From 219043e6bf724d6cb5853b9439b6b6677ea4b3dd Mon Sep 17 00:00:00 2001
From: qer <wbxl2000@outlook.com>
Date: Tue, 23 Jun 2026 13:42:34 +0800
Subject: [PATCH 1/3] refactor(web): extract pure turn-rendering helpers from
 ChatPane

---
 apps/kimi-web/src/components/ChatPane.vue     | 147 ++----------------
 .../src/components/chatTurnRendering.ts       | 139 +++++++++++++++++
 2 files changed, 151 insertions(+), 135 deletions(-)
 create mode 100644 apps/kimi-web/src/components/chatTurnRendering.ts

diff --git a/apps/kimi-web/src/components/ChatPane.vue b/apps/kimi-web/src/components/ChatPane.vue
index 898776e3b1..bd0cc5c14a 100644
--- a/apps/kimi-web/src/components/ChatPane.vue
+++ b/apps/kimi-web/src/components/ChatPane.vue
@@ -2,7 +2,7 @@
 <script setup lang="ts">
 import { computed, nextTick, onMounted, onUnmounted, ref, watch } from 'vue';
 import { useI18n } from 'vue-i18n';
-import type { ChatTurn, ApprovalBlock, FilePreviewRequest, ToolMedia, TurnBlock } from '../types';
+import type { ChatTurn, ApprovalBlock, FilePreviewRequest, ToolMedia } from '../types';
 import ToolCall from './ToolCall.vue';
 import Markdown from './Markdown.vue';
 import ThinkingBlock from './ThinkingBlock.vue';
@@ -11,6 +11,17 @@ import AgentCard from './AgentCard.vue';
 import AgentGroup from './AgentGroup.vue';
 import MoonSpinner from './MoonSpinner.vue';
 import { formatMessageTime } from '../lib/formatMessageTime';
+import {
+  assistantRenderBlocks,
+  formatDuration,
+  formatTokens,
+  renderBlockKey,
+  toolStackKey,
+  toolStackPosition,
+  turnBlocks,
+  turnFinalText,
+  turnToMarkdown,
+} from './chatTurnRendering';
 
 const { t } = useI18n();
 
@@ -211,20 +222,6 @@ function canEditTurn(turn: ChatTurn): boolean {
   );
 }
 
-function formatTokens(n: number): string {
-  if (n >= 1_000_000) return `${(n / 1_000_000).toFixed(1)}M`;
-  if (n >= 1000) return `${(n / 1000).toFixed(1)}k`;
-  return String(n);
-}
-
-function formatDuration(ms: number): string {
-  if (ms < 1000) return `${ms}ms`;
-  if (ms < 60_000) return `${(ms / 1000).toFixed(1)}s`;
-  const m = Math.floor(ms / 60_000);
-  const s = ((ms % 60_000) / 1000).toFixed(1);
-  return `${m}m${s}s`;
-}
-
 /** Divider label: "Context compacted"/"auto-compacted" + optional token stats. */
 function compactionDividerLabel(turn: ChatTurn): string {
   const c = turn.compaction;
@@ -286,32 +283,6 @@ function confirmEditMessage(turn: ChatTurn): void {
 const copiedConversation = ref(false);
 let copiedConversationTimer: ReturnType<typeof setTimeout> | null = null;
 
-function turnFinalText(turn: ChatTurn): string {
-  return turnBlocks(turn)
-    .flatMap((blk) => (blk.kind === 'text' && blk.text ? [blk.text] : []))
-    .join('\n\n');
-}
-
-/** Convert a single turn to Markdown. */
-function turnToMarkdown(turn: ChatTurn): string {
-  const parts: string[] = [];
-  for (const blk of turnBlocks(turn)) {
-    if (blk.kind === 'thinking' && blk.thinking) {
-      parts.push(`> **Thinking**\n> ${blk.thinking.split('\n').join('\n> ')}`);
-    } else if (blk.kind === 'text' && blk.text) {
-      parts.push(blk.text);
-    } else if (blk.kind === 'tool' && blk.tool.output && blk.tool.output.length > 0) {
-      const output = blk.tool.output.join('\n');
-      parts.push(`\`\`\`\n[${blk.tool.name}]\n${output}\n\`\`\``);
-    } else if (blk.kind === 'agent') {
-      parts.push(`**Agent** ${blk.member.name} (${blk.member.phase})`);
-    } else if (blk.kind === 'agentGroup') {
-      parts.push(`**Agents**\n\n${blk.members.map((member) => `- ${member.name}: ${member.phase}`).join('\n')}`);
-    }
-  }
-  return parts.join('\n\n');
-}
-
 /** Convert the entire conversation to Markdown and copy to clipboard. */
 function copyConversation(): void {
   if (props.turns.length === 0) return;
@@ -401,105 +372,11 @@ function copyAssistantRun(index: number): void {
   }).catch(() => {/* ignore */});
 }
 
-// Ordered render blocks for an assistant turn. messagesToTurns supplies `blocks`
-// (thinking + text + tool cards in call order); fall back to deriving them from
-// the aggregate fields for any turn built without blocks (e.g. unit tests).
-function turnBlocks(turn: ChatTurn): TurnBlock[] {
-  if (turn.blocks) return turn.blocks;
-  const blocks: TurnBlock[] = [];
-  if (turn.thinking) blocks.push({ kind: 'thinking', thinking: turn.thinking });
-  if (turn.text) blocks.push({ kind: 'text', text: turn.text });
-  for (const tool of turn.tools ?? []) blocks.push({ kind: 'tool', tool });
-  return blocks;
-}
-
-type ToolStackPosition = 'single' | 'first' | 'middle' | 'last';
-
-type ToolStackItem = {
-  tool: Extract<TurnBlock, { kind: 'tool' }>['tool'];
-  sourceIndex: number;
-};
-
-type AssistantRenderBlock =
-  | { kind: 'thinking'; thinking: string; sourceIndex: number }
-  | { kind: 'text'; text: string; sourceIndex: number }
-  | { kind: 'tool'; tool: ToolStackItem['tool']; sourceIndex: number }
-  | { kind: 'tool-stack'; tools: ToolStackItem[] }
-  | { kind: 'agent'; member: Extract<TurnBlock, { kind: 'agent' }>['member']; sourceIndex: number }
-  | { kind: 'agentGroup'; members: Extract<TurnBlock, { kind: 'agentGroup' }>['members']; sourceIndex: number };
-
-function rendersToolCard(block: Extract<TurnBlock, { kind: 'tool' }>): boolean {
-  return !(block.tool.status === 'ok' && block.tool.media);
-}
-
-function toolStackPosition(index: number, count: number): ToolStackPosition {
-  if (count <= 1) return 'single';
-  if (index === 0) return 'first';
-  if (index === count - 1) return 'last';
-  return 'middle';
-}
-
-function assistantRenderBlocks(turn: ChatTurn): AssistantRenderBlock[] {
-  const blocks = turnBlocks(turn);
-  const rendered: AssistantRenderBlock[] = [];
-  let toolRun: ToolStackItem[] = [];
-
-  const flushToolRun = () => {
-    if (toolRun.length === 1) {
-      const [item] = toolRun;
-      if (item) rendered.push({ kind: 'tool', tool: item.tool, sourceIndex: item.sourceIndex });
-    } else if (toolRun.length > 1) {
-      rendered.push({ kind: 'tool-stack', tools: toolRun });
-    }
-    toolRun = [];
-  };
-
-  blocks.forEach((block, sourceIndex) => {
-    if (block.kind === 'tool') {
-      if (rendersToolCard(block)) {
-        toolRun.push({ tool: block.tool, sourceIndex });
-        return;
-      }
-      flushToolRun();
-      rendered.push({ kind: 'tool', tool: block.tool, sourceIndex });
-      return;
-    }
-
-    flushToolRun();
-    if (block.kind === 'thinking') {
-      rendered.push({ kind: 'thinking', thinking: block.thinking, sourceIndex });
-    } else if (block.kind === 'text') {
-      rendered.push({ kind: 'text', text: block.text, sourceIndex });
-    } else if (block.kind === 'agent') {
-      rendered.push({ kind: 'agent', member: block.member, sourceIndex });
-    } else {
-      rendered.push({ kind: 'agentGroup', members: block.members, sourceIndex });
-    }
-  });
-
-  flushToolRun();
-  return rendered;
-}
-
 function isStreamingRenderBlock(turn: ChatTurn, block: { sourceIndex: number }): boolean {
   if (turn.id !== streamingTurnId.value) return false;
   return block.sourceIndex === turnBlocks(turn).length - 1;
 }
 
-function toolStackKey(item: ToolStackItem): string {
-  return item.tool.id || `tool-${item.sourceIndex}`;
-}
-
-function renderBlockKey(block: AssistantRenderBlock, index: number): string {
-  if (block.kind === 'tool-stack') {
-    return `tool-stack-${block.tools[0]?.sourceIndex ?? index}`;
-  }
-  if (block.kind === 'tool') return toolStackKey({ tool: block.tool, sourceIndex: block.sourceIndex });
-  if (block.kind === 'agent') return `agent-${block.member.id}-${block.sourceIndex}`;
-  if (block.kind === 'agentGroup') return `agent-group-${block.members[0]?.id ?? block.sourceIndex}`;
-  return `${block.kind}-${block.sourceIndex}`;
-}
-
 // NOTE: the turn-summary line ("已调用 N 个工具…") was removed in f9417af. If it
 // comes back, rebuild it from turnBlocks() with i18n strings — the old
 // implementation lives in git history at f9417af^.
diff --git a/apps/kimi-web/src/components/chatTurnRendering.ts b/apps/kimi-web/src/components/chatTurnRendering.ts
new file mode 100644
index 0000000000..7f704eec66
--- /dev/null
+++ b/apps/kimi-web/src/components/chatTurnRendering.ts
@@ -0,0 +1,139 @@
+// apps/kimi-web/src/components/chatTurnRendering.ts
+// Pure turn-rendering helpers: pure functions of their arguments (no Vue
+// reactivity, no component state). Shared by ChatPane.vue's template and its
+// stateful copy/edit helpers.
+import type { ChatTurn, TurnBlock } from '../types';
+
+export function formatTokens(n: number): string {
+  if (n >= 1_000_000) return `${(n / 1_000_000).toFixed(1)}M`;
+  if (n >= 1000) return `${(n / 1000).toFixed(1)}k`;
+  return String(n);
+}
+
+export function formatDuration(ms: number): string {
+  if (ms < 1000) return `${ms}ms`;
+  if (ms < 60_000) return `${(ms / 1000).toFixed(1)}s`;
+  const m = Math.floor(ms / 60_000);
+  const s = ((ms % 60_000) / 1000).toFixed(1);
+  return `${m}m${s}s`;
+}
+
+// Ordered render blocks for an assistant turn. messagesToTurns supplies `blocks`
+// (thinking + text + tool cards in call order); fall back to deriving them from
+// the aggregate fields for any turn built without blocks (e.g. unit tests).
+export function turnBlocks(turn: ChatTurn): TurnBlock[] {
+  if (turn.blocks) return turn.blocks;
+  const blocks: TurnBlock[] = [];
+  if (turn.thinking) blocks.push({ kind: 'thinking', thinking: turn.thinking });
+  if (turn.text) blocks.push({ kind: 'text', text: turn.text });
+  for (const tool of turn.tools ?? []) blocks.push({ kind: 'tool', tool });
+  return blocks;
+}
+
+export type ToolStackPosition = 'single' | 'first' | 'middle' | 'last';
+
+export type ToolStackItem = {
+  tool: Extract<TurnBlock, { kind: 'tool' }>['tool'];
+  sourceIndex: number;
+};
+
+export type AssistantRenderBlock =
+  | { kind: 'thinking'; thinking: string; sourceIndex: number }
+  | { kind: 'text'; text: string; sourceIndex: number }
+  | { kind: 'tool'; tool: ToolStackItem['tool']; sourceIndex: number }
+  | { kind: 'tool-stack'; tools: ToolStackItem[] }
+  | { kind: 'agent'; member: Extract<TurnBlock, { kind: 'agent' }>['member']; sourceIndex: number }
+  | { kind: 'agentGroup'; members: Extract<TurnBlock, { kind: 'agentGroup' }>['members']; sourceIndex: number };
+
+export function rendersToolCard(block: Extract<TurnBlock, { kind: 'tool' }>): boolean {
+  return !(block.tool.status === 'ok' && block.tool.media);
+}
+
+export function toolStackPosition(index: number, count: number): ToolStackPosition {
+  if (count <= 1) return 'single';
+  if (index === 0) return 'first';
+  if (index === count - 1) return 'last';
+  return 'middle';
+}
+
+export function assistantRenderBlocks(turn: ChatTurn): AssistantRenderBlock[] {
+  const blocks = turnBlocks(turn);
+  const rendered: AssistantRenderBlock[] = [];
+  let toolRun: ToolStackItem[] = [];
+
+  const flushToolRun = () => {
+    if (toolRun.length === 1) {
+      const [item] = toolRun;
+      if (item) rendered.push({ kind: 'tool', tool: item.tool, sourceIndex: item.sourceIndex });
+    } else if (toolRun.length > 1) {
+      rendered.push({ kind: 'tool-stack', tools: toolRun });
+    }
+    toolRun = [];
+  };
+
+  blocks.forEach((block, sourceIndex) => {
+    if (block.kind === 'tool') {
+      if (rendersToolCard(block)) {
+        toolRun.push({ tool: block.tool, sourceIndex });
+        return;
+      }
+      flushToolRun();
+      rendered.push({ kind: 'tool', tool: block.tool, sourceIndex });
+      return;
+    }
+
+    flushToolRun();
+    if (block.kind === 'thinking') {
+      rendered.push({ kind: 'thinking', thinking: block.thinking, sourceIndex });
+    } else if (block.kind === 'text') {
+      rendered.push({ kind: 'text', text: block.text, sourceIndex });
+    } else if (block.kind === 'agent') {
+      rendered.push({ kind: 'agent', member: block.member, sourceIndex });
+    } else {
+      rendered.push({ kind: 'agentGroup', members: block.members, sourceIndex });
+    }
+  });
+
+  flushToolRun();
+  return rendered;
+}
+
+export function turnFinalText(turn: ChatTurn): string {
+  return turnBlocks(turn)
+    .flatMap((blk) => (blk.kind === 'text' && blk.text ? [blk.text] : []))
+    .join('\n\n');
+}
+
+/** Convert a single turn to Markdown. */
+export function turnToMarkdown(turn: ChatTurn): string {
+  const parts: string[] = [];
+  for (const blk of turnBlocks(turn)) {
+    if (blk.kind === 'thinking' && blk.thinking) {
+      parts.push(`> **Thinking**\n> ${blk.thinking.split('\n').join('\n> ')}`);
+    } else if (blk.kind === 'text' && blk.text) {
+      parts.push(blk.text);
+    } else if (blk.kind === 'tool' && blk.tool.output && blk.tool.output.length > 0) {
+      const output = blk.tool.output.join('\n');
+      parts.push(`\`\`\`\n[${blk.tool.name}]\n${output}\n\`\`\``);
+    } else if (blk.kind === 'agent') {
+      parts.push(`**Agent** ${blk.member.name} (${blk.member.phase})`);
+    } else if (blk.kind === 'agentGroup') {
+      parts.push(`**Agents**\n\n${blk.members.map((member) => `- ${member.name}: ${member.phase}`).join('\n')}`);
+    }
+  }
+  return parts.join('\n\n');
+}
+
+export function toolStackKey(item: ToolStackItem): string {
+  return item.tool.id || `tool-${item.sourceIndex}`;
+}
+
+export function renderBlockKey(block: AssistantRenderBlock, index: number): string {
+  if (block.kind === 'tool-stack') {
+    return `tool-stack-${block.tools[0]?.sourceIndex ?? index}`;
+  }
+  if (block.kind === 'tool') return toolStackKey({ tool: block.tool, sourceIndex: block.sourceIndex });
+  if (block.kind === 'agent') return `agent-${block.member.id}-${block.sourceIndex}`;
+  if (block.kind === 'agentGroup') return `agent-group-${block.members[0]?.id ?? block.sourceIndex}`;
+  return `${block.kind}-${block.sourceIndex}`;
+}

From a7e208e739a29d673c790201087c4df5b57e3c6b Mon Sep 17 00:00:00 2001
From: qer <wbxl2000@outlook.com>
Date: Tue, 23 Jun 2026 13:42:58 +0800
Subject: [PATCH 2/3] chore: add changeset for chat pane helper extraction

---
 .changeset/web-split-chatpane-helpers.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/web-split-chatpane-helpers.md

diff --git a/.changeset/web-split-chatpane-helpers.md b/.changeset/web-split-chatpane-helpers.md
new file mode 100644
index 0000000000..4606cde7e8
--- /dev/null
+++ b/.changeset/web-split-chatpane-helpers.md
@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Extract pure turn-rendering helpers out of the chat pane into their own module.

From fd9568fe344ff95c9084bc544d397e3367cfb20b Mon Sep 17 00:00:00 2001
From: qer <wbxl2000@outlook.com>
Date: Tue, 23 Jun 2026 15:14:04 +0800
Subject: [PATCH 3/3] test(kimi-web): cover chat turn-rendering helpers

Pure-logic tests for the helpers extracted from ChatPane, focused on
assistantRenderBlocks (tool-stack grouping, interrupt/media break, single
tool) plus the formatting/boundary helpers. Doubles as a safety net
confirming the extraction preserved behavior.
---
 .../kimi-web/test/chat-turn-rendering.test.ts | 179 ++++++++++++++++++
 1 file changed, 179 insertions(+)
 create mode 100644 apps/kimi-web/test/chat-turn-rendering.test.ts

diff --git a/apps/kimi-web/test/chat-turn-rendering.test.ts b/apps/kimi-web/test/chat-turn-rendering.test.ts
new file mode 100644
index 0000000000..77916465ac
--- /dev/null
+++ b/apps/kimi-web/test/chat-turn-rendering.test.ts
@@ -0,0 +1,179 @@
+import { describe, expect, it } from 'vitest';
+import type { ChatTurn, ToolCall, TurnBlock } from '../src/types';
+import {
+  assistantRenderBlocks,
+  formatDuration,
+  formatTokens,
+  rendersToolCard,
+  renderBlockKey,
+  toolStackPosition,
+  turnBlocks,
+  turnFinalText,
+  turnToMarkdown,
+} from '../src/components/chatTurnRendering';
+
+function tool(id: string, over: Partial<ToolCall> = {}): ToolCall {
+  return { id, name: 'read', arg: `· ${id}.ts`, status: 'ok', ...over };
+}
+
+function toolBlock(id: string, over: Partial<ToolCall> = {}): Extract<TurnBlock, { kind: 'tool' }> {
+  return { kind: 'tool', tool: tool(id, over) };
+}
+
+function assistantTurn(blocks: TurnBlock[], over: Partial<ChatTurn> = {}): ChatTurn {
+  return { id: 't1', role: 'assistant', no: 1, text: '', blocks, ...over };
+}
+
+describe('formatTokens', () => {
+  it('keeps small counts verbatim and abbreviates at the k / M thresholds', () => {
+    expect(formatTokens(0)).toBe('0');
+    expect(formatTokens(999)).toBe('999');
+    expect(formatTokens(1000)).toBe('1.0k');
+    expect(formatTokens(1500)).toBe('1.5k');
+    expect(formatTokens(1_000_000)).toBe('1.0M');
+    expect(formatTokens(2_500_000)).toBe('2.5M');
+  });
+});
+
+describe('formatDuration', () => {
+  it('switches units at the 1s and 1m boundaries', () => {
+    expect(formatDuration(999)).toBe('999ms');
+    expect(formatDuration(1000)).toBe('1.0s');
+    expect(formatDuration(59_999)).toBe('60.0s');
+    expect(formatDuration(60_000)).toBe('1m0.0s');
+    expect(formatDuration(90_500)).toBe('1m30.5s');
+  });
+});
+
+describe('turnBlocks', () => {
+  it('returns the ordered blocks as-is when present', () => {
+    const blocks: TurnBlock[] = [{ kind: 'text', text: 'hi' }];
+    expect(turnBlocks(assistantTurn(blocks))).toBe(blocks);
+  });
+
+  it('falls back to thinking -> text -> tools order when blocks are absent', () => {
+    const turn: ChatTurn = {
+      id: 't1',
+      role: 'assistant',
+      no: 1,
+      text: 'answer',
+      thinking: 'plan',
+      tools: [tool('a')],
+    };
+    expect(turnBlocks(turn)).toEqual([
+      { kind: 'thinking', thinking: 'plan' },
+      { kind: 'text', text: 'answer' },
+      { kind: 'tool', tool: tool('a') },
+    ]);
+  });
+});
+
+describe('rendersToolCard', () => {
+  it('hides the card only for a successful tool that carries inline media', () => {
+    expect(rendersToolCard(toolBlock('a'))).toBe(true);
+    expect(rendersToolCard(toolBlock('r', { status: 'running' }))).toBe(true);
+    expect(
+      rendersToolCard(toolBlock('m', { status: 'ok', media: { kind: 'image', url: 'x' } })),
+    ).toBe(false);
+    // media but errored -> still rendered as a card
+    expect(
+      rendersToolCard(toolBlock('e', { status: 'error', media: { kind: 'image', url: 'x' } })),
+    ).toBe(true);
+  });
+});
+
+describe('toolStackPosition', () => {
+  it('marks a lone tool single and otherwise reports first/middle/last', () => {
+    expect(toolStackPosition(0, 1)).toBe('single');
+    expect(toolStackPosition(0, 0)).toBe('single');
+    expect(toolStackPosition(0, 3)).toBe('first');
+    expect(toolStackPosition(1, 3)).toBe('middle');
+    expect(toolStackPosition(2, 3)).toBe('last');
+  });
+});
+
+describe('assistantRenderBlocks', () => {
+  it('groups consecutive renderable tools into one tool-stack', () => {
+    const rendered = assistantRenderBlocks(assistantTurn([toolBlock('a'), toolBlock('b')]));
+    expect(rendered).toHaveLength(1);
+    expect(rendered[0]).toMatchObject({ kind: 'tool-stack' });
+    if (rendered[0]?.kind === 'tool-stack') {
+      expect(rendered[0].tools.map((t) => t.tool.id)).toEqual(['a', 'b']);
+      expect(rendered[0].tools.map((t) => t.sourceIndex)).toEqual([0, 1]);
+    }
+  });
+
+  it('renders a lone tool as a standalone tool, not a stack', () => {
+    const rendered = assistantRenderBlocks(assistantTurn([toolBlock('a')]));
+    expect(rendered).toEqual([{ kind: 'tool', tool: tool('a'), sourceIndex: 0 }]);
+  });
+
+  it('breaks the stack when a non-tool block interrupts the run', () => {
+    const rendered = assistantRenderBlocks(
+      assistantTurn([toolBlock('a'), { kind: 'text', text: 'x' }, toolBlock('b')]),
+    );
+    expect(rendered.map((b) => b.kind)).toEqual(['tool', 'text', 'tool']);
+  });
+
+  it('breaks the stack when a media tool (no card) interrupts the run', () => {
+    const rendered = assistantRenderBlocks(
+      assistantTurn([
+        toolBlock('a'),
+        toolBlock('b'),
+        toolBlock('c', { status: 'ok', media: { kind: 'image', url: 'x' } }),
+      ]),
+    );
+    expect(rendered.map((b) => b.kind)).toEqual(['tool-stack', 'tool']);
+    if (rendered[0]?.kind === 'tool-stack') {
+      expect(rendered[0].tools.map((t) => t.tool.id)).toEqual(['a', 'b']);
+    }
+  });
+
+  it('preserves thinking/text order with their source indexes', () => {
+    const rendered = assistantRenderBlocks(
+      assistantTurn([
+        { kind: 'thinking', thinking: 'plan' },
+        { kind: 'text', text: 'answer' },
+      ]),
+    );
+    expect(rendered).toEqual([
+      { kind: 'thinking', thinking: 'plan', sourceIndex: 0 },
+      { kind: 'text', text: 'answer', sourceIndex: 1 },
+    ]);
+  });
+});
+
+describe('turnFinalText', () => {
+  it('joins only the text blocks, dropping thinking and tools', () => {
+    const turn = assistantTurn([
+      { kind: 'thinking', thinking: 'plan' },
+      { kind: 'text', text: 'first' },
+      toolBlock('a'),
+      { kind: 'text', text: 'second' },
+    ]);
+    expect(turnFinalText(turn)).toBe('first\n\nsecond');
+  });
+});
+
+describe('turnToMarkdown', () => {
+  it('renders thinking as a quote, text verbatim, and tool output as a fenced block', () => {
+    const turn = assistantTurn([
+      { kind: 'thinking', thinking: 'line1\nline2' },
+      { kind: 'text', text: 'hello' },
+      toolBlock('a', { name: 'bash', output: ['out1', 'out2'] }),
+    ]);
+    expect(turnToMarkdown(turn)).toBe(
+      ['> **Thinking**\n> line1\n> line2', 'hello', '```\n[bash]\nout1\nout2\n```'].join('\n\n'),
+    );
+  });
+});
+
+describe('renderBlockKey', () => {
+  it('derives stable keys per block kind', () => {
+    expect(renderBlockKey({ kind: 'text', text: 'x', sourceIndex: 2 }, 0)).toBe('text-2');
+    expect(renderBlockKey({ kind: 'tool', tool: tool('a'), sourceIndex: 3 }, 0)).toBe('a');
+    expect(
+      renderBlockKey({ kind: 'tool-stack', tools: [{ tool: tool('a'), sourceIndex: 5 }] }, 0),
+    ).toBe('tool-stack-5');
+  });
+});