fix(fs): persist read window offset in the read card meta

An empty read window (byte cap below the first selected line: `lines: []` with `totalLines > 0`) dropped `offset` from the persisted presentation meta, so a replayed read card could not report where the window starts or where a continuation resumes. Carry `offset` on `FsReadMeta`, `ReadResultView`, and the `presentationMeta` projection, and validate it in `readMetaFromMeta` (1-based integer; the first line number may not fall below it). Re-record the ACP fixtures and the cordis api catalog. Also correct the Note's `parallel-file-reads` golden path (examples/tui-agent -> apps/cli) and record the pre-card replay-degradation tradeoff in the Decision section.
2026-07-30 22:00:35 +08:00
parent ca19468ae2
commit 4fbe46c381
24 changed files with 75 additions and 42 deletions
--- a/packages/cordis/tool-cordis/src/api-catalog.ts
+++ b/packages/cordis/tool-cordis/src/api-catalog.ts
@@ -2101,7 +2101,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
  },
  {
    name: 'ReadResultView',
-    declaration: 'export interface ReadResultView {\n    card: \'read\';\n    title?: string;\n    path: string;\n    lines: ReadFileLine[];\n    totalLines: number;\n    lang?: string;\n    content?: ContentBlock[];\n}',
+    declaration: 'export interface ReadResultView {\n    card: \'read\';\n    title?: string;\n    path: string;\n    offset: number;\n    lines: ReadFileLine[];\n    totalLines: number;\n    lang?: string;\n    content?: ContentBlock[];\n}',
  },
  {
    name: 'ReasoningBlock',
--- a/packages/core/tools/README.i18n.yaml
+++ b/packages/core/tools/README.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 packages/core/tools/README.md
-README.md: bff80e34d8b8a03424263ae978fe43c143bcb4fa
-README.zh.md: 9d141cdfe91f14420bcd5a394b8bbd5871407b42
+README.md: dc3d059c1ce16f11cb0650e266762eb6d7466e34
+README.zh.md: 8d1ee0139b2d311fed07a0673cd772222ae22032
--- a/packages/core/tools/README.md
+++ b/packages/core/tools/README.md
@@ -108,7 +108,7 @@ Optional `isConcurrencySafe(args)` receives typed, softly validated arguments. E
 Tools optionally own pure `presentCall()` and `presentResult()` render intents, so UIs do not special-case tool names:

 - Call views are `{ card: 'generic', title, kind?, rawInput?, content?, locations? }`, `{ card: 'terminal', title, description?, cwd? }`, or `{ card: 'diff', title, diffs, locations? }`.
- Result views are `{ card: 'generic', title?, content? }`, `{ card: 'terminal', title?, output?, exitCode?, signal? }`, `{ card: 'diff', title?, diffs }`, or `{ card: 'read', title?, path, lines, totalLines, lang?, content? }` (a completed file read → a line-numbered, optionally syntax-highlighted code view; `lines` is `{ number, text }[]` keeping each file line number, and `content` is the envelope-stripped text a UI without read support falls back to).
+- Result views are `{ card: 'generic', title?, content? }`, `{ card: 'terminal', title?, output?, exitCode?, signal? }`, `{ card: 'diff', title?, diffs }`, or `{ card: 'read', title?, path, offset, lines, totalLines, lang?, content? }` (a completed file read → a line-numbered, optionally syntax-highlighted code view; `offset` is the 1-based first line the window requested, kept even when `lines` is empty; `lines` is `{ number, text }[]` keeping each file line number, and `content` is the envelope-stripped text a UI without read support falls back to).

 Returning `undefined` selects generic fallback. Presenters depend only on their arguments and the durable result because UIs call them during live streaming and log replay. `output.presentationMeta(args, value)` derives JSON metadata for direct surface calls; that metadata persists with `tool/result` and returns to `presentResult`, while the canonical value itself remains execution-local and is never replayed. Nested Code dispatches do not compute metadata. `defineTool` soft-validates older logged arguments and falls back instead of crashing replay. `dsh-tool-bash` and `dsh-tool-fs` are the reference implementations; the [canonical-output Agent Note](../../../.agents/notes/implemented/architecture/2026-07-20-canonical-tool-output-contract.md) owns the value/presentation split and the [render-intent Agent Note](../../../.agents/notes/implemented/architecture/2026-07-02-tool-render-intent-union.md) owns card vocabulary.

--- a/packages/core/tools/README.zh.md
+++ b/packages/core/tools/README.zh.md
@@ -108,7 +108,7 @@ ctx.tools.register(defineTool({
 工具可以选择拥有纯 `presentCall()` 和 `presentResult()` 呈现意图，使 UI 无需特殊处理工具名称：

 - 调用视图为 `{ card: 'generic', title, kind?, rawInput?, content?, locations? }`、`{ card: 'terminal', title, description?, cwd? }` 或 `{ card: 'diff', title, diffs, locations? }`。
- 结果视图为 `{ card: 'generic', title?, content? }`、`{ card: 'terminal', title?, output?, exitCode?, signal? }`、`{ card: 'diff', title?, diffs }` 或 `{ card: 'read', title?, path, lines, totalLines, lang?, content? }`（已完成的文件读取→带行号、可选语法高亮的代码视图；`lines` 是 `{ number, text }[]`，保留每一行的文件行号，`content` 是无读取能力的 UI 回退时使用的去信封文本）。
+- 结果视图为 `{ card: 'generic', title?, content? }`、`{ card: 'terminal', title?, output?, exitCode?, signal? }`、`{ card: 'diff', title?, diffs }` 或 `{ card: 'read', title?, path, offset, lines, totalLines, lang?, content? }`（已完成的文件读取→带行号、可选语法高亮的代码视图；`offset` 是窗口请求的 1-based 起始行，即使 `lines` 为空也保留；`lines` 是 `{ number, text }[]`，保留每一行的文件行号，`content` 是无读取能力的 UI 回退时使用的去信封文本）。

 返回 `undefined` 会选择通用回退。呈现器只依赖其参数和持久结果，因为 UI 会在实时流式输出和日志回放期间调用它们。`output.presentationMeta(args, value)` 为直接接口调用派生 JSON 元数据；该元数据随 `tool/result` 持久化并传回 `presentResult`，而规范值本身仍只存在于执行局部，绝不会回放。嵌套 Code 分发不会计算元数据。`defineTool` 会软验证较旧的日志参数并回退，而不会使回放崩溃。`dsh-tool-bash` 与 `dsh-tool-fs` 是参考实现；[规范输出 Agent Note](../../../.agents/notes/implemented/architecture/2026-07-20-canonical-tool-output-contract.md) 规定值／呈现拆分，[呈现意图 Agent Note](../../../.agents/notes/implemented/architecture/2026-07-02-tool-render-intent-union.md) 规定卡片词汇。

--- a/packages/core/tools/src/presentation.ts
+++ b/packages/core/tools/src/presentation.ts
@@ -207,6 +207,12 @@ export interface ReadResultView {
  title?: string
  /** The read file's path (the model-facing path; the bridge relativizes it). */
  path: string
+  /**
+   * The 1-based first line the window requested, preserved even when `lines` is
+   * empty (a byte cap below the first selected line yields an empty window) so a
+   * UI knows where the window starts and where a continuation resumes.
+   */
+  offset: number
  /** The returned window's lines, in file order, each keeping its file line number. */
  lines: ReadFileLine[]
  /** Exact total line count in the file, so a UI can show a "showing N of M" affordance. */
--- a/packages/fs/tool-fs/README.i18n.yaml
+++ b/packages/fs/tool-fs/README.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 packages/fs/tool-fs/README.md
-README.md: 9e72ed53324d5f5efeaf659427c02d826221425c
-README.zh.md: aa94a7f6144b6cc6da34b059f5699312737d38a2
+README.md: c00b59fed06249e6d9479c4a809cdf7d78f93239
+README.zh.md: f90fbb36391c1388ab0f6836daa2a9061d046be6
--- a/packages/fs/tool-fs/README.md
+++ b/packages/fs/tool-fs/README.md
@@ -34,7 +34,7 @@ All keys are optional; the defaults are the shipped read caps.

 Field names are snake_case to match Claude Code and existing harness tool schemas.

-Canonical successes are `read` → `{ path, offset, lines: [{ number, text }], totalLines }`, `write` → `{ path, operation: 'create' | 'update', before: string | null, after }`, and `edit` → `{ path, before, after }`. Native renderers preserve the line-numbered read and mutation acknowledgements below. `write`/`edit` derive replayable diff-card metadata, and `read` derives a replayable read-card window `{ path, lines, totalLines, lang? }`, from these canonical values; the canonical values themselves are execution-local and are not added to `tool/result`, only the derived presentation metadata is persisted.
+Canonical successes are `read` → `{ path, offset, lines: [{ number, text }], totalLines }`, `write` → `{ path, operation: 'create' | 'update', before: string | null, after }`, and `edit` → `{ path, before, after }`. Native renderers preserve the line-numbered read and mutation acknowledgements below. `write`/`edit` derive replayable diff-card metadata, and `read` derives a replayable read-card window `{ path, offset, lines, totalLines, lang? }`, from these canonical values; the canonical values themselves are execution-local and are not added to `tool/result`, only the derived presentation metadata is persisted.

 ## The tool is the executor; policy is an event gate

--- a/packages/fs/tool-fs/README.zh.md
+++ b/packages/fs/tool-fs/README.zh.md
@@ -34,7 +34,7 @@ await ctx.plugin(ToolFs)                                  // this package — re

 字段名使用 snake_case，与 Claude Code 和现有 harness 工具 schema 一致。

-规范成功值分别为：`read` → `{ path, offset, lines: [{ number, text }], totalLines }`，`write` → `{ path, operation: 'create' | 'update', before: string | null, after }`，`edit` → `{ path, before, after }`。原生渲染器会保留下方带行号的读取结果和变更确认。`write`/`edit` 从这些规范值派生可回放的 diff 卡片元数据，`read` 派生可回放的读取卡片窗口 `{ path, lines, totalLines, lang? }`；规范值本身仅限于本次执行，不会添加到 `tool/result`，只有派生出的呈现元数据会被持久化。
+规范成功值分别为：`read` → `{ path, offset, lines: [{ number, text }], totalLines }`，`write` → `{ path, operation: 'create' | 'update', before: string | null, after }`，`edit` → `{ path, before, after }`。原生渲染器会保留下方带行号的读取结果和变更确认。`write`/`edit` 从这些规范值派生可回放的 diff 卡片元数据，`read` 派生可回放的读取卡片窗口 `{ path, offset, lines, totalLines, lang? }`；规范值本身仅限于本次执行，不会添加到 `tool/result`，只有派生出的呈现元数据会被持久化。

 ## 工具就是执行器；策略是事件门禁

--- a/packages/fs/tool-fs/src/read-render.ts
+++ b/packages/fs/tool-fs/src/read-render.ts
@@ -220,6 +220,8 @@ export function langFromPath(path: string): string | undefined {
 export interface FsReadMeta {
  /** The read file's model-facing path. */
  path: string
+  /** The 1-based first line the window requested, kept even when `lines` is empty. */
+  offset: number
  /** The returned window's lines, each keeping its file line number. */
  lines: FileTextLine[]
  /** Exact total line count in the file. */
@@ -245,24 +247,26 @@ function isFileTextLine(value: unknown): value is FileTextLine {
 * Malformed metadata returns `undefined` so presentation can fall back to the
 * generic text card instead of throwing during replay. Beyond shape, the
 * semantic contract of a read window is enforced against replayed JSON that is
- * well-typed but out of range: `totalLines` must be a non-negative integer, each
- * line number must be a 1-based integer, the line numbers must strictly increase,
- * and no line number may exceed `totalLines`. Any violation declines to the
- * generic fallback rather than emitting a card that misnumbers or overcounts.
+ * well-typed but out of range: `offset` must be a 1-based integer, `totalLines`
+ * must be a non-negative integer, each line number must be a 1-based integer no
+ * less than `offset`, the line numbers must strictly increase, and no line number
+ * may exceed `totalLines`. Any violation declines to the generic fallback rather
+ * than emitting a card that misnumbers or overcounts.
 * @param meta - result metadata.
 * @returns the validated read window, or `undefined` for absent, malformed, or semantically invalid data.
 */
 export function readMetaFromMeta(meta: unknown): FsReadMeta | undefined {
  if (typeof meta !== 'object' || meta === null || Array.isArray(meta)) return undefined
-  const { path, lines, totalLines, lang } = meta as Record<string, unknown>
-  if (typeof path !== 'string' || typeof totalLines !== 'number') return undefined
+  const { path, offset, lines, totalLines, lang } = meta as Record<string, unknown>
+  if (typeof path !== 'string' || typeof totalLines !== 'number' || typeof offset !== 'number') return undefined
+  if (!Number.isInteger(offset) || offset < 1) return undefined
  if (!Number.isInteger(totalLines) || totalLines < 0) return undefined
  if (!Array.isArray(lines) || !lines.every(isFileTextLine)) return undefined
  if (lang !== undefined && typeof lang !== 'string') return undefined
-  let previous = 0
+  let previous = offset - 1
  for (const { number } of lines) {
    if (number <= previous || number > totalLines) return undefined
    previous = number
  }
-  return { path, lines, totalLines, ...lang === undefined ? {} : { lang } }
+  return { path, offset, lines, totalLines, ...lang === undefined ? {} : { lang } }
 }
--- a/packages/fs/tool-fs/src/read.ts
+++ b/packages/fs/tool-fs/src/read.ts
@@ -125,6 +125,7 @@ export function applyReadTool(ctx: Context, caps: ReadToolCaps): void {
        const lang = langFromPath(value.path)
        return {
          path: value.path,
+          offset: value.offset,
          lines: value.lines.map(({ number, text }) => ({ number, text })),
          totalLines: value.totalLines,
          ...lang === undefined ? {} : { lang },
@@ -186,6 +187,7 @@ export function applyReadTool(ctx: Context, caps: ReadToolCaps): void {
      return {
        card: 'read',
        path: meta.path,
+        offset: meta.offset,
        lines: meta.lines,
        totalLines: meta.totalLines,
        ...meta.lang === undefined ? {} : { lang: meta.lang },
--- a/packages/fs/tool-fs/tests/read-render.spec.ts
+++ b/packages/fs/tool-fs/tests/read-render.spec.ts
@@ -151,14 +151,19 @@ describe('langFromPath', () => {
 })

 describe('readMetaFromMeta', () => {
-  const good = { path: '/abs/a.ts', lines: [{ number: 1, text: 'x' }], totalLines: 1, lang: 'ts' }
+  const good = { path: '/abs/a.ts', offset: 1, lines: [{ number: 1, text: 'x' }], totalLines: 1, lang: 'ts' }

  it('narrows a well-formed read meta, with and without a lang hint', () => {
    expect(readMetaFromMeta(good)).toEqual(good)
-    const noLang = { path: '/abs/a', lines: [], totalLines: 0 }
+    const noLang = { path: '/abs/a', offset: 1, lines: [], totalLines: 0 }
    expect(readMetaFromMeta(noLang)).toEqual(noLang)
  })

+  it('narrows an empty window at a positive offset (byte cap below the first selected line)', () => {
+    const empty = { path: '/abs/a', offset: 5, lines: [], totalLines: 9 }
+    expect(readMetaFromMeta(empty)).toEqual(empty)
+  })
+
  it('returns undefined for absent, non-object, or array meta', () => {
    expect(readMetaFromMeta(undefined)).toBeUndefined()
    expect(readMetaFromMeta(null)).toBeUndefined()
@@ -168,6 +173,7 @@ describe('readMetaFromMeta', () => {

  it('returns undefined when a field is missing or the wrong type (defensive narrowing)', () => {
    expect(readMetaFromMeta({ ...good, path: 5 })).toBeUndefined()
+    expect(readMetaFromMeta({ ...good, offset: '1' })).toBeUndefined()
    expect(readMetaFromMeta({ ...good, totalLines: '1' })).toBeUndefined()
    expect(readMetaFromMeta({ ...good, lines: 'nope' })).toBeUndefined()
    expect(readMetaFromMeta({ ...good, lines: [{ number: '1', text: 'x' }] })).toBeUndefined()
@@ -176,6 +182,17 @@ describe('readMetaFromMeta', () => {
    expect(readMetaFromMeta({ ...good, lang: 5 })).toBeUndefined()
  })

+  it('rejects an offset that is not a 1-based integer', () => {
+    expect(readMetaFromMeta({ ...good, offset: 0 })).toBeUndefined()
+    expect(readMetaFromMeta({ ...good, offset: 1.5 })).toBeUndefined()
+    expect(readMetaFromMeta({ ...good, offset: NaN })).toBeUndefined()
+    expect(readMetaFromMeta({ ...good, offset: Infinity })).toBeUndefined()
+  })
+
+  it('rejects a first line number below offset', () => {
+    expect(readMetaFromMeta({ ...good, offset: 2, lines: [{ number: 1, text: 'x' }], totalLines: 2 })).toBeUndefined()
+  })
+
  it('rejects a line number that is not a 1-based integer', () => {
    expect(readMetaFromMeta({ ...good, lines: [{ number: 0, text: 'x' }], totalLines: 1 })).toBeUndefined()
    expect(readMetaFromMeta({ ...good, lines: [{ number: 1.5, text: 'x' }], totalLines: 2 })).toBeUndefined()
@@ -190,7 +207,7 @@ describe('readMetaFromMeta', () => {
  })

  it('rejects lines that do not strictly increase or exceed totalLines', () => {
-    const twoLines = { path: '/abs/a', lang: 'ts' }
+    const twoLines = { path: '/abs/a', offset: 1, lang: 'ts' }
    // Duplicate line numbers.
    expect(readMetaFromMeta({ ...twoLines, lines: [{ number: 1, text: 'a' }, { number: 1, text: 'b' }], totalLines: 2 })).toBeUndefined()
    // Out-of-order line numbers.
--- a/packages/fs/tool-fs/tests/tools.spec.ts
+++ b/packages/fs/tool-fs/tests/tools.spec.ts
@@ -329,6 +329,7 @@ describe('read tool', () => {
    // The extension drives the lang hint; the window rides on persisted meta.
    expect(result.meta).toEqual({
      path: '/abs/a.ts',
+      offset: 1,
      lines: [{ number: 1, text: 'const x = 1' }, { number: 2, text: 'const y = 2' }],
      totalLines: 2,
      lang: 'ts',
@@ -337,6 +338,7 @@ describe('read tool', () => {
    expect(view).toEqual({
      card: 'read',
      path: '/abs/a.ts',
+      offset: 1,
      lines: [{ number: 1, text: 'const x = 1' }, { number: 2, text: 'const y = 2' }],
      totalLines: 2,
      lang: 'ts',
@@ -349,7 +351,7 @@ describe('read tool', () => {
    fs.files.set('key:notes', 'plain')
    const result = await call(ctx, 'read', { file_path: 'notes' })
    if (result.isError) throw new Error('expected read success')
-    expect(result.meta).toEqual({ path: '/abs/notes', lines: [{ number: 1, text: 'plain' }], totalLines: 1 })
+    expect(result.meta).toEqual({ path: '/abs/notes', offset: 1, lines: [{ number: 1, text: 'plain' }], totalLines: 1 })
  })
 })

@@ -485,7 +487,7 @@ describe('tool-owned presentation (pure presentCall)', () => {
    // The structured line data rides on persisted meta (the raw output object is
    // not on the wire); presentResult narrows it and appends the stripped text as
    // the no-capability `content` fallback.
-    const meta = { path: '/tmp/a.ts', lines: [{ number: 1, text: 'hello' }], totalLines: 1, lang: 'ts' }
+    const meta = { path: '/tmp/a.ts', offset: 1, lines: [{ number: 1, text: 'hello' }], totalLines: 1, lang: 'ts' }
    expect(await presentResult('read', { file_path: 'a.ts' }, {
      content: [{ type: 'text', text: '<path>/tmp/a.ts</path>\n<type>file</type>\n<content>\n1: hello\n\n(End of file - total 1 lines)\n</content>' }],
      isError: false,
@@ -493,6 +495,7 @@ describe('tool-owned presentation (pure presentCall)', () => {
    })).toEqual({
      card: 'read',
      path: '/tmp/a.ts',
+      offset: 1,
      lines: [{ number: 1, text: 'hello' }],
      totalLines: 1,
      lang: 'ts',
@@ -502,10 +505,11 @@ describe('tool-owned presentation (pure presentCall)', () => {
    expect(await presentResult('read', { file_path: 'notes' }, {
      content: [{ type: 'text', text: '<path>/tmp/notes</path>\n<type>file</type>\n<content>\nbody\n</content>' }],
      isError: false,
-      meta: { path: '/tmp/notes', lines: [{ number: 1, text: 'body' }], totalLines: 1 },
+      meta: { path: '/tmp/notes', offset: 1, lines: [{ number: 1, text: 'body' }], totalLines: 1 },
    })).toEqual({
      card: 'read',
      path: '/tmp/notes',
+      offset: 1,
      lines: [{ number: 1, text: 'body' }],
      totalLines: 1,
      content: [{ type: 'text', text: 'body' }],