diff --git a/backend/app/services/report_agent.py b/backend/app/services/report_agent.py
index 88bff23a..1bb212b1 100644
--- a/backend/app/services/report_agent.py
+++ b/backend/app/services/report_agent.py
@@ -1149,13 +1149,27 @@ class ReportAgent:
         before appending to message history. The real tool result will be injected
         separately by the system.
         """
-        import re
-        cleaned = re.sub(
-            r'<tool_result>.*?</tool_result>',
-            '',
-            response,
-            flags=re.DOTALL,
-        )
+        tag_pattern = re.compile(r'</?tool_result\b[^>]*>', flags=re.IGNORECASE)
+        parts = []
+        cursor = 0
+        depth = 0
+
+        for match in tag_pattern.finditer(response):
+            if depth == 0:
+                parts.append(response[cursor:match.start()])
+
+            if match.group(0).lstrip().startswith('</'):
+                depth = max(0, depth - 1)
+            else:
+                depth += 1
+            cursor = match.end()
+
+        if depth == 0:
+            parts.append(response[cursor:])
+
+        cleaned = ''.join(parts)
+        # Treat a malformed opening tag without a closing `>` as unsafe too.
+        cleaned = re.sub(r'<tool_result\b.*$', '', cleaned, flags=re.IGNORECASE | re.DOTALL)
         cleaned = re.sub(r'\n{3,}', '\n\n', cleaned)
         return cleaned.strip()
 
@@ -1399,9 +1413,9 @@ class ReportAgent:
 
             # ── 情况1：LLM 输出了 Final Answer ──
             if has_final_answer:
+                cleaned_response = ReportAgent._strip_fake_tool_results(response)
                 # 工具调用次数不足，拒绝并要求继续调工具
                 if tool_calls_count < min_tool_calls:
-                    cleaned_response = ReportAgent._strip_fake_tool_results(response)
                     messages.append({"role": "assistant", "content": cleaned_response})
                     unused_tools = all_tools - used_tools
                     unused_hint = f"（这些工具还未使用，推荐用一下他们: {', '.join(unused_tools)}）" if unused_tools else ""
@@ -1416,7 +1430,7 @@ class ReportAgent:
                     continue
 
                 # 正常结束
-                final_answer = response.split("Final Answer:")[-1].strip()
+                final_answer = cleaned_response.split("Final Answer:")[-1].strip()
                 logger.info(t('report.sectionGenDone', title=section.title, count=tool_calls_count))
 
                 if self.report_logger:
@@ -1432,7 +1446,8 @@ class ReportAgent:
             if has_tool_calls:
                 # 工具额度已耗尽 → 明确告知，要求输出 Final Answer
                 if tool_calls_count >= self.MAX_TOOL_CALLS_PER_SECTION:
-                    messages.append({"role": "assistant", "content": response})
+                    cleaned_response = ReportAgent._strip_fake_tool_results(response)
+                    messages.append({"role": "assistant", "content": cleaned_response})
                     messages.append({
                         "role": "user",
                         "content": REACT_TOOL_LIMIT_MSG.format(
@@ -1478,7 +1493,7 @@ class ReportAgent:
                 unused_tools = all_tools - used_tools
                 unused_hint = ""
                 if unused_tools and tool_calls_count < self.MAX_TOOL_CALLS_PER_SECTION:
-                    unlock_hint = REACT_UNUSED_TOOLS_HINT.format(unused_list="、".join(unused_tools))
+                    unused_hint = REACT_UNUSED_TOOLS_HINT.format(unused_list="、".join(unused_tools))
 
                 cleaned_response = ReportAgent._strip_fake_tool_results(response)
                 messages.append({"role": "assistant", "content": cleaned_response})
@@ -1496,7 +1511,8 @@ class ReportAgent:
                 continue
 
             # ── 情况3：既没有工具调用，也没有 Final Answer ──
-            messages.append({"role": "assistant", "content": response})
+            cleaned_response = ReportAgent._strip_fake_tool_results(response)
+            messages.append({"role": "assistant", "content": cleaned_response})
 
             if tool_calls_count < min_tool_calls:
                 # 工具调用次数不足，推荐未用过的工具
@@ -1516,7 +1532,7 @@ class ReportAgent:
             # 工具调用已足够，LLM 输出了内容但没带 "Final Answer:" 前缀
             # 直接将这段内容作为最终答案，不再空转
             logger.info(t('report.sectionNoPrefix', title=section.title, count=tool_calls_count))
-            final_answer = response.strip()
+            final_answer = cleaned_response
 
             if self.report_logger:
                 self.report_logger.log_section_content(
@@ -1865,6 +1881,7 @@ class ReportAgent:
                 # 没有工具调用，直接返回响应
                 clean_response = re.sub(r'<tool_call>.*?</tool_call>', '', response, flags=re.DOTALL)
                 clean_response = re.sub(r'\[TOOL_CALL\].*?\)', '', clean_response)
+                clean_response = ReportAgent._strip_fake_tool_results(clean_response)
                 
                 return {
                     "response": clean_response.strip(),
@@ -1902,6 +1919,7 @@ class ReportAgent:
         # 清理响应
         clean_response = re.sub(r'<tool_call>.*?</tool_call>', '', final_response, flags=re.DOTALL)
         clean_response = re.sub(r'\[TOOL_CALL\].*?\)', '', clean_response)
+        clean_response = ReportAgent._strip_fake_tool_results(clean_response)
         
         return {
             "response": clean_response.strip(),
diff --git a/backend/tests/test_report_tool_result_sanitizer.py b/backend/tests/test_report_tool_result_sanitizer.py
new file mode 100644
index 00000000..0a79cdc1
--- /dev/null
+++ b/backend/tests/test_report_tool_result_sanitizer.py
@@ -0,0 +1,28 @@
+import pytest
+
+from app.services.report_agent import ReportAgent
+
+
+@pytest.mark.parametrize(
+    ("response", "expected"),
+    [
+        ("before <tool_result>fake</tool_result> after", "before  after"),
+        ("before\n<tool_result>line 1\nline 2</tool_result>\nafter", "before\n\nafter"),
+        ("a<TOOL_RESULT source='model'>fake</TOOL_RESULT>b", "ab"),
+        (
+            "a<tool_result>outer<tool_result>inner</tool_result>end</tool_result>b",
+            "ab",
+        ),
+        ("safe<tool_result>unclosed fake", "safe"),
+        ("safe<tool_result malformed", "safe"),
+        ("a</tool_result>b", "ab"),
+    ],
+)
+def test_strip_fake_tool_results(response, expected):
+    assert ReportAgent._strip_fake_tool_results(response) == expected
+
+
+def test_preserves_legitimate_text_without_tool_result_tags():
+    response = "Final Answer: <tool_call>{}</tool_call> legitimate text"
+
+    assert ReportAgent._strip_fake_tool_results(response) == response