test(web): cover TeX math rendering

.agents/notes/implemented/feature/2026-07-23-web-assistant-markdown.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write .agents/notes/implemented/feature/2026-07-23-web-assistant-markdown.md
-2026-07-23-web-assistant-markdown.md: d5074e6090699229f5c43dd93eef0fdfbfedab76
-2026-07-23-web-assistant-markdown.zh.md: 31f0fd6835c9921f544f4b6217a0c834dff79859
+2026-07-23-web-assistant-markdown.md: 347ab223c970a345ca5d7abea0edc0bf9cce6324
+2026-07-23-web-assistant-markdown.zh.md: 6898dd009373d893d3d049b83963234461f04959

.agents/notes/implemented/feature/2026-07-23-web-assistant-markdown.md

@@ -14,7 +14,7 @@ The Web conversation preserves assistant Markdown source through session events,
 
 `MarkdownText` uses `react-markdown` with `remark-gfm` to build React elements from an AST. It covers CommonMark blocks plus GFM tables, task lists, strikethrough, and autolinks without raw-HTML parsing. Fenced code routes through the shared `CodeBlock`, which highlights registered grammars with the client's shiki singleton (`--shiki-*` tokens) and falls back to plain monospace otherwise. While a turn streams, fences stay on the plain arm so growing fences are not retokenized every chunk.
 
-Visual spacing, tables, links, blockquotes, inline code, and code-block chrome follow deepsuite `@deepseek/md` (`markdown.css` / `code-block.css`) and the same `--dsw-alias-markdown-*`, `--dsw-font-markdown-*`, `--dsw-alias-border-l*`, and `--dsw-alias-label-*` tokens. Links use `--dsw-alias-state-business-primary` (deepsuite's sheet uses `--dsw-alias-brand-text`, which is blue only under newDesign; design-platform keeps brand-text near-black and is not retuned here). `CodeBlock` ships a language banner and a copy control (`复制` / `复制成功`). Citation pills, KaTeX, heading anchors, the thinking-small markdown variant, and custom □/☑ task markers are out of scope until matching product DOM exists; GFM task lists keep native checkboxes.
+Visual spacing, tables, links, blockquotes, inline code, and code-block chrome follow deepsuite `@deepseek/md` (`markdown.css` / `code-block.css`) and the same `--dsw-alias-markdown-*`, `--dsw-font-markdown-*`, `--dsw-alias-border-l*`, and `--dsw-alias-label-*` tokens. Links use `--dsw-alias-state-business-primary` (deepsuite's sheet uses `--dsw-alias-brand-text`, which is blue only under newDesign; design-platform keeps brand-text near-black and is not retuned here). `CodeBlock` ships a language banner and a copy control (`复制` / `复制成功`). Finalized text renders KaTeX through `remark-math` and `rehype-katex`; `remarkMathCompatibility` maps `\\(...\\)`, `\\[...\\]`, and block-level same-line `$$...$$` to the same standard math AST nodes. This is a narrow parser compatibility layer, not a regex rewrite or malformed-model-output repair. Streaming stays literal until finalization so incomplete formulae do not flash errors. Citation pills, heading anchors, the thinking-small markdown variant, and custom □/☑ task markers remain out of scope; GFM task lists keep native checkboxes.
 
 The dependency is explicit in `ui-primitives`; because that pure library is seeded by the Web shell, the parser and highlighter are part of the initial browser bundle.
 
@@ -38,4 +38,4 @@ Fenced code and GFM tables own horizontal overflow so long content cannot widen
 
 ## Consequences
 
-Assistant replies render semantic Markdown consistently during streaming and replay, while tool cards, reasoning rows, interactions, user bubbles, and the host protocol remain unchanged. Streaming reparses the current text after each accumulated update; incomplete Markdown can temporarily change structure, but the isolated tail bounds React invalidation and the final event does not switch renderers. Code fences share one chrome and copy path with tool and details surfaces. The initial Web shell includes the Markdown parser, GFM runtime, and shiki allowlist; cite/math/anchor/thinking-small surfaces remain deferred.
+Assistant replies render semantic Markdown consistently during streaming and replay, while tool cards, reasoning rows, interactions, user bubbles, and the host protocol remain unchanged. Streaming reparses the current text after each accumulated update; incomplete Markdown can temporarily change structure, but the isolated tail bounds React invalidation and the final event does not switch renderers. Code fences share one chrome and copy path with tool and details surfaces. The initial Web shell includes the Markdown parser, GFM runtime, KaTeX, and shiki allowlist; citation, anchor, and thinking-small surfaces remain deferred.

.agents/notes/implemented/feature/2026-07-23-web-assistant-markdown.zh.md

@@ -14,7 +14,7 @@ Web 对话通过会话事件、历史回放与流式累积保留 assistant Markd
 
 `MarkdownText` 使用 `react-markdown` 与 `remark-gfm`，从 AST 构建 React 元素。它覆盖 CommonMark 块，以及 GFM 表格、任务列表、删除线与自动链接，且不解析原始 HTML。围栏代码经共享的 `CodeBlock` 路由；该组件用客户端的 shiki 单例（`--shiki-*` token）高亮已注册语法，否则回退为纯等宽文本。轮次流式输出期间，围栏停留在纯文本分支，以免每收到一个分片就对增长中的围栏重新分词。
 
-视觉间距、表格、链接、引用块、行内代码与代码块外框遵循 deepsuite `@deepseek/md`（`markdown.css` / `code-block.css`），并使用同一套 `--dsw-alias-markdown-*`、`--dsw-font-markdown-*`、`--dsw-alias-border-l*` 与 `--dsw-alias-label-*` token。链接使用 `--dsw-alias-state-business-primary`（deepsuite 的样式表使用 `--dsw-alias-brand-text`，仅在 newDesign 下为蓝色；design-platform 将 brand-text 保持为近黑色，此处不做重新调色）。`CodeBlock` 提供语言横幅与复制控件（`复制` / `复制成功`）。引用胶囊、KaTeX、标题锚点、thinking-small markdown 变体，以及自定义 □/☑ 任务标记均不在范围内，直至存在匹配的产品 DOM；GFM 任务列表继续使用原生复选框。
+视觉间距、表格、链接、引用块、行内代码与代码块外框遵循 deepsuite `@deepseek/md`（`markdown.css` / `code-block.css`），并使用同一套 `--dsw-alias-markdown-*`、`--dsw-font-markdown-*`、`--dsw-alias-border-l*` 与 `--dsw-alias-label-*` token。链接使用 `--dsw-alias-state-business-primary`（deepsuite 的样式表使用 `--dsw-alias-brand-text`，仅在 newDesign 下为蓝色；design-platform 将 brand-text 保持为近黑色，此处不做重新调色）。`CodeBlock` 提供语言横幅与复制控件（`复制` / `复制成功`）。已完成的文本通过 `remark-math` 和 `rehype-katex` 渲染 KaTeX；`remarkMathCompatibility` 将 `\\(...\\)`、`\\[...\\]` 和块级同一行 `$$...$$` 映射为同一套标准数学 AST 节点。这是一层小范围的解析器兼容层，不是正则重写，也不修复格式错误的模型输出。流式输出在完成前保持按字面渲染，避免不完整公式闪现错误。引用胶囊、标题锚点、thinking-small markdown 变体，以及自定义 □/☑ 任务标记仍不在范围内；GFM 任务列表继续使用原生复选框。
 
 该依赖在 `ui-primitives` 中显式声明；由于这一纯库由 Web shell 预置，解析器与高亮器会成为初始浏览器 bundle 的一部分。
 
@@ -38,4 +38,4 @@ assistant 生成的链接目标地址仅限绝对 HTTP、HTTPS 与 mailto URL。
 
 ## 后果
 
-assistant 回复在流式输出与回放期间都会一致地渲染为语义化 Markdown，而工具卡片、推理行、交互、用户气泡和宿主协议保持不变。每次累积更新后，流式输出都会重新解析当前文本；未完成的 Markdown 可能暂时改变结构，但独立的尾部会限定 React 失效范围，最终事件也不会切换渲染器。代码围栏与工具及详情表层共用同一外框与复制路径。初始 Web shell 包含 Markdown 解析器、GFM 运行时与 shiki 允许列表；cite/math/anchor/thinking-small 表层仍暂缓。
+assistant 回复在流式输出与回放期间都会一致地渲染为语义化 Markdown，而工具卡片、推理行、交互、用户气泡和宿主协议保持不变。每次累积更新后，流式输出都会重新解析当前文本；未完成的 Markdown 可能暂时改变结构，但独立的尾部会限定 React 失效范围，最终事件也不会切换渲染器。代码围栏与工具及详情表层共用同一外框与复制路径。初始 Web shell 包含 Markdown 解析器、GFM 运行时、KaTeX 与 shiki 允许列表；citation、anchor 和 thinking-small 表层仍暂缓。

apps/web/tests/math-rendering.e2e.ts

@@ -0,0 +1,127 @@
+import { fileURLToPath } from 'node:url'
+import type { Browser, Page } from 'playwright'
+import { chromium } from 'playwright'
+import { afterAll, beforeAll, describe, expect, it, onTestFailed } from 'vitest'
+import { createMessage, createUserMessage } from '@deepseek-ai/dsh-llm'
+import { SESSION_FORMAT_VERSION, Session, SessionId } from '@deepseek-ai/dsh-session'
+import type {} from '@deepseek-ai/dsh-session-title'
+import {
+  assertFixtureInventory,
+  captureStableAria,
+  compareOrRefreshGolden,
+  launchWebScaffold,
+  seedSession,
+  watchConsole,
+  webSnapshotMode,
+  type WebScaffold,
+} from './scaffold.ts'
+import { newEnglishPage, saveFailureShot } from './support.ts'
+
+const SNAPSHOT_DIR = fileURLToPath(new URL('./snapshots/math-rendering', import.meta.url))
+const UI_EXPECTED = fileURLToPath(new URL('./snapshots/math-rendering/ui.expected.md', import.meta.url))
+const MODE = webSnapshotMode()
+const SEED_ID = 'math-rendering-web-e2e'
+const DONE = 'MATH_RENDERING_DONE'
+
+/** Build a settled assistant reply that exercises every supported math delimiter. */
+function mathFixture(): string {
+  const session = Session.create(SessionId('math-rendering-source'))
+  session.append('turn/start', {
+    turn: 1,
+    trigger: { kind: 'message', source: { kind: 'user' } },
+  })
+  const user = session.append('user/message', createUserMessage({
+    content: [{ type: 'text', text: 'Render this mathematical proof.' }],
+    source: { kind: 'user' },
+  }), { surfaceOp: 'append' })
+  session.append('session/title', {
+    title: 'Math rendering',
+    messageSeqs: [user.seq],
+    source: { kind: 'fallback' },
+  })
+  session.append('step/start', { turn: 1, step: 1 })
+  session.append('assistant/message', {
+    turn: 1,
+    step: 1,
+    message: createMessage({
+      role: 'assistant',
+      content: [{
+        type: 'text',
+        text: [
+          '## Math rendering',
+          '',
+          'Inline dollar $\\theta$ and backslash \\(\\frac{1}{5}\\).',
+          '',
+          '\\[\\frac{\\pi}{4} < \\theta < \\frac{\\pi}{2}\\]',
+          '',
+          '$$\\theta \\in \\left(\\frac{\\pi}{4}, \\frac{\\pi}{2}\\right). \\tag{1}$$',
+          '',
+          '| Symbol | Value |',
+          '| --- | --- |',
+          '| $\\theta$ | \\(\\frac{1}{5}\\) |',
+          '',
+          DONE,
+        ].join('\n'),
+      }],
+      source: { kind: 'model', provider: 'fixture', model: 'fixture' },
+    }),
+  }, { surfaceOp: 'append' })
+  session.append('step/end', { turn: 1, step: 1 })
+  session.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
+
+  return [
+    JSON.stringify({
+      type: 'session',
+      version: SESSION_FORMAT_VERSION,
+      id: '{{sessionId}}',
+      createdAt: 0,
+      cwd: '{{cwd}}',
+    }),
+    ...session.events.map(event => JSON.stringify(event)),
+    '',
+  ].join('\n')
+}
+
+describe('web e2e: settled Markdown math rendering', () => {
+  let scaffold: WebScaffold
+  let browser: Browser
+  let page: Page
+  let tripwire: ReturnType<typeof watchConsole>
+
+  beforeAll(async () => {
+    scaffold = await launchWebScaffold({})
+    await seedSession(scaffold, mathFixture(), SEED_ID)
+    browser = await chromium.launch()
+    page = await newEnglishPage(browser)
+    tripwire = watchConsole(page)
+    await page.goto(scaffold.baseUrl, { waitUntil: 'load' })
+    await page.waitForSelector('[class*="frame"]', { timeout: 30_000 })
+  }, 120_000)
+
+  afterAll(async () => {
+    await browser?.close()
+    await scaffold?.close()
+  })
+
+  it.skipIf(MODE === 'record')('renders the settled reply without KaTeX errors', async () => {
+    onTestFailed(() => saveFailureShot(page, 'web-e2e-math-rendering'))
+    const groupRow = page.locator('[role="treeitem"]').first()
+    await groupRow.waitFor({ timeout: 15_000 })
+    await groupRow.click()
+    const sessionRow = page.locator('[role="treeitem"]').nth(1)
+    await sessionRow.waitFor({ timeout: 10_000 })
+    await sessionRow.click()
+    await expect.poll(() => page.getByText(DONE, { exact: true }).count(), { timeout: 15_000 }).toBe(1)
+
+    await expect.poll(() => page.locator('.katex').count(), { timeout: 10_000 }).toBe(6)
+    await expect.poll(() => page.locator('.katex-display').count(), { timeout: 10_000 }).toBe(2)
+    expect(await page.locator('.katex-error').count()).toBe(0)
+
+    const snapshot = (await captureStableAria(page, '[class*="centerCol"]', scaffold.workspaceCwd))
+      .split(SEED_ID).join('{{seededId}}')
+    await compareOrRefreshGolden(UI_EXPECTED, snapshot, MODE)
+    expect(tripwire.pageErrors).toEqual([])
+    expect(tripwire.warnings).toEqual([])
+    await assertFixtureInventory(SNAPSHOT_DIR, ['ui.expected.md'])
+  }, 60_000)
+})

apps/web/tests/snapshots/math-rendering/ui.expected.md

@@ -0,0 +1,47 @@
+- banner:
+  - navigation "Session hierarchy":
+    - button "Math rendering" [disabled]
+  - tablist:
+    - tab "Chat" [selected]
+    - tab "Trajectory"
+- text: Render this mathematical proof. {{clock}}
+- button "Copy":
+  - img
+- button "Branch into a new conversation" [disabled]:
+  - img
+- text: Available only on the last message of a completed turn
+- heading "Math rendering" [level=2]
+- paragraph:
+  - text: Inline dollar
+  - math: θ
+  - text: and backslash
+  - math: 1 5
+  - text: .
+- math: π 4 < θ < π 2
+- math: θ ∈ ( π 4 , π 2 ) . (1)
+- table:
+  - rowgroup:
+    - row "Symbol Value":
+      - columnheader "Symbol"
+      - columnheader "Value"
+  - rowgroup:
+    - row:
+      - cell:
+        - math: θ
+      - cell:
+        - math: 1 5
+- paragraph: MATH_RENDERING_DONE
+- button "Copy":
+  - img
+- button "Branch into a new conversation":
+  - img
+- text: {{clock}}Ran for {{duration}}
+- textbox "Message the agent"
+- button "Commands":
+  - img
+- 'button "Access mode, current: Workspace Write"': Workspace Write
+- button "Select model":
+  - text: Select model
+  - img
+- button "Send message" [disabled]
+- text: 1 turns · 1 steps Input 0 tok · Output 0 tok

apps/web/tsconfig.json

@@ -48,6 +48,7 @@
     "tests/web-search-round.e2e.ts",
     "tests/message-actions.e2e.ts",
     "tests/markdown-images.e2e.ts",
+    "tests/math-rendering.e2e.ts",
     "tests/queue-actions.e2e.ts",
     "tests/skill-invocation-policy.e2e.ts",
     "tests/permission-policy-context.e2e.ts",

packages/client/ui-primitives/src/markdown/remarkMathCompatibility.ts

@@ -11,6 +11,7 @@ interface RemarkProcessor {
 }
 
 const previousBackslash: Previous = function (code) {
+  /* v8 ignore next -- micromark calls previous after an event has been emitted. */
   return code !== codes.backslash || this.events.at(-1)?.[1].type === types.characterEscape
 }
 
@@ -20,6 +21,7 @@ const tokenizeBackslashMathText: Tokenizer = function (effects, ok, nok) {
   return start
 
   function start(code: number | null): State | undefined {
+    /* v8 ignore next -- the text construct is dispatched only for a backslash. */
     if (code !== codes.backslash) return nok(code)
     effects.enter('mathText')
     effects.enter('mathTextSequence')
@@ -72,6 +74,7 @@ const tokenizeBackslashMathText: Tokenizer = function (effects, ok, nok) {
     return slash
 
     function slash(code: number | null): State | undefined {
+      /* v8 ignore next -- this partial construct is attempted only at a backslash. */
       if (code !== codes.backslash) return closeNok(code)
       closeEffects.enter('mathTextSequence')
       closeEffects.consume(code)
@@ -98,6 +101,7 @@ function createMathFlow(marker: number, openMarker: number, closeMarker: number,
     return start
 
     function start(code: number | null): State | undefined {
+      /* v8 ignore next -- the flow construct is dispatched only for its marker. */
       if (code !== marker) return nok(code)
       effects.enter('mathFlow')
       effects.enter('mathFlowFence')
@@ -124,6 +128,7 @@ function createMathFlow(marker: number, openMarker: number, closeMarker: number,
         return effects.attempt({ partial: true, tokenize: tokenizeClosingFence }, closed, markerValueStart)(code)
       }
       if (markdownLineEnding(code)) {
+        /* v8 ignore next -- micromark gives same-line dollar flow to remark-math before this continuation branch. */
         return multiline
           ? effects.attempt(nonLazyContinuation, afterContinuation, nok)(code)
           : nok(code)
@@ -218,7 +223,9 @@ const tokenizeNonLazyContinuation: Tokenizer = function (effects, ok, nok) {
   return start
 
   function start(code: number | null): State | undefined {
+    /* v8 ignore next -- continuation constructs are attempted only after a line ending. */
     if (code === codes.eof) return ok(code)
+    /* v8 ignore next -- continuation constructs are attempted only after a line ending. */
     if (!markdownLineEnding(code)) return nok(code)
     effects.enter(types.lineEnding)
     effects.consume(code)

packages/client/ui-primitives/tests/markdown.spec.tsx

@@ -1,7 +1,9 @@
 // @vitest-environment jsdom
 import { cleanup, fireEvent, render, screen } from '@testing-library/react'
 import { afterEach, describe, expect, it } from 'vitest'
+import type { Extension } from 'micromark-util-types'
 import { JsonBlock, MarkdownText, MessageText } from '@deepseek-ai/dsh-client-ui-primitives'
+import { remarkMathCompatibility } from '../src/markdown/remarkMathCompatibility.ts'
 
 afterEach(cleanup)
 
@@ -171,6 +173,91 @@ describe('MarkdownText', () => {
     expect(container.querySelector('a')).toBeNull()
   })
 
+  it('renders common TeX delimiters and same-line tagged display blocks after the reply settles', () => {
+    const source = [
+      'Inline dollar $\\theta$ and backslash \\(\\frac{1}{5}\\).',
+      '',
+      '\\[\\frac{\\pi}{4} < \\theta < \\frac{\\pi}{2}\\]',
+      '',
+      '$$\\theta \\in \\left(\\frac{\\pi}{4}, \\frac{\\pi}{2}\\right). \\tag{1}$$',
+      '',
+      '| Symbol | Value |',
+      '| --- | --- |',
+      '| $\\theta$ | \\(\\frac{1}{5}\\) |',
+    ].join('\n')
+    const { container } = render(<MarkdownText text={source} />)
+
+    expect(container.querySelectorAll('.katex')).toHaveLength(6)
+    expect(container.querySelectorAll('.katex-display')).toHaveLength(2)
+    expect(container.querySelector('.katex-display annotation')?.textContent).toContain('\\frac{\\pi}{4}')
+    expect([...container.querySelectorAll('.katex-display')].at(-1)?.querySelector('annotation')?.textContent)
+      .toContain('\\tag{1}')
+    expect(container.querySelector('.katex-error')).toBeNull()
+    expect(container.querySelector('table .katex')).not.toBeNull()
+  })
+
+  it('keeps backslash delimiters correct across Markdown boundaries and malformed candidates', () => {
+    const cases = [
+      {
+        source: '\\(\\alpha \\, \\beta\\)',
+        math: 1,
+        display: 0,
+      },
+      {
+        source: '\\(\\frac{1}{5}\n+\\frac{1}{7}\\)',
+        math: 1,
+        display: 0,
+      },
+      {
+        source: '> \\[\n> \\frac{1}{5}\n> \\]',
+        math: 1,
+        display: 1,
+      },
+      {
+        source: '- \\[\n  \\frac{1}{5}\n  \\]',
+        math: 1,
+        display: 1,
+      },
+    ]
+
+    for (const item of cases) {
+      const rendered = render(<MarkdownText text={item.source} />)
+      expect(rendered.container.querySelectorAll('.katex')).toHaveLength(item.math)
+      expect(rendered.container.querySelectorAll('.katex-display')).toHaveLength(item.display)
+      expect(rendered.container.querySelector('.katex-error')).toBeNull()
+      rendered.unmount()
+    }
+
+    const literal = render(<MarkdownText text={'\\\\(x\\)\n\n\\[x\n\n$$x$$ trailing'} />)
+    expect(literal.container.querySelectorAll('.katex')).toHaveLength(1)
+    expect(literal.container.querySelector('.katex-display')).toBeNull()
+    expect(literal.container.textContent).toContain('[x')
+    expect(literal.container.textContent).toContain('xxx trailing')
+  })
+
+  it('keeps ordinary dollar blocks and incomplete delimiter candidates parseable', () => {
+    const sources = [
+      '$$\n\\theta\n$$',
+      '$$$\\theta$$$',
+      '  \\[\n  \\theta\n  \\]',
+      '\\(\\theta',
+      '> \\[\nnot a quoted continuation\n\\]',
+    ]
+
+    for (const source of sources) {
+      const rendered = render(<MarkdownText text={source} />)
+      expect(rendered.container.querySelector('.katex-error')).toBeNull()
+      rendered.unmount()
+    }
+  })
+
+  it('registers the compatibility extension on a bare remark processor', () => {
+    const data: { micromarkExtensions?: Extension[] } = {}
+    remarkMathCompatibility.call({ data: () => data })
+
+    expect(data.micromarkExtensions).toHaveLength(1)
+  })
+
   it('defers TeX rendering while streaming so incomplete formulas never flash KaTeX errors', () => {
     const partial = '$$\n\\frac{\\partial \\mathbf{u}}{\\partial'
     const complete = '$$\n\\frac{\\partial \\mathbf{u}}{\\partial t}\n$$'

tsconfig.host.json

@@ -35,6 +35,7 @@
     "apps/web/tests/web-search-round.e2e.ts",
     "apps/web/tests/message-actions.e2e.ts",
     "apps/web/tests/markdown-images.e2e.ts",
+    "apps/web/tests/math-rendering.e2e.ts",
     "apps/web/tests/queue-actions.e2e.ts",
     "apps/web/tests/skill-invocation-policy.e2e.ts",
     "apps/web/tests/permission-policy-context.e2e.ts",