fix(editor): preserve tabs in file views

packages/fs/tool-str-replace-editor/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-str-replace-editor/README.md
-README.md: 12224537ab2ca2d2ba97e93fe8dc2192fa9ac1aa
-README.zh.md: 5481723f8a3077ee329ec202b12a67b678abc691
+README.md: 97e9e0ab9ade7c7241c1aac3e2489e055d01ff8f
+README.zh.md: 48358eb3c9d81ddad6a83c4ff3ef0cf6542096b1

packages/fs/tool-str-replace-editor/README.md

@@ -13,7 +13,7 @@ Standalone model-facing `str_replace_editor` over `ctx.fs`. It can be composed w
 
 ## Tool
 
-The schema provides `view`, `create`, `str_replace`, and `insert` over absolute paths. File views use one-based line numbers; directory views omit hidden, dependency, and Python-cache entries and descend two levels. Replacement requires one unique literal match and reports errors only in the public `old_str` vocabulary. Insert follows the selected zero-based insertion boundary without adding an implicit trailing newline. Mutations preserve tabs outside the requested edit.
+The schema provides `view`, `create`, `str_replace`, and `insert` over absolute paths. File views use one-based line numbers and preserve content tabs, so displayed text remains valid literal replacement input; directory views omit hidden, dependency, and Python-cache entries and descend two levels. Replacement requires one unique literal match and reports errors only in the public `old_str` vocabulary. Insert follows the selected zero-based insertion boundary without adding an implicit trailing newline. Mutations preserve tabs outside the requested edit.
 
 ## Model Experience
 

packages/fs/tool-str-replace-editor/README.zh.md

@@ -13,7 +13,7 @@
 
 ## 工具
 
-Schema 提供针对绝对路径的 `view`、`create`、`str_replace` 与 `insert`。文件查看使用从一开始的行号；目录查看忽略隐藏、依赖与 Python 缓存条目并下探两层。替换要求字面量唯一匹配，错误只使用公开的 `old_str` 词汇。插入遵循所选的零基插入边界，不会隐式补尾换行。修改操作会保留请求编辑范围之外的制表符。
+Schema 提供针对绝对路径的 `view`、`create`、`str_replace` 与 `insert`。文件查看使用从一开始的行号，并保留内容中的制表符，因此显示的文本仍可作为有效的字面量替换输入；目录查看忽略隐藏、依赖与 Python 缓存条目并下探两层。替换要求字面量唯一匹配，错误只使用公开的 `old_str` 词汇。插入遵循所选的零基插入边界，不会隐式补尾换行。修改操作会保留请求编辑范围之外的制表符。
 
 ## 模型体验
 

packages/fs/tool-str-replace-editor/src/index.ts

@@ -35,23 +35,6 @@ function maybeTruncate(content: string, maxOutputChars: number): string {
     : content.slice(0, maxOutputChars) + TRUNCATED_MESSAGE
 }
 
-function expandTabs(content: string, tabSize = 8): string {
-  let column = 0
-  let result = ''
-  for (const character of content) {
-    if (character === '\t') {
-      const spaces = tabSize - (column % tabSize)
-      result += ' '.repeat(spaces)
-      column += spaces
-      continue
-    }
-    result += character
-    if (character === '\n' || character === '\r') column = 0
-    else column += 1
-  }
-  return result
-}
-
 function codepointCompare(left: string, right: string): number {
   return left < right ? -1 : left > right ? 1 : 0
 }
@@ -192,9 +175,9 @@ function formatFileView(
       : allLines.slice(initialLine - 1, finalLine)
     prompt += ` with view_range=[${initialLine}, ${finalLine}]`
   }
-  const numbered = expandTabs(lines
-    .map((line, index) => `${String(initialLine + index).padStart(6, ' ')}\t${line}`)
-    .join('\n'))
+  const numbered = lines
+    .map((line, index) => `${String(initialLine + index).padStart(6, ' ')}  ${line}`)
+    .join('\n')
   return maybeTruncate(`${prompt}:\n${numbered}\n`, maxOutputChars)
 }
 

packages/fs/tool-str-replace-editor/tests/tools.spec.ts

@@ -470,11 +470,13 @@ describe('tool-str-replace-editor', () => {
     const { ctx, root, owner } = await setup()
     const path = join(root, 'Makefile')
     await writeFile(path, 'target:\n\told\nremove\n')
+    expect(text(await call(ctx, owner, { command: 'view', path })))
+      .toContain('     2  \told')
     await call(ctx, owner, {
       command: 'str_replace',
       path,
-      old_str: 'old',
-      new_str: 'new',
+      old_str: '\told',
+      new_str: '\tnew',
     })
     await call(ctx, owner, {
       command: 'str_replace',