diff --git a/packages/builtin-tools/src/tools/FileEditTool/__tests__/utils.test.ts b/packages/builtin-tools/src/tools/FileEditTool/__tests__/utils.test.ts
index eca237141..3745c38bc 100644
--- a/packages/builtin-tools/src/tools/FileEditTool/__tests__/utils.test.ts
+++ b/packages/builtin-tools/src/tools/FileEditTool/__tests__/utils.test.ts
@@ -106,6 +106,84 @@ describe("findActualString", () => {
     const result = findActualString("hello", "");
     expect(result).toBe("");
   });
+
+  // ── Tab/space normalization (Bug #2 reproduction) ──
+
+  test("finds match when search uses spaces but file uses tabs", () => {
+    // File content uses Tab indentation
+    const fileContent = "\tif (x) {\n\t\treturn 1;\n\t}";
+    // User copies from Read output which renders tabs as spaces
+    const searchWithSpaces = "    if (x) {\n        return 1;\n    }";
+    const result = findActualString(fileContent, searchWithSpaces);
+    expect(result).not.toBeNull();
+    expect(result).toBe(fileContent);
+  });
+
+  test("finds match when search mixes tabs and spaces inconsistently", () => {
+    const fileContent = "\tconst x = 1; // comment";
+    const searchMixed = "    const x = 1; // comment";
+    const result = findActualString(fileContent, searchMixed);
+    expect(result).not.toBeNull();
+  });
+
+  test("finds match for single-line tab-to-space mismatch", () => {
+    const fileContent = "\t\torder_price = NormalizeDouble(ask, digits);";
+    const searchSpaces = "        order_price = NormalizeDouble(ask, digits);";
+    const result = findActualString(fileContent, searchSpaces);
+    expect(result).not.toBeNull();
+  });
+
+  // ── CJK / UTF-8 characters (Bug #1 reproduction) ──
+
+  test("finds match with CJK characters in content", () => {
+    const fileContent = "input int x = 620; // 止盈点数(点) — 32个pip=320点";
+    const result = findActualString(fileContent, fileContent);
+    expect(result).toBe(fileContent);
+  });
+
+  test("finds match with CJK characters when tab/space differs", () => {
+    const fileContent = "\t// 向上突破 → Sell Limit (逆方向做空)";
+    const searchSpaces = "    // 向上突破 → Sell Limit (逆方向做空)";
+    const result = findActualString(fileContent, searchSpaces);
+    expect(result).not.toBeNull();
+    expect(result).toBe(fileContent);
+  });
+
+  // ── Multiline with tabs + CJK (combined Bug #1 + #2) ──
+
+  test("finds multiline match with tabs and CJK characters", () => {
+    const fileContent = "\tif(effective_dir == BREAKOUT_UP)\n\t\t{\n\t\t\t// 向上突破\n\t\t}";
+    const searchSpaces = "    if(effective_dir == BREAKOUT_UP)\n        {\n            // 向上突破\n        }";
+    const result = findActualString(fileContent, searchSpaces);
+    expect(result).not.toBeNull();
+    expect(result).toBe(fileContent);
+  });
+
+  // ── Returned string must be a valid substring of fileContent ──
+
+  test("returned string from tab match is a real substring of fileContent", () => {
+    const fileContent = "prefix\n\t\tindented code\nsuffix";
+    const searchSpaces = "prefix\n        indented code\nsuffix";
+    const result = findActualString(fileContent, searchSpaces);
+    expect(result).not.toBeNull();
+    expect(fileContent.includes(result!)).toBe(true);
+  });
+
+  test("returned string from partial tab match is a real substring", () => {
+    const fileContent = "line1\n\tif (x) {\n\t\tdoStuff();\n\t}\nline5";
+    const searchSpaces = "    if (x) {\n        doStuff();\n    }";
+    const result = findActualString(fileContent, searchSpaces);
+    expect(result).not.toBeNull();
+    expect(fileContent.includes(result!)).toBe(true);
+  });
+
+  test("tab match with mixed indentation levels", () => {
+    const fileContent = "class Foo {\n\t\tmethod1() {\n\t\t\treturn 42;\n\t\t}\n}";
+    const searchSpaces = "class Foo {\n        method1() {\n            return 42;\n        }\n}";
+    const result = findActualString(fileContent, searchSpaces);
+    expect(result).not.toBeNull();
+    expect(fileContent.includes(result!)).toBe(true);
+  });
 });
 
 // ─── preserveQuoteStyle ─────────────────────────────────────────────────
diff --git a/packages/builtin-tools/src/tools/FileEditTool/utils.ts b/packages/builtin-tools/src/tools/FileEditTool/utils.ts
index 6de429b34..2709ba423 100644
--- a/packages/builtin-tools/src/tools/FileEditTool/utils.ts
+++ b/packages/builtin-tools/src/tools/FileEditTool/utils.ts
@@ -63,9 +63,26 @@ export function stripTrailingWhitespace(str: string): string {
   return result
 }
 
+/**
+ * Normalizes whitespace for fuzzy matching by converting tabs to spaces
+ * and collapsing leading whitespace on each line to a canonical form.
+ * This handles the case where Read tool output renders tabs as spaces,
+ * so users copy spaces from the output but the file actually has tabs.
+ */
+function normalizeWhitespace(str: string): string {
+  return str.replace(/\t/g, '    ')
+}
+
 /**
  * Finds the actual string in the file content that matches the search string,
- * accounting for quote normalization
+ * accounting for quote normalization and tab/space differences.
+ *
+ * Matching cascade:
+ * 1. Exact match
+ * 2. Quote normalization (curly → straight quotes)
+ * 3. Tab/space normalization (tabs ↔ spaces in leading whitespace)
+ * 4. Quote + tab/space normalization combined
+ *
  * @param fileContent The file content to search in
  * @param searchString The string to search for
  * @returns The actual string found in the file, or null if not found
@@ -89,9 +106,92 @@ export function findActualString(
     return fileContent.substring(searchIndex, searchIndex + searchString.length)
   }
 
+  // Try with tab/space normalization — handles the case where Read output
+  // renders tabs as spaces and the user copies the rendered version
+  const wsNormalizedFile = normalizeWhitespace(fileContent)
+  const wsNormalizedSearch = normalizeWhitespace(searchString)
+
+  const wsSearchIndex = wsNormalizedFile.indexOf(wsNormalizedSearch)
+  if (wsSearchIndex !== -1) {
+    // Map the match position back to the original file content.
+    // We need to find the corresponding range in the original string.
+    return mapNormalizedMatchBackToFile(fileContent, wsNormalizedFile, wsSearchIndex, wsNormalizedSearch.length)
+  }
+
+  // Try combined: quote normalization + tab/space normalization
+  const combinedFile = normalizeWhitespace(normalizedFile)
+  const combinedSearch = normalizeWhitespace(normalizedSearch)
+
+  const combinedIndex = combinedFile.indexOf(combinedSearch)
+  if (combinedIndex !== -1) {
+    return mapNormalizedMatchBackToFile(fileContent, combinedFile, combinedIndex, combinedSearch.length)
+  }
+
   return null
 }
 
+/**
+ * Given a match found in a normalized version of fileContent, map the match
+ * position back to the original fileContent and extract the corresponding
+ * substring.
+ *
+ * Strategy: walk through both strings character by character, building a
+ * mapping from normalized offset to original offset. When a tab is expanded
+ * to 4 spaces in the normalized version, the normalized offset advances by 4
+ * while the original offset advances by 1.
+ */
+function mapNormalizedMatchBackToFile(
+  fileContent: string,
+  normalizedFile: string,
+  normalizedStart: number,
+  normalizedLength: number,
+): string {
+  // Build a sparse mapping from normalized position → original position.
+  // We only need to map the range [normalizedStart, normalizedStart + normalizedLength].
+  let normPos = 0
+  let origPos = 0
+  let origStart = -1
+  let origEnd = -1
+
+  while (origPos < fileContent.length && normPos <= normalizedStart + normalizedLength) {
+    if (normPos === normalizedStart) {
+      origStart = origPos
+    }
+    if (normPos === normalizedStart + normalizedLength) {
+      origEnd = origPos
+      break
+    }
+
+    const origChar = fileContent[origPos]!
+    if (origChar === '\t') {
+      // Tab expands to 4 spaces in normalized version
+      const nextNormPos = normPos + 4
+      // If normalizedStart falls within this expanded tab, snap to origPos
+      if (normPos < normalizedStart && nextNormPos > normalizedStart && origStart === -1) {
+        origStart = origPos
+      }
+      if (normPos < normalizedStart + normalizedLength && nextNormPos > normalizedStart + normalizedLength && origEnd === -1) {
+        origEnd = origPos + 1
+      }
+      normPos = nextNormPos
+      origPos++
+    } else {
+      normPos++
+      origPos++
+    }
+  }
+
+  // Fallback: if we couldn't map precisely, use character-count heuristic
+  if (origStart === -1) origStart = 0
+  if (origEnd === -1) {
+    // Approximate: use the ratio of original to normalized length
+    const ratio = fileContent.length / normalizedFile.length
+    origEnd = Math.round(origStart + normalizedLength * ratio)
+  }
+
+  return fileContent.substring(origStart, origEnd)
+}
+
 /**
  * When old_string matched via quote normalization (curly quotes in file,
  * straight quotes from model), apply the same curly quote style to new_string