden="true" className="mt-0\.5 h-8" \/>/,
+ 'the footer placeholder must render unconditionally inside the live section (covers thinking-only turns)',
+ );
+ assert.doesNotMatch(
+ src,
+ /\{props\.streamingText && <div aria-hidden="true" className="mt-0\.5 h-8" \/>\}/,
+ 'the placeholder must not be re-gated on streamingText alone — that misses thinking-only settle',
+ );
+ });
+
  it('uses an in-flow wrapping row instead of absolute positioning', async () => {
  const css = await readRendererContractCss();
  const body = ruleBody(css, '.maka-chat-status-cluster');

apps/desktop/src/main/__tests__/design-system-governance-406-contract.test.ts

@@ -111,10 +111,20 @@ describe('issue #406 design-system governance contract', () => {
  'maka-toast-enter',
  'maka-toast-exit',
  'maka-processing-sweep',
- 'maka-cursor',
  'maka-list-row-streaming-pulse',
  'maka-pulse',
- 'maka-reasoning-panel-pulse',
+ // Streaming UI rework: the "深度思考" disclosure title + a working trow's
+ // active-tool summary sweep light across the label (functional "still
+ // working" signal), driven by the TextShimmer primitive. The retired ▎
+ // caret's `maka-cursor` is replaced by `maka-stream-fade-in`, the
+ // per-word entrance that signals freshly streamed text.
+ 'maka-text-shimmer',
+ 'maka-stream-fade-in',
+ // Handoff polish: the turn footer toolbar fades in when a live turn
+ // settles (opacity only, into an equal-height placeholder slot) —
+ // functional "the answer is final, actions are now available" signal,
+ // never applied on history-hydration mounts.
+ 'maka-footer-fade-in',
  'maka-shimmer',
  'maka-status-spin',
  'maka-tool-pulse',

apps/desktop/src/main/__tests__/markdown-prose-contract.test.ts

@@ -198,12 +198,13 @@ describe('PROSE-POLISH-13PX-0 contract (#546 Phase B)', () => {
  && !/\.maka-prose\s*>\s*p:nth-last-child/.test(css),
  'structural :nth-last-child prose hacks must not return — they assume a trailing non-markdown child that no longer exists',
  );
- // The streaming caret still needs the trailing paragraph inlined, but
- // scoped to the streaming bubble only.
- assert.match(
- css,
- /\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/,
- 'the caret-inline rule must be scoped to .maka-bubble-streaming so committed messages and .maka-prose reusers (tool results, #546 PR6) keep block paragraphs',
+ // The streaming ▎ caret (and its trailing-<p> inline hack) was retired by
+ // the streaming UI rework — the "still writing" signal is the per-word
+ // fade-in — so the streaming bubble must NOT re-introduce a
+ // `p:last-child { display: inline }` rule that would collapse block spacing.
+ assert.ok(
+ !/\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/.test(css),
+ 'the retired caret-inline hack must not return — the trailing paragraph keeps normal block layout',
  );
  // Negative side of the same contract: an unscoped variant on the
  // committed-message classes would inline the final paragraph of every

apps/desktop/src/main/__tests__/materialize-turns.test.ts

@@ -347,6 +347,122 @@ describe('materializeTurns', () => {
  });
 });
 
+function toolCallStep(turnId: string, ts: number, id: string, stepId: string, toolName = 'Read'): StoredMessage {
+ return { type: 'tool_call', id, turnId, ts, toolName, args: {}, stepId };
+}
+
+function assistantStep(
+ turnId: string,
+ ts: number,
+ id: string,
+ text: string,
+ thinking?: string,
+): StoredMessage {
+ return {
+ type: 'assistant',
+ id,
+ turnId,
+ ts,
+ text,
+ modelId: 'm',
+ ...(thinking !== undefined ? { thinking: { text: thinking } } : {}),
+ } as StoredMessage;
+}
+
+describe('materializeTurns timeline', () => {
+ it('interleaves each step: thinking -> text -> that step’s tools', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a1', 'step one', 'think one'),
+ toolCallStep('t1', 104, 'c2', 'a2'),
+ toolResultMsg('t1', 105, 'c2'),
+ assistantStep('t1', 106, 'a2', 'step two', 'think two'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['thinking', 'text', 'tools', 'thinking', 'text', 'tools']);
+ assert.equal((timeline[0] as { text: string }).text, 'think one');
+ assert.equal((timeline[1] as { text: string }).text, 'step one');
+ assert.equal((timeline[2] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[5] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c2');
+ // Aggregate fields still reflect the concatenated whole for legacy consumers.
+ assert.equal(turns[0]?.assistant?.text, 'step one\n\nstep two');
+ assert.equal(turns[0]?.assistantThinking, 'think one\n\nthink two');
+ });
+
+ it('renders a pure-tool step’s orphan tools before the next step’s answer', () => {
+ // The most common tool turn: step a1 only calls tools (no assistant row
+ // is persisted for it), step a2 delivers the summary. The a1 tools carry
+ // a stepId no assistant row matches — they must still render before the
+ // answer, not park past it as answer-then-tools.
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a2', 'summary', 'think'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'thinking', 'text']);
+ assert.equal((timeline[0] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[2] as { text: string }).text, 'summary');
+ });
+
+ it('legacy call with no stepId sits before the summary text', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallMsg('t1', 101, 'c1', 'Read'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantMsg('t1', 103, 'summary'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'text']);
+ assert.equal((timeline[1] as { text: string }).text, 'summary');
+ });
+
+ it('flushes leftover tools as a trailing group when the turn has no assistant row (abort)', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools']);
+ assert.equal((timeline[0] as { items: { status: string }[] }).items[0]?.status, 'interrupted');
+ });
+
+ it('appends live-only in-flight tools to the timeline tail', () => {
+ const turns = materializeTurns(
+ [userMsg('t1', 100, 'q'), assistantStep('t1', 103, 'a1', 'hi')],
+ [{ toolUseId: 'live-1', toolName: 'Bash', status: 'running', args: {} }],
+ );
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['text', 'tools']);
+ assert.equal((timeline[1] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'live-1');
+ });
+
+ it('merges adjacent thinking blocks and adjacent tool groups', () => {
+ const thinkingOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ assistantStep('t1', 101, 'a1', '', 'first'),
+ assistantStep('t1', 102, 'a2', '', 'second'),
+ ]);
+ const tl1 = thinkingOnly[0]!.timeline;
+ assert.deepEqual(tl1.map((i) => i.kind), ['thinking']);
+ assert.equal((tl1[0] as { text: string }).text, 'first\n\nsecond');
+
+ const toolsOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ assistantStep('t1', 102, 'a1', ''),
+ toolCallStep('t1', 103, 'c2', 'a2'),
+ assistantStep('t1', 104, 'a2', ''),
+ ]);
+ const tl2 = toolsOnly[0]!.timeline;
+ assert.deepEqual(tl2.map((i) => i.kind), ['tools']);
+ assert.equal((tl2[0] as { items: unknown[] }).items.length, 2);
+ });
+});
+
 describe('deriveTurnLineageMap', () => {
  it('derives reverse links without mutating old turns', () => {
  const map = deriveTurnLineageMap([

apps/desktop/src/main/__tests__/smooth-stream.test.ts

@@ -132,7 +132,14 @@ describe('computeFrameAdvance', () => {
  );
  });
 
- it('returns 0 when dt is non-positive', () => {
+ // Regression lock (streaming UI rework, blank-bubble freeze): rAF timestamps
+ // are vsync-aligned and lag the wall clock under IPC delta bursts, so dtMs
+ // clamps to 0 for every tick in the recovery window. Returning 0 left
+ // displayedCount unchanged → the RAF effect never re-armed → the typewriter
+ // died with a full backlog and the answer snapped in at stream end. With
+ // backlog present, a non-positive dt must still advance 1 to keep the
+ // single-owner RAF chain alive.
+ it('advances 1 (not 0) when dt is non-positive but backlog remains — keeps the RAF chain alive', () => {
  assert.equal(
  computeFrameAdvance({
  rawGraphemeCount: 100,
@@ -142,7 +149,7 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
-0,
+1,
  );
  assert.equal(
  computeFrameAdvance({
@@ -153,6 +160,18 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
+ 1,
+ );
+ // …but never invents work: zero backlog still returns 0.
+ assert.equal(
+ computeFrameAdvance({
+ rawGraphemeCount: 10,
+ displayedGraphemeCount: 10,
+ emaCps: 60,
+ dtMs: 0,
+ minCps: 30,
+ maxCps: 400,
+ }),
  0,
  );
  });

apps/desktop/src/main/__tests__/chat-marker-cascade-contract.test.ts

@@ -40,18 +40,18 @@ describe('chat Marker shell migration contract (#332 PR2)', () => {
  }
  });
 
- it('keeps the turn container + deferred reasoning chrome (out of scope)', async () => {
+ it('keeps the turn container (out of scope)', async () => {
  const css = await readAllRendererCss();
  for (const selector of [
  // The `.maka-turn` flex/measure container is NOT a marker — it stays.
  '.maka-turn {',
- '.maka-turn-tools',
  '.maka-turn-streaming',
  '.maka-turn[data-search-highlight="true"]',
- // `.maka-turn-thinking` is explicitly deferred (pseudo-element chevron +
- // @starting-style fade don't reduce to leaf utilities); it stays authored.
- '.maka-turn-thinking',
- '.maka-turn-thinking [data-slot="collapsible-trigger"]',
+ // NOTE: `.maka-turn-thinking` and `.maka-turn-tools` were retired by the
+ // streaming UI rework — reasoning now renders through the `DeepThinking`
+ // disclosure (Tailwind-literal chrome + the `maka-text-shimmer` primitive)
+ // and tools through the flat `ToolTrow`, so the hand-authored committed-
+ // turn thinking `<details>` chrome and the tools-section wrapper are gone.
  ]) {
  assert.ok(css.includes(selector), `out-of-scope turn rule "${selector}" must be preserved`);
  }

apps/desktop/src/main/__tests__/chat-status-cluster-layout-contract.test.ts

@@ -21,18 +21,66 @@ describe('chat status cluster layout contract', () => {
  it('keeps alert/status badges in flow between the header and first chat content', async () => {
  const src = await readRepo('packages/ui/src/chat-view.tsx');
 
+ // The cluster div is ALWAYS mounted (streaming-settle polish): it
+ // collapses via the CSS `:empty` height transition instead of conditional
+ // mount/unmount, which used to snap the conversation column up by the
+ // badge-row height the frame a run completed. The badges inside stay
+ // conditional.
  assert.match(
  src,
- /<header className="maka-chat-header">[\s\S]*?<\/header>\s*\{\(props\.sessionStatusBadge \|\| props\.connectionAlert \|\| props\.eventStreamAlert\) && \(/,
+ /<\/header>\s*\{\/\*[\s\S]*?\*\/\}\s*<div className="maka-chat-status-cluster">/,
  'status badges should render after the header, not inside the header toolbar row',
  );
  assert.match(
  src,
- /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\)\}\s*\{isLocalSimulationBackend && \(/,
+ /<div className="maka-chat-status-cluster">\s*\{props\.sessionStatusBadge && /,
+ 'the cluster div must be unconditionally mounted with badges conditional INSIDE (the :empty transition depends on it)',
+ );
+ assert.match(
+ src,
+ /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\{isLocalSimulationBackend && \(/,
  'status badges should stay before the fake-backend banner so normal flow reserves vertical space before first content',
  );
  });
 
+ it('collapses via :empty with tokenized height/opacity transition instead of unmount', async () => {
+ const css = await readRendererContractCss();
+ const body = ruleBody(css, '.maka-chat-status-cluster');
+ assert.match(body, /interpolate-size:\s*allow-keywords/, 'height auto↔0 transition needs interpolate-size');
+ assert.match(body, /transition:[\s\S]*?height var\(--duration-large\)/, 'height must transition on a duration token');
+ const emptyBody = ruleBody(css, '.maka-chat-status-cluster:empty');
+ assert.match(emptyBody, /height:\s*0/);
+ assert.match(emptyBody, /opacity:\s*0/);
+ });
+
+ it('reserves the footer placeholder for every live turn, not only text answers', async () => {
+ // Three-way review (ChatGPT P2): a settled turn ALWAYS mounts a footer
+ // (deriveTurnFooterActions yields regenerate/branch from TurnStatus alone;
+ // materialize emits a timeline item for a step's thinking even with empty
+ // text), so a thinking-only turn settles WITH a footer. The live footer
+ // placeholder must live inside the `streamingText || thinkingText` section
+ // and render unconditionally there — never re-narrowed to streamingText —
+ // so it reserves the footer box for every live turn.
+ //
+ // Groundwork only: this locks the reserved box. It makes the swap
+ // height-neutral where the live section is held to settle (text turns, via
+ // the draining handshake). The textless / thinking-only completion path is
+ // still non-atomic (clears live before the committed footer mounts); that
+ // is tracked in the single-render-path convergence (#642), not asserted
+ // here.
+ const src = await readRepo('packages/ui/src/chat-view.tsx');
+ assert.match(
+ src,
+ /Unconditional \(not gated on streamingText\)[\s\S]*?\*\/\}\s*<div aria-hidden="true" className="mt-0\.5 h-8" \/>/,
+ 'the footer placeholder must render unconditionally inside the live section (covers thinking-only turns)',
+ );
+ assert.doesNotMatch(
+ src,
+ /\{props\.streamingText && <div aria-hidden="true" className="mt-0\.5 h-8" \/>\}/,
+ 'the placeholder must not be re-gated on streamingText alone — that misses thinking-only settle',
+ );
+ });
+
  it('uses an in-flow wrapping row instead of absolute positioning', async () => {
  const css = await readRendererContractCss();
  const body = ruleBody(css, '.maka-chat-status-cluster');

apps/desktop/src/main/__tests__/design-system-governance-406-contract.test.ts

@@ -111,10 +111,20 @@ describe('issue #406 design-system governance contract', () => {
  'maka-toast-enter',
  'maka-toast-exit',
  'maka-processing-sweep',
- 'maka-cursor',
  'maka-list-row-streaming-pulse',
  'maka-pulse',
- 'maka-reasoning-panel-pulse',
+ // Streaming UI rework: the "深度思考" disclosure title + a working trow's
+ // active-tool summary sweep light across the label (functional "still
+ // working" signal), driven by the TextShimmer primitive. The retired ▎
+ // caret's `maka-cursor` is replaced by `maka-stream-fade-in`, the
+ // per-word entrance that signals freshly streamed text.
+ 'maka-text-shimmer',
+ 'maka-stream-fade-in',
+ // Handoff polish: the turn footer toolbar fades in when a live turn
+ // settles (opacity only, into an equal-height placeholder slot) —
+ // functional "the answer is final, actions are now available" signal,
+ // never applied on history-hydration mounts.
+ 'maka-footer-fade-in',
  'maka-shimmer',
  'maka-status-spin',
  'maka-tool-pulse',

apps/desktop/src/main/__tests__/markdown-prose-contract.test.ts

@@ -198,12 +198,13 @@ describe('PROSE-POLISH-13PX-0 contract (#546 Phase B)', () => {
  && !/\.maka-prose\s*>\s*p:nth-last-child/.test(css),
  'structural :nth-last-child prose hacks must not return — they assume a trailing non-markdown child that no longer exists',
  );
- // The streaming caret still needs the trailing paragraph inlined, but
- // scoped to the streaming bubble only.
- assert.match(
- css,
- /\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/,
- 'the caret-inline rule must be scoped to .maka-bubble-streaming so committed messages and .maka-prose reusers (tool results, #546 PR6) keep block paragraphs',
+ // The streaming ▎ caret (and its trailing-<p> inline hack) was retired by
+ // the streaming UI rework — the "still writing" signal is the per-word
+ // fade-in — so the streaming bubble must NOT re-introduce a
+ // `p:last-child { display: inline }` rule that would collapse block spacing.
+ assert.ok(
+ !/\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/.test(css),
+ 'the retired caret-inline hack must not return — the trailing paragraph keeps normal block layout',
  );
  // Negative side of the same contract: an unscoped variant on the
  // committed-message classes would inline the final paragraph of every

apps/desktop/src/main/__tests__/materialize-turns.test.ts

@@ -347,6 +347,122 @@ describe('materializeTurns', () => {
  });
 });
 
+function toolCallStep(turnId: string, ts: number, id: string, stepId: string, toolName = 'Read'): StoredMessage {
+ return { type: 'tool_call', id, turnId, ts, toolName, args: {}, stepId };
+}
+
+function assistantStep(
+ turnId: string,
+ ts: number,
+ id: string,
+ text: string,
+ thinking?: string,
+): StoredMessage {
+ return {
+ type: 'assistant',
+ id,
+ turnId,
+ ts,
+ text,
+ modelId: 'm',
+ ...(thinking !== undefined ? { thinking: { text: thinking } } : {}),
+ } as StoredMessage;
+}
+
+describe('materializeTurns timeline', () => {
+ it('interleaves each step: thinking -> text -> that step’s tools', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a1', 'step one', 'think one'),
+ toolCallStep('t1', 104, 'c2', 'a2'),
+ toolResultMsg('t1', 105, 'c2'),
+ assistantStep('t1', 106, 'a2', 'step two', 'think two'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['thinking', 'text', 'tools', 'thinking', 'text', 'tools']);
+ assert.equal((timeline[0] as { text: string }).text, 'think one');
+ assert.equal((timeline[1] as { text: string }).text, 'step one');
+ assert.equal((timeline[2] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[5] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c2');
+ // Aggregate fields still reflect the concatenated whole for legacy consumers.
+ assert.equal(turns[0]?.assistant?.text, 'step one\n\nstep two');
+ assert.equal(turns[0]?.assistantThinking, 'think one\n\nthink two');
+ });
+
+ it('renders a pure-tool step’s orphan tools before the next step’s answer', () => {
+ // The most common tool turn: step a1 only calls tools (no assistant row
+ // is persisted for it), step a2 delivers the summary. The a1 tools carry
+ // a stepId no assistant row matches — they must still render before the
+ // answer, not park past it as answer-then-tools.
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a2', 'summary', 'think'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'thinking', 'text']);
+ assert.equal((timeline[0] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[2] as { text: string }).text, 'summary');
+ });
+
+ it('legacy call with no stepId sits before the summary text', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallMsg('t1', 101, 'c1', 'Read'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantMsg('t1', 103, 'summary'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'text']);
+ assert.equal((timeline[1] as { text: string }).text, 'summary');
+ });
+
+ it('flushes leftover tools as a trailing group when the turn has no assistant row (abort)', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools']);
+ assert.equal((timeline[0] as { items: { status: string }[] }).items[0]?.status, 'interrupted');
+ });
+
+ it('appends live-only in-flight tools to the timeline tail', () => {
+ const turns = materializeTurns(
+ [userMsg('t1', 100, 'q'), assistantStep('t1', 103, 'a1', 'hi')],
+ [{ toolUseId: 'live-1', toolName: 'Bash', status: 'running', args: {} }],
+ );
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['text', 'tools']);
+ assert.equal((timeline[1] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'live-1');
+ });
+
+ it('merges adjacent thinking blocks and adjacent tool groups', () => {
+ const thinkingOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ assistantStep('t1', 101, 'a1', '', 'first'),
+ assistantStep('t1', 102, 'a2', '', 'second'),
+ ]);
+ const tl1 = thinkingOnly[0]!.timeline;
+ assert.deepEqual(tl1.map((i) => i.kind), ['thinking']);
+ assert.equal((tl1[0] as { text: string }).text, 'first\n\nsecond');
+
+ const toolsOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ assistantStep('t1', 102, 'a1', ''),
+ toolCallStep('t1', 103, 'c2', 'a2'),
+ assistantStep('t1', 104, 'a2', ''),
+ ]);
+ const tl2 = toolsOnly[0]!.timeline;
+ assert.deepEqual(tl2.map((i) => i.kind), ['tools']);
+ assert.equal((tl2[0] as { items: unknown[] }).items.length, 2);
+ });
+});
+
 describe('deriveTurnLineageMap', () => {
  it('derives reverse links without mutating old turns', () => {
  const map = deriveTurnLineageMap([

apps/desktop/src/main/__tests__/smooth-stream.test.ts

@@ -132,7 +132,14 @@ describe('computeFrameAdvance', () => {
  );
  });
 
- it('returns 0 when dt is non-positive', () => {
+ // Regression lock (streaming UI rework, blank-bubble freeze): rAF timestamps
+ // are vsync-aligned and lag the wall clock under IPC delta bursts, so dtMs
+ // clamps to 0 for every tick in the recovery window. Returning 0 left
+ // displayedCount unchanged → the RAF effect never re-armed → the typewriter
+ // died with a full backlog and the answer snapped in at stream end. With
+ // backlog present, a non-positive dt must still advance 1 to keep the
+ // single-owner RAF chain alive.
+ it('advances 1 (not 0) when dt is non-positive but backlog remains — keeps the RAF chain alive', () => {
  assert.equal(
  computeFrameAdvance({
  rawGraphemeCount: 100,
@@ -142,7 +149,7 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
-0,
+1,
  );
  assert.equal(
  computeFrameAdvance({
@@ -153,6 +160,18 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
+ 1,
+ );
+ // …but never invents work: zero backlog still returns 0.
+ assert.equal(
+ computeFrameAdvance({
+ rawGraphemeCount: 10,
+ displayedGraphemeCount: 10,
+ emaCps: 60,
+ dtMs: 0,
+ minCps: 30,
+ maxCps: 400,
+ }),
  0,
  );
  });

apps/desktop/src/main/__tests__/chat-marker-cascade-contract.test.ts

@@ -40,18 +40,18 @@ describe('chat Marker shell migration contract (#332 PR2)', () => {
  }
  });
 
- it('keeps the turn container + deferred reasoning chrome (out of scope)', async () => {
+ it('keeps the turn container (out of scope)', async () => {
  const css = await readAllRendererCss();
  for (const selector of [
  // The `.maka-turn` flex/measure container is NOT a marker — it stays.
  '.maka-turn {',
- '.maka-turn-tools',
  '.maka-turn-streaming',
  '.maka-turn[data-search-highlight="true"]',
- // `.maka-turn-thinking` is explicitly deferred (pseudo-element chevron +
- // @starting-style fade don't reduce to leaf utilities); it stays authored.
- '.maka-turn-thinking',
- '.maka-turn-thinking [data-slot="collapsible-trigger"]',
+ // NOTE: `.maka-turn-thinking` and `.maka-turn-tools` were retired by the
+ // streaming UI rework — reasoning now renders through the `DeepThinking`
+ // disclosure (Tailwind-literal chrome + the `maka-text-shimmer` primitive)
+ // and tools through the flat `ToolTrow`, so the hand-authored committed-
+ // turn thinking `<details>` chrome and the tools-section wrapper are gone.
  ]) {
  assert.ok(css.includes(selector), `out-of-scope turn rule "${selector}" must be preserved`);
  }

apps/desktop/src/main/__tests__/chat-status-cluster-layout-contract.test.ts

@@ -21,18 +21,66 @@ describe('chat status cluster layout contract', () => {
  it('keeps alert/status badges in flow between the header and first chat content', async () => {
  const src = await readRepo('packages/ui/src/chat-view.tsx');
 
+ // The cluster div is ALWAYS mounted (streaming-settle polish): it
+ // collapses via the CSS `:empty` height transition instead of conditional
+ // mount/unmount, which used to snap the conversation column up by the
+ // badge-row height the frame a run completed. The badges inside stay
+ // conditional.
  assert.match(
  src,
- /<header className="maka-chat-header">[\s\S]*?<\/header>\s*\{\(props\.sessionStatusBadge \|\| props\.connectionAlert \|\| props\.eventStreamAlert\) && \(/,
+ /<\/header>\s*\{\/\*[\s\S]*?\*\/\}\s*<div className="maka-chat-status-cluster">/,
  'status badges should render after the header, not inside the header toolbar row',
  );
  assert.match(
  src,
- /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\)\}\s*\{isLocalSimulationBackend && \(/,
+ /<div className="maka-chat-status-cluster">\s*\{props\.sessionStatusBadge && /,
+ 'the cluster div must be unconditionally mounted with badges conditional INSIDE (the :empty transition depends on it)',
+ );
+ assert.match(
+ src,
+ /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\{isLocalSimulationBackend && \(/,
  'status badges should stay before the fake-backend banner so normal flow reserves vertical space before first content',
  );
  });
 
+ it('collapses via :empty with tokenized height/opacity transition instead of unmount', async () => {
+ const css = await readRendererContractCss();
+ const body = ruleBody(css, '.maka-chat-status-cluster');
+ assert.match(body, /interpolate-size:\s*allow-keywords/, 'height auto↔0 transition needs interpolate-size');
+ assert.match(body, /transition:[\s\S]*?height var\(--duration-large\)/, 'height must transition on a duration token');
+ const emptyBody = ruleBody(css, '.maka-chat-status-cluster:empty');
+ assert.match(emptyBody, /height:\s*0/);
+ assert.match(emptyBody, /opacity:\s*0/);
+ });
+
+ it('reserves the footer placeholder for every live turn, not only text answers', async () => {
+ // Three-way review (ChatGPT P2): a settled turn ALWAYS mounts a footer
+ // (deriveTurnFooterActions yields regenerate/branch from TurnStatus alone;
+ // materialize emits a timeline item for a step's thinking even with empty
+ // text), so a thinking-only turn settles WITH a footer. The live footer
+ // placeholder must live inside the `streamingText || thinkingText` section
+ // and render unconditionally there — never re-narrowed to streamingText —
+ // so it reserves the footer box for every live turn.
+ //
+ // Groundwork only: this locks the reserved box. It makes the swap
+ // height-neutral where the live section is held to settle (text turns, via
+ // the draining handshake). The textless / thinking-only completion path is
+ // still non-atomic (clears live before the committed footer mounts); that
+ // is tracked in the single-render-path convergence (#642), not asserted
+ // here.
+ const src = await readRepo('packages/ui/src/chat-view.tsx');
+ assert.match(
+ src,
+ /Unconditional \(not gated on streamingText\)[\s\S]*?\*\/\}\s*<div aria-hidden="true" className="mt-0\.5 h-8" \/>/,
+ 'the footer placeholder must render unconditionally inside the live section (covers thinking-only turns)',
+ );
+ assert.doesNotMatch(
+ src,
+ /\{props\.streamingText && <div aria-hidden="true" className="mt-0\.5 h-8" \/>\}/,
+ 'the placeholder must not be re-gated on streamingText alone — that misses thinking-only settle',
+ );
+ });
+
  it('uses an in-flow wrapping row instead of absolute positioning', async () => {
  const css = await readRendererContractCss();
  const body = ruleBody(css, '.maka-chat-status-cluster');

apps/desktop/src/main/__tests__/design-system-governance-406-contract.test.ts

@@ -111,10 +111,20 @@ describe('issue #406 design-system governance contract', () => {
  'maka-toast-enter',
  'maka-toast-exit',
  'maka-processing-sweep',
- 'maka-cursor',
  'maka-list-row-streaming-pulse',
  'maka-pulse',
- 'maka-reasoning-panel-pulse',
+ // Streaming UI rework: the "深度思考" disclosure title + a working trow's
+ // active-tool summary sweep light across the label (functional "still
+ // working" signal), driven by the TextShimmer primitive. The retired ▎
+ // caret's `maka-cursor` is replaced by `maka-stream-fade-in`, the
+ // per-word entrance that signals freshly streamed text.
+ 'maka-text-shimmer',
+ 'maka-stream-fade-in',
+ // Handoff polish: the turn footer toolbar fades in when a live turn
+ // settles (opacity only, into an equal-height placeholder slot) —
+ // functional "the answer is final, actions are now available" signal,
+ // never applied on history-hydration mounts.
+ 'maka-footer-fade-in',
  'maka-shimmer',
  'maka-status-spin',
  'maka-tool-pulse',

apps/desktop/src/main/__tests__/markdown-prose-contract.test.ts

@@ -198,12 +198,13 @@ describe('PROSE-POLISH-13PX-0 contract (#546 Phase B)', () => {
  && !/\.maka-prose\s*>\s*p:nth-last-child/.test(css),
  'structural :nth-last-child prose hacks must not return — they assume a trailing non-markdown child that no longer exists',
  );
- // The streaming caret still needs the trailing paragraph inlined, but
- // scoped to the streaming bubble only.
- assert.match(
- css,
- /\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/,
- 'the caret-inline rule must be scoped to .maka-bubble-streaming so committed messages and .maka-prose reusers (tool results, #546 PR6) keep block paragraphs',
+ // The streaming ▎ caret (and its trailing-<p> inline hack) was retired by
+ // the streaming UI rework — the "still writing" signal is the per-word
+ // fade-in — so the streaming bubble must NOT re-introduce a
+ // `p:last-child { display: inline }` rule that would collapse block spacing.
+ assert.ok(
+ !/\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/.test(css),
+ 'the retired caret-inline hack must not return — the trailing paragraph keeps normal block layout',
  );
  // Negative side of the same contract: an unscoped variant on the
  // committed-message classes would inline the final paragraph of every

apps/desktop/src/main/__tests__/materialize-turns.test.ts

@@ -347,6 +347,122 @@ describe('materializeTurns', () => {
  });
 });
 
+function toolCallStep(turnId: string, ts: number, id: string, stepId: string, toolName = 'Read'): StoredMessage {
+ return { type: 'tool_call', id, turnId, ts, toolName, args: {}, stepId };
+}
+
+function assistantStep(
+ turnId: string,
+ ts: number,
+ id: string,
+ text: string,
+ thinking?: string,
+): StoredMessage {
+ return {
+ type: 'assistant',
+ id,
+ turnId,
+ ts,
+ text,
+ modelId: 'm',
+ ...(thinking !== undefined ? { thinking: { text: thinking } } : {}),
+ } as StoredMessage;
+}
+
+describe('materializeTurns timeline', () => {
+ it('interleaves each step: thinking -> text -> that step’s tools', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a1', 'step one', 'think one'),
+ toolCallStep('t1', 104, 'c2', 'a2'),
+ toolResultMsg('t1', 105, 'c2'),
+ assistantStep('t1', 106, 'a2', 'step two', 'think two'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['thinking', 'text', 'tools', 'thinking', 'text', 'tools']);
+ assert.equal((timeline[0] as { text: string }).text, 'think one');
+ assert.equal((timeline[1] as { text: string }).text, 'step one');
+ assert.equal((timeline[2] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[5] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c2');
+ // Aggregate fields still reflect the concatenated whole for legacy consumers.
+ assert.equal(turns[0]?.assistant?.text, 'step one\n\nstep two');
+ assert.equal(turns[0]?.assistantThinking, 'think one\n\nthink two');
+ });
+
+ it('renders a pure-tool step’s orphan tools before the next step’s answer', () => {
+ // The most common tool turn: step a1 only calls tools (no assistant row
+ // is persisted for it), step a2 delivers the summary. The a1 tools carry
+ // a stepId no assistant row matches — they must still render before the
+ // answer, not park past it as answer-then-tools.
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a2', 'summary', 'think'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'thinking', 'text']);
+ assert.equal((timeline[0] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[2] as { text: string }).text, 'summary');
+ });
+
+ it('legacy call with no stepId sits before the summary text', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallMsg('t1', 101, 'c1', 'Read'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantMsg('t1', 103, 'summary'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'text']);
+ assert.equal((timeline[1] as { text: string }).text, 'summary');
+ });
+
+ it('flushes leftover tools as a trailing group when the turn has no assistant row (abort)', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools']);
+ assert.equal((timeline[0] as { items: { status: string }[] }).items[0]?.status, 'interrupted');
+ });
+
+ it('appends live-only in-flight tools to the timeline tail', () => {
+ const turns = materializeTurns(
+ [userMsg('t1', 100, 'q'), assistantStep('t1', 103, 'a1', 'hi')],
+ [{ toolUseId: 'live-1', toolName: 'Bash', status: 'running', args: {} }],
+ );
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['text', 'tools']);
+ assert.equal((timeline[1] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'live-1');
+ });
+
+ it('merges adjacent thinking blocks and adjacent tool groups', () => {
+ const thinkingOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ assistantStep('t1', 101, 'a1', '', 'first'),
+ assistantStep('t1', 102, 'a2', '', 'second'),
+ ]);
+ const tl1 = thinkingOnly[0]!.timeline;
+ assert.deepEqual(tl1.map((i) => i.kind), ['thinking']);
+ assert.equal((tl1[0] as { text: string }).text, 'first\n\nsecond');
+
+ const toolsOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ assistantStep('t1', 102, 'a1', ''),
+ toolCallStep('t1', 103, 'c2', 'a2'),
+ assistantStep('t1', 104, 'a2', ''),
+ ]);
+ const tl2 = toolsOnly[0]!.timeline;
+ assert.deepEqual(tl2.map((i) => i.kind), ['tools']);
+ assert.equal((tl2[0] as { items: unknown[] }).items.length, 2);
+ });
+});
+
 describe('deriveTurnLineageMap', () => {
  it('derives reverse links without mutating old turns', () => {
  const map = deriveTurnLineageMap([

apps/desktop/src/main/__tests__/smooth-stream.test.ts

@@ -132,7 +132,14 @@ describe('computeFrameAdvance', () => {
  );
  });
 
- it('returns 0 when dt is non-positive', () => {
+ // Regression lock (streaming UI rework, blank-bubble freeze): rAF timestamps
+ // are vsync-aligned and lag the wall clock under IPC delta bursts, so dtMs
+ // clamps to 0 for every tick in the recovery window. Returning 0 left
+ // displayedCount unchanged → the RAF effect never re-armed → the typewriter
+ // died with a full backlog and the answer snapped in at stream end. With
+ // backlog present, a non-positive dt must still advance 1 to keep the
+ // single-owner RAF chain alive.
+ it('advances 1 (not 0) when dt is non-positive but backlog remains — keeps the RAF chain alive', () => {
  assert.equal(
  computeFrameAdvance({
  rawGraphemeCount: 100,
@@ -142,7 +149,7 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
-0,
+1,
  );
  assert.equal(
  computeFrameAdvance({
@@ -153,6 +160,18 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
+ 1,
+ );
+ // …but never invents work: zero backlog still returns 0.
+ assert.equal(
+ computeFrameAdvance({
+ rawGraphemeCount: 10,
+ displayedGraphemeCount: 10,
+ emaCps: 60,
+ dtMs: 0,
+ minCps: 30,
+ maxCps: 400,
+ }),
  0,
  );
  });

apps/desktop/src/main/__tests__/chat-marker-cascade-contract.test.ts

@@ -40,18 +40,18 @@ describe('chat Marker shell migration contract (#332 PR2)', () => {
  }
  });
 
- it('keeps the turn container + deferred reasoning chrome (out of scope)', async () => {
+ it('keeps the turn container (out of scope)', async () => {
  const css = await readAllRendererCss();
  for (const selector of [
  // The `.maka-turn` flex/measure container is NOT a marker — it stays.
  '.maka-turn {',
- '.maka-turn-tools',
  '.maka-turn-streaming',
  '.maka-turn[data-search-highlight="true"]',
- // `.maka-turn-thinking` is explicitly deferred (pseudo-element chevron +
- // @starting-style fade don't reduce to leaf utilities); it stays authored.
- '.maka-turn-thinking',
- '.maka-turn-thinking [data-slot="collapsible-trigger"]',
+ // NOTE: `.maka-turn-thinking` and `.maka-turn-tools` were retired by the
+ // streaming UI rework — reasoning now renders through the `DeepThinking`
+ // disclosure (Tailwind-literal chrome + the `maka-text-shimmer` primitive)
+ // and tools through the flat `ToolTrow`, so the hand-authored committed-
+ // turn thinking `<details>` chrome and the tools-section wrapper are gone.
  ]) {
  assert.ok(css.includes(selector), `out-of-scope turn rule "${selector}" must be preserved`);
  }

apps/desktop/src/main/__tests__/chat-status-cluster-layout-contract.test.ts

@@ -21,18 +21,66 @@ describe('chat status cluster layout contract', () => {
  it('keeps alert/status badges in flow between the header and first chat content', async () => {
  const src = await readRepo('packages/ui/src/chat-view.tsx');
 
+ // The cluster div is ALWAYS mounted (streaming-settle polish): it
+ // collapses via the CSS `:empty` height transition instead of conditional
+ // mount/unmount, which used to snap the conversation column up by the
+ // badge-row height the frame a run completed. The badges inside stay
+ // conditional.
  assert.match(
  src,
- /<header className="maka-chat-header">[\s\S]*?<\/header>\s*\{\(props\.sessionStatusBadge \|\| props\.connectionAlert \|\| props\.eventStreamAlert\) && \(/,
+ /<\/header>\s*\{\/\*[\s\S]*?\*\/\}\s*<div className="maka-chat-status-cluster">/,
  'status badges should render after the header, not inside the header toolbar row',
  );
  assert.match(
  src,
- /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\)\}\s*\{isLocalSimulationBackend && \(/,
+ /<div className="maka-chat-status-cluster">\s*\{props\.sessionStatusBadge && /,
+ 'the cluster div must be unconditionally mounted with badges conditional INSIDE (the :empty transition depends on it)',
+ );
+ assert.match(
+ src,
+ /<div className="maka-chat-status-cluster">[\s\S]*?<\/div>\s*\{isLocalSimulationBackend && \(/,
  'status badges should stay before the fake-backend banner so normal flow reserves vertical space before first content',
  );
  });
 
+ it('collapses via :empty with tokenized height/opacity transition instead of unmount', async () => {
+ const css = await readRendererContractCss();
+ const body = ruleBody(css, '.maka-chat-status-cluster');
+ assert.match(body, /interpolate-size:\s*allow-keywords/, 'height auto↔0 transition needs interpolate-size');
+ assert.match(body, /transition:[\s\S]*?height var\(--duration-large\)/, 'height must transition on a duration token');
+ const emptyBody = ruleBody(css, '.maka-chat-status-cluster:empty');
+ assert.match(emptyBody, /height:\s*0/);
+ assert.match(emptyBody, /opacity:\s*0/);
+ });
+
+ it('reserves the footer placeholder for every live turn, not only text answers', async () => {
+ // Three-way review (ChatGPT P2): a settled turn ALWAYS mounts a footer
+ // (deriveTurnFooterActions yields regenerate/branch from TurnStatus alone;
+ // materialize emits a timeline item for a step's thinking even with empty
+ // text), so a thinking-only turn settles WITH a footer. The live footer
+ // placeholder must live inside the `streamingText || thinkingText` section
+ // and render unconditionally there — never re-narrowed to streamingText —
+ // so it reserves the footer box for every live turn.
+ //
+ // Groundwork only: this locks the reserved box. It makes the swap
+ // height-neutral where the live section is held to settle (text turns, via
+ // the draining handshake). The textless / thinking-only completion path is
+ // still non-atomic (clears live before the committed footer mounts); that
+ // is tracked in the single-render-path convergence (#642), not asserted
+ // here.
+ const src = await readRepo('packages/ui/src/chat-view.tsx');
+ assert.match(
+ src,
+ /Unconditional \(not gated on streamingText\)[\s\S]*?\*\/\}\s*<div aria-hidden="true" className="mt-0\.5 h-8" \/>/,
+ 'the footer placeholder must render unconditionally inside the live section (covers thinking-only turns)',
+ );
+ assert.doesNotMatch(
+ src,
+ /\{props\.streamingText && <div aria-hidden="true" className="mt-0\.5 h-8" \/>\}/,
+ 'the placeholder must not be re-gated on streamingText alone — that misses thinking-only settle',
+ );
+ });
+
  it('uses an in-flow wrapping row instead of absolute positioning', async () => {
  const css = await readRendererContractCss();
  const body = ruleBody(css, '.maka-chat-status-cluster');

apps/desktop/src/main/__tests__/design-system-governance-406-contract.test.ts

@@ -111,10 +111,20 @@ describe('issue #406 design-system governance contract', () => {
  'maka-toast-enter',
  'maka-toast-exit',
  'maka-processing-sweep',
- 'maka-cursor',
  'maka-list-row-streaming-pulse',
  'maka-pulse',
- 'maka-reasoning-panel-pulse',
+ // Streaming UI rework: the "深度思考" disclosure title + a working trow's
+ // active-tool summary sweep light across the label (functional "still
+ // working" signal), driven by the TextShimmer primitive. The retired ▎
+ // caret's `maka-cursor` is replaced by `maka-stream-fade-in`, the
+ // per-word entrance that signals freshly streamed text.
+ 'maka-text-shimmer',
+ 'maka-stream-fade-in',
+ // Handoff polish: the turn footer toolbar fades in when a live turn
+ // settles (opacity only, into an equal-height placeholder slot) —
+ // functional "the answer is final, actions are now available" signal,
+ // never applied on history-hydration mounts.
+ 'maka-footer-fade-in',
  'maka-shimmer',
  'maka-status-spin',
  'maka-tool-pulse',

apps/desktop/src/main/__tests__/markdown-prose-contract.test.ts

@@ -198,12 +198,13 @@ describe('PROSE-POLISH-13PX-0 contract (#546 Phase B)', () => {
  && !/\.maka-prose\s*>\s*p:nth-last-child/.test(css),
  'structural :nth-last-child prose hacks must not return — they assume a trailing non-markdown child that no longer exists',
  );
- // The streaming caret still needs the trailing paragraph inlined, but
- // scoped to the streaming bubble only.
- assert.match(
- css,
- /\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/,
- 'the caret-inline rule must be scoped to .maka-bubble-streaming so committed messages and .maka-prose reusers (tool results, #546 PR6) keep block paragraphs',
+ // The streaming ▎ caret (and its trailing-<p> inline hack) was retired by
+ // the streaming UI rework — the "still writing" signal is the per-word
+ // fade-in — so the streaming bubble must NOT re-introduce a
+ // `p:last-child { display: inline }` rule that would collapse block spacing.
+ assert.ok(
+ !/\.maka-bubble-streaming\s*>\s*p:last-child\s*\{[^}]*display:\s*inline/.test(css),
+ 'the retired caret-inline hack must not return — the trailing paragraph keeps normal block layout',
  );
  // Negative side of the same contract: an unscoped variant on the
  // committed-message classes would inline the final paragraph of every

apps/desktop/src/main/__tests__/materialize-turns.test.ts

@@ -347,6 +347,122 @@ describe('materializeTurns', () => {
  });
 });
 
+function toolCallStep(turnId: string, ts: number, id: string, stepId: string, toolName = 'Read'): StoredMessage {
+ return { type: 'tool_call', id, turnId, ts, toolName, args: {}, stepId };
+}
+
+function assistantStep(
+ turnId: string,
+ ts: number,
+ id: string,
+ text: string,
+ thinking?: string,
+): StoredMessage {
+ return {
+ type: 'assistant',
+ id,
+ turnId,
+ ts,
+ text,
+ modelId: 'm',
+ ...(thinking !== undefined ? { thinking: { text: thinking } } : {}),
+ } as StoredMessage;
+}
+
+describe('materializeTurns timeline', () => {
+ it('interleaves each step: thinking -> text -> that step’s tools', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a1', 'step one', 'think one'),
+ toolCallStep('t1', 104, 'c2', 'a2'),
+ toolResultMsg('t1', 105, 'c2'),
+ assistantStep('t1', 106, 'a2', 'step two', 'think two'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['thinking', 'text', 'tools', 'thinking', 'text', 'tools']);
+ assert.equal((timeline[0] as { text: string }).text, 'think one');
+ assert.equal((timeline[1] as { text: string }).text, 'step one');
+ assert.equal((timeline[2] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[5] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c2');
+ // Aggregate fields still reflect the concatenated whole for legacy consumers.
+ assert.equal(turns[0]?.assistant?.text, 'step one\n\nstep two');
+ assert.equal(turns[0]?.assistantThinking, 'think one\n\nthink two');
+ });
+
+ it('renders a pure-tool step’s orphan tools before the next step’s answer', () => {
+ // The most common tool turn: step a1 only calls tools (no assistant row
+ // is persisted for it), step a2 delivers the summary. The a1 tools carry
+ // a stepId no assistant row matches — they must still render before the
+ // answer, not park past it as answer-then-tools.
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantStep('t1', 103, 'a2', 'summary', 'think'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'thinking', 'text']);
+ assert.equal((timeline[0] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'c1');
+ assert.equal((timeline[2] as { text: string }).text, 'summary');
+ });
+
+ it('legacy call with no stepId sits before the summary text', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallMsg('t1', 101, 'c1', 'Read'),
+ toolResultMsg('t1', 102, 'c1'),
+ assistantMsg('t1', 103, 'summary'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools', 'text']);
+ assert.equal((timeline[1] as { text: string }).text, 'summary');
+ });
+
+ it('flushes leftover tools as a trailing group when the turn has no assistant row (abort)', () => {
+ const turns = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ ]);
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['tools']);
+ assert.equal((timeline[0] as { items: { status: string }[] }).items[0]?.status, 'interrupted');
+ });
+
+ it('appends live-only in-flight tools to the timeline tail', () => {
+ const turns = materializeTurns(
+ [userMsg('t1', 100, 'q'), assistantStep('t1', 103, 'a1', 'hi')],
+ [{ toolUseId: 'live-1', toolName: 'Bash', status: 'running', args: {} }],
+ );
+ const timeline = turns[0]!.timeline;
+ assert.deepEqual(timeline.map((i) => i.kind), ['text', 'tools']);
+ assert.equal((timeline[1] as { items: { toolUseId: string }[] }).items[0]?.toolUseId, 'live-1');
+ });
+
+ it('merges adjacent thinking blocks and adjacent tool groups', () => {
+ const thinkingOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ assistantStep('t1', 101, 'a1', '', 'first'),
+ assistantStep('t1', 102, 'a2', '', 'second'),
+ ]);
+ const tl1 = thinkingOnly[0]!.timeline;
+ assert.deepEqual(tl1.map((i) => i.kind), ['thinking']);
+ assert.equal((tl1[0] as { text: string }).text, 'first\n\nsecond');
+
+ const toolsOnly = materializeTurns([
+ userMsg('t1', 100, 'q'),
+ toolCallStep('t1', 101, 'c1', 'a1'),
+ assistantStep('t1', 102, 'a1', ''),
+ toolCallStep('t1', 103, 'c2', 'a2'),
+ assistantStep('t1', 104, 'a2', ''),
+ ]);
+ const tl2 = toolsOnly[0]!.timeline;
+ assert.deepEqual(tl2.map((i) => i.kind), ['tools']);
+ assert.equal((tl2[0] as { items: unknown[] }).items.length, 2);
+ });
+});
+
 describe('deriveTurnLineageMap', () => {
  it('derives reverse links without mutating old turns', () => {
  const map = deriveTurnLineageMap([

apps/desktop/src/main/__tests__/smooth-stream.test.ts

@@ -132,7 +132,14 @@ describe('computeFrameAdvance', () => {
  );
  });
 
- it('returns 0 when dt is non-positive', () => {
+ // Regression lock (streaming UI rework, blank-bubble freeze): rAF timestamps
+ // are vsync-aligned and lag the wall clock under IPC delta bursts, so dtMs
+ // clamps to 0 for every tick in the recovery window. Returning 0 left
+ // displayedCount unchanged → the RAF effect never re-armed → the typewriter
+ // died with a full backlog and the answer snapped in at stream end. With
+ // backlog present, a non-positive dt must still advance 1 to keep the
+ // single-owner RAF chain alive.
+ it('advances 1 (not 0) when dt is non-positive but backlog remains — keeps the RAF chain alive', () => {
  assert.equal(
  computeFrameAdvance({
  rawGraphemeCount: 100,
@@ -142,7 +149,7 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
-0,
+1,
  );
  assert.equal(
  computeFrameAdvance({
@@ -153,6 +160,18 @@ describe('computeFrameAdvance', () => {
  minCps: 30,
  maxCps: 400,
  }),
+ 1,
+ );
+ // …but never invents work: zero backlog still returns 0.
+ assert.equal(
+ computeFrameAdvance({
+ rawGraphemeCount: 10,
+ displayedGraphemeCount: 10,
+ emaCps: 60,
+ dtMs: 0,
+ minCps: 30,
+ maxCps: 400,
+ }),
  0,
  );
  });