diff --git a/apps/web/tests/expected/markdown-mermaid/ui.expected.md b/apps/web/tests/expected/markdown-mermaid/ui.expected.md
index 58657a3bf6..ac9ceb3164 100644
--- a/apps/web/tests/expected/markdown-mermaid/ui.expected.md
+++ b/apps/web/tests/expected/markdown-mermaid/ui.expected.md
@@ -1,17 +1,3 @@
-- banner:
-  - navigation "Session hierarchy":
-    - button "Mermaid previews" [disabled]
-  - button "Session log":
-    - text: Session log
-    - img
-  - button "Open the sidebar":
-    - img
-  - tablist:
-    - tab "Chat" [selected]
-    - tab "Trajectory"
-- text: Preview these Mermaid diagrams. {{clock}}
-- button "Copy":
-  - img
 - heading "Mermaid previews" [level=1]
 - button "Source"
 - button "Copy"
@@ -27,26 +13,3 @@
 - button "Source"
 - button "Copy"
 - img "Mermaid diagram"
-- button "Copy":
-  - img
-- button "Good response":
-  - img
-- button "Bad response":
-  - img
-- button "Branch into a new conversation":
-  - img
-- button "Ran for {{duration}}":
-  - img
-  - text: Ran for {{duration}}
-- text: {{clock}}
-- textbox "Message or run a task... / commands, @ files or sessions"
-- button "Commands":
-  - img
-- button "Add attachment":
-  - img
-- 'button "Access mode, current: Workspace Write"': Workspace Write
-- button "Select model, current DeepSeek-V4-Flash":
-  - text: DeepSeek-V4-Flash
-  - img
-- button "Send message" [disabled]
-- text: 1 turns · 1 steps LLM {{duration}}
diff --git a/apps/web/tests/expected/markdown-mermaid/zh.expected.md b/apps/web/tests/expected/markdown-mermaid/zh.expected.md
index e3a3b84157..066e88f589 100644
--- a/apps/web/tests/expected/markdown-mermaid/zh.expected.md
+++ b/apps/web/tests/expected/markdown-mermaid/zh.expected.md
@@ -1,17 +1,3 @@
-- banner:
-  - navigation "会话层级":
-    - button "Mermaid previews" [disabled]
-  - button "Session 日志":
-    - text: Session 日志
-    - img
-  - button "展开侧栏":
-    - img
-  - tablist:
-    - tab "对话" [selected]
-    - tab "轨迹"
-- text: Preview these Mermaid diagrams. {{clock}}
-- button "复制":
-  - img
 - heading "Mermaid previews" [level=1]
 - button "源码"
 - button "复制"
@@ -26,26 +12,3 @@
 - button "源码"
 - button "复制"
 - img "Mermaid 图表"
-- button "复制":
-  - img
-- button "好的回答":
-  - img
-- button "有问题的回答":
-  - img
-- button "在新对话中分支":
-  - img
-- button "用时 {{duration}}":
-  - img
-  - text: 用时 {{duration}}
-- text: {{clock}}
-- textbox "发消息或做任务… / 调用指令 @ 文件或对话"
-- button "指令":
-  - img
-- button "添加附件":
-  - img
-- button "访问模式，当前：工作区内修改": 工作区内修改
-- button "选择模型，当前 DeepSeek-V4-Flash":
-  - text: DeepSeek-V4-Flash
-  - img
-- button "发送消息" [disabled]
-- text: 1 轮 · 1 步 LLM {{duration}}
diff --git a/apps/web/tests/markdown-mermaid.e2e.ts b/apps/web/tests/markdown-mermaid.e2e.ts
index 928e6cbf40..82789caa63 100644
--- a/apps/web/tests/markdown-mermaid.e2e.ts
+++ b/apps/web/tests/markdown-mermaid.e2e.ts
@@ -15,6 +15,7 @@ import { newEnglishPage, saveFailureShot } from './support.ts'
 const SNAPSHOT_DIR = fileURLToPath(new URL('./expected/markdown-mermaid', import.meta.url))
 const MODE = webSnapshotMode()
 const SEED_ID = 'markdown-mermaid-web-e2e'
+const DIAGRAM_MESSAGE = '[class*="markdown"]:has(.md-code-block)'
 const FLOW = 'flowchart LR\n  A[输入] --> B[共享渲染器] --> C[图形预览]'
 const SEQUENCE = 'sequenceDiagram\n  participant U as User\n  participant R as Renderer\n  U->>R: Mermaid source\n  R-->>U: Diagram'
 const INVALID = 'flowchart LR\n  A[unfinished'
@@ -122,8 +123,7 @@ describe('web e2e: Mermaid chat previews', () => {
     expect(tripwire.warnings).toEqual([])
     await page.getByRole('heading', { name: 'Mermaid previews' }).click()
     await page.mouse.move(0, 0)
-    const snapshot = (await captureStableAria(page, '[class*="centerCol"]', scaffold.workspaceCwd))
-      .split(SEED_ID).join('{{seededId}}')
+    const snapshot = await captureStableAria(page, DIAGRAM_MESSAGE, scaffold.workspaceCwd)
     await compareOrRefreshGolden(join(SNAPSHOT_DIR, 'ui.expected.md'), snapshot, MODE)
     await page.close()
   }, 60_000)
@@ -142,8 +142,7 @@ describe('web e2e: Mermaid chat previews', () => {
     await expect.poll(() => firstImage.evaluate(node => (node as HTMLImageElement).naturalWidth)).toBeGreaterThan(0)
     expect(await controls.evaluate(node => node.getBoundingClientRect().top))
       .toBeGreaterThanOrEqual(await firstImage.evaluate(node => node.getBoundingClientRect().bottom))
-    const snapshot = (await captureStableAria(page, '[class*="centerCol"]', scaffold.workspaceCwd))
-      .split(SEED_ID).join('{{seededId}}')
+    const snapshot = await captureStableAria(page, DIAGRAM_MESSAGE, scaffold.workspaceCwd)
     await compareOrRefreshGolden(join(SNAPSHOT_DIR, 'zh.expected.md'), snapshot, MODE)
     await assertFixtureInventory(SNAPSHOT_DIR, ['ui.expected.md', 'zh.expected.md'])
     await page.close()