diff --git a/backend/app/services/report_agent.py b/backend/app/services/report_agent.py
index cecd70b464..88bff23a7f 100644
--- a/backend/app/services/report_agent.py
+++ b/backend/app/services/report_agent.py
@@ -664,6 +664,12 @@ def to_dict(self) -> Dict[str, Any]:
    - 不要添加模拟中不存在的信息
    - 如果某方面信息不足，如实说明
 
+5. 【禁止捏造数据】
+   - ❌ 禁止捏造用户名、引用、统计数字或互动数据
+   - ❌ 禁止在回复中包含 <tool_result> 块 — 只有系统会提供工具结果
+   - ✅ 只能引用真实出现在工具结果中的实体、引用和数据
+   - 如果工具结果中没有相关内容，应如实说明，而非编造
+
 ═══════════════════════════════════════════════════════════════
 【⚠️ 格式规范 - 极其重要！】
 ═══════════════════════════════════════════════════════════════
@@ -1133,7 +1139,26 @@ def _get_tools_description(self) -> str:
             if params_desc:
                 desc_parts.append(f"  参数: {params_desc}")
         return "\n".join(desc_parts)
-    
+
+    @staticmethod
+    def _strip_fake_tool_results(response: str) -> str:
+        """Strip any <tool_result> blocks the LLM fabricated in its response.
+
+        When the LLM generates a <tool_call> block and then continues to generate
+        a <tool_result> block in the same response, we must strip the fake result
+        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,
+        )
+        cleaned = re.sub(r'\n{3,}', '\n\n', cleaned)
+        return cleaned.strip()
+
     def plan_outline(
         self, 
         progress_callback: Optional[Callable] = None
@@ -1335,7 +1360,8 @@ def _generate_section_react(
 
                 if conflict_retries <= 2:
                     # 前两次：丢弃本次响应，要求 LLM 重新回复
-                    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": (
@@ -1375,7 +1401,8 @@ def _generate_section_react(
             if has_final_answer:
                 # 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:
-                    messages.append({"role": "assistant", "content": response})
+                    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 ""
                     messages.append({
@@ -1451,9 +1478,10 @@ def _generate_section_react(
                 unused_tools = all_tools - used_tools
                 unused_hint = ""
                 if unused_tools and tool_calls_count < self.MAX_TOOL_CALLS_PER_SECTION:
-                    unused_hint = REACT_UNUSED_TOOLS_HINT.format(unused_list="、".join(unused_tools))
+                    unlock_hint = REACT_UNUSED_TOOLS_HINT.format(unused_list="、".join(unused_tools))
 
-                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_OBSERVATION_TEMPLATE.format(
@@ -1857,7 +1885,8 @@ def chat(
                 tool_calls_made.append(call)
             
             # 将结果添加到消息
-            messages.append({"role": "assistant", "content": response})
+            cleaned_response = ReportAgent._strip_fake_tool_results(response)
+            messages.append({"role": "assistant", "content": cleaned_response})
             observation = "\n".join([f"[{r['tool']}结果]\n{r['result']}" for r in tool_results])
             messages.append({
                 "role": "user",
diff --git a/backend/pytest.ini b/backend/pytest.ini
new file mode 100644
index 0000000000..13bc1da95f
--- /dev/null
+++ b/backend/pytest.ini
@@ -0,0 +1,6 @@
+[pytest]
+testpaths = tests
+python_files = test_*.py
+python_classes = Test*
+python_functions = test_*
+addopts = -v --tb=short
\ No newline at end of file
diff --git a/backend/tests/__init__.py b/backend/tests/__init__.py
new file mode 100644
index 0000000000..eeac18e004
--- /dev/null
+++ b/backend/tests/__init__.py
@@ -0,0 +1 @@
+"""Tests package marker"""
\ No newline at end of file
diff --git a/backend/tests/test_file_parser.py b/backend/tests/test_file_parser.py
new file mode 100644
index 0000000000..41b268b3ff
--- /dev/null
+++ b/backend/tests/test_file_parser.py
@@ -0,0 +1,244 @@
+"""Unit tests for file_parser module."""
+
+import os
+import tempfile
+from pathlib import Path
+
+import pytest
+
+# Import the module directly to avoid Flask initialization issues
+import sys
+from pathlib import Path
+sys.path.insert(0, str(Path(__file__).parent.parent))
+
+# Direct import of the module to avoid app package initialization
+import importlib.util
+spec = importlib.util.spec_from_file_location(
+    "file_parser",
+    Path(__file__).parent.parent / "app" / "utils" / "file_parser.py"
+)
+file_parser_module = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(file_parser_module)
+
+_read_text_with_fallback = file_parser_module._read_text_with_fallback
+FileParser = file_parser_module.FileParser
+split_text_into_chunks = file_parser_module.split_text_into_chunks
+
+
+class TestReadTextWithFallback:
+    """Tests for _read_text_with_fallback function."""
+
+    def test_read_utf8_file(self):
+        """Should read UTF-8 encoded file correctly."""
+        with tempfile.NamedTemporaryFile(mode='w', encoding='utf-8', suffix='.txt', delete=False) as f:
+            f.write("Hello, 你好, こんにちは")
+            path = f.name
+        try:
+            result = _read_text_with_fallback(path)
+            assert result == "Hello, 你好, こんにちは"
+        finally:
+            os.unlink(path)
+
+    def test_read_gbk_file_with_fallback(self):
+        """Should read GBK encoded file using UTF-8 replacement when detection fails."""
+        with tempfile.NamedTemporaryFile(mode='wb', suffix='.txt', delete=False) as f:
+            content = "你好世界".encode('gbk')
+            f.write(content)
+            path = f.name
+        try:
+            result = _read_text_with_fallback(path)
+            # Result may be garbled if charset detection fails, but should not raise
+            assert len(result) > 0
+        finally:
+            os.unlink(path)
+
+    def test_read_latin1_file(self):
+        """Should read Latin-1 encoded file using UTF-8 replacement when detection fails."""
+        with tempfile.NamedTemporaryFile(mode='wb', suffix='.txt', delete=False) as f:
+            content = "Héllo Wörld".encode('latin-1')
+            f.write(content)
+            path = f.name
+        try:
+            result = _read_text_with_fallback(path)
+            # Result may be garbled if charset detection fails, but should not raise
+            assert len(result) > 0
+        finally:
+            os.unlink(path)
+
+    def test_read_file_with_replacement_chars(self):
+        """Should replace invalid characters instead of failing."""
+        with tempfile.NamedTemporaryFile(mode='wb', suffix='.txt', delete=False) as f:
+            content = b"Hello\x00\xff\xfeWorld"
+            f.write(content)
+            path = f.name
+        try:
+            result = _read_text_with_fallback(path)
+            assert "Hello" in result
+            assert "World" in result
+        finally:
+            os.unlink(path)
+
+
+class TestFileParser:
+    """Tests for FileParser class."""
+
+    def test_supported_extensions(self):
+        """Should have correct supported extensions."""
+        assert '.pdf' in FileParser.SUPPORTED_EXTENSIONS
+        assert '.md' in FileParser.SUPPORTED_EXTENSIONS
+        assert '.markdown' in FileParser.SUPPORTED_EXTENSIONS
+        assert '.txt' in FileParser.SUPPORTED_EXTENSIONS
+
+    def test_extract_text_from_nonexistent_file(self):
+        """Should raise FileNotFoundError for nonexistent file."""
+        with pytest.raises(FileNotFoundError):
+            FileParser.extract_text('/nonexistent/file.txt')
+
+    def test_extract_text_from_unsupported_format(self):
+        """Should raise ValueError for unsupported format."""
+        with tempfile.NamedTemporaryFile(suffix='.xyz', delete=False) as f:
+            path = f.name
+        try:
+            with pytest.raises(ValueError, match="不支持的文件格式"):
+                FileParser.extract_text(path)
+        finally:
+            os.unlink(path)
+
+    def test_extract_text_from_md_file(self):
+        """Should extract text from markdown file."""
+        with tempfile.NamedTemporaryFile(mode='w', encoding='utf-8', suffix='.md', delete=False) as f:
+            f.write("# Title\n\nThis is content.")
+            path = f.name
+        try:
+            result = FileParser.extract_text(path)
+            assert "# Title" in result
+            assert "This is content." in result
+        finally:
+            os.unlink(path)
+
+    def test_extract_text_from_txt_file(self):
+        """Should extract text from txt file."""
+        with tempfile.NamedTemporaryFile(mode='w', encoding='utf-8', suffix='.txt', delete=False) as f:
+            f.write("Plain text content")
+            path = f.name
+        try:
+            result = FileParser.extract_text(path)
+            assert result == "Plain text content"
+        finally:
+            os.unlink(path)
+
+    def test_extract_from_multiple_with_all_valid(self):
+        """Should extract from multiple valid files."""
+        files = []
+        try:
+            for i in range(3):
+                with tempfile.NamedTemporaryFile(mode='w', suffix='.txt', delete=False) as f:
+                    f.write(f"Content {i}")
+                    files.append(f.name)
+
+            result = FileParser.extract_from_multiple(files)
+            assert "Content 0" in result
+            assert "Content 1" in result
+            assert "Content 2" in result
+            assert "文档 1" in result
+            assert "文档 2" in result
+            assert "文档 3" in result
+        finally:
+            for path in files:
+                os.unlink(path)
+
+    def test_extract_from_multiple_with_invalid_file(self):
+        """Should handle invalid file gracefully in batch mode."""
+        files = [
+            '/nonexistent/path.txt',
+        ]
+        try:
+            with tempfile.NamedTemporaryFile(mode='w', suffix='.txt', delete=False) as f:
+                f.write("Valid content")
+                files.append(f.name)
+
+            result = FileParser.extract_from_multiple(files)
+            assert "Valid content" in result
+            assert "提取失败" in result
+        finally:
+            for path in files[1:]:
+                if os.path.exists(path):
+                    os.unlink(path)
+
+
+class TestSplitTextIntoChunks:
+    """Tests for split_text_into_chunks function."""
+
+    def test_short_text_returns_single_chunk(self):
+        """Should return single chunk when text is shorter than chunk_size."""
+        text = "Short text"
+        result = split_text_into_chunks(text, chunk_size=500, overlap=50)
+        assert len(result) == 1
+        assert result[0] == text
+
+    def test_empty_text_returns_empty_list(self):
+        """Should return empty list for empty/whitespace text."""
+        assert split_text_into_chunks("   ", chunk_size=500, overlap=50) == []
+        assert split_text_into_chunks("", chunk_size=500, overlap=50) == []
+
+    def test_text_exactly_at_chunk_size(self):
+        """Should return single chunk when text equals chunk_size."""
+        text = "a" * 500
+        result = split_text_into_chunks(text, chunk_size=500, overlap=50)
+        assert len(result) == 1
+
+    def test_long_text_splits_into_multiple_chunks(self):
+        """Should split long text into multiple chunks."""
+        text = "a" * 1000
+        result = split_text_into_chunks(text, chunk_size=500, overlap=50)
+        assert len(result) >= 2
+
+    def test_chunks_have_overlap(self):
+        """Should have overlapping content between consecutive chunks."""
+        text = "abcdefghij" * 100
+        chunks = split_text_into_chunks(text, chunk_size=100, overlap=20)
+        if len(chunks) >= 2:
+            assert chunks[0][-20:] == chunks[1][:20], "Chunks should overlap"
+
+    def test_chunks_preserve_content(self):
+        """Should preserve all original content across chunks."""
+        text = "".join(str(i) for i in range(500))
+        chunks = split_text_into_chunks(text, chunk_size=100, overlap=10)
+        combined = "".join(chunks)
+        assert text[:400] in combined or all(c in combined for c in text[:400])
+
+    def test_chunk_size_parameter(self):
+        """Should respect chunk_size parameter."""
+        text = "a" * 1000
+        result = split_text_into_chunks(text, chunk_size=100, overlap=0)
+        for chunk in result:
+            assert len(chunk) <= 100
+
+    def test_overlap_parameter(self):
+        """Should respect overlap parameter."""
+        text = "abcdefghij" * 100
+        chunks = split_text_into_chunks(text, chunk_size=50, overlap=10)
+        if len(chunks) >= 2:
+            overlap_size = len(chunks[0]) - (len(chunks[0].rstrip()) - len(chunks[1].lstrip()))
+            assert overlap_size >= 5
+
+    def test_split_at_sentence_boundary(self):
+        """Should try to split at sentence boundaries when possible."""
+        text = "第一句。第二句。第三句。" * 50
+        chunks = split_text_into_chunks(text, chunk_size=100, overlap=10)
+        for chunk in chunks:
+            if len(chunk) > 50:
+                assert chunk[-1] in "。.\n"
+
+    def test_last_chunk_may_be_smaller(self):
+        """Should allow last chunk to be smaller than chunk_size."""
+        text = "a" * 550
+        result = split_text_into_chunks(text, chunk_size=500, overlap=50)
+        assert any(len(chunk) < 500 for chunk in result)
+
+    def test_whitespace_only_chunks_filtered(self):
+        """Should filter out whitespace-only chunks."""
+        text = "content" + " " * 600 + "more content"
+        result = split_text_into_chunks(text, chunk_size=500, overlap=50)
+        for chunk in result:
+            assert chunk.strip()
\ No newline at end of file
diff --git a/backend/tests/test_locale.py b/backend/tests/test_locale.py
new file mode 100644
index 0000000000..ed5d38d9e1
--- /dev/null
+++ b/backend/tests/test_locale.py
@@ -0,0 +1,98 @@
+"""Unit tests for locale module."""
+
+import json
+from pathlib import Path
+
+import pytest
+
+
+def _load_locale_files():
+    """Load locale files for testing."""
+    # Construct absolute path to source/locales from this test file's location
+    # This test file is at: source/backend/tests/test_locale.py
+    # We need: source/locales/
+    this_file = Path(__file__).resolve()
+    # tests/test_locale.py -> tests/ -> backend/ -> source/
+    source_root = this_file.parent.parent.parent
+    locales_dir = source_root / "locales"
+
+    # Load languages.json
+    with open(locales_dir / "languages.json", "r", encoding="utf-8") as f:
+        languages = json.load(f)
+
+    # Load translations
+    translations = {}
+    for filename in Path(locales_dir).iterdir():
+        if filename.suffix == ".json" and filename.name != "languages.json":
+            locale_name = filename.stem
+            with open(filename, "r", encoding="utf-8") as f:
+                translations[locale_name] = json.load(f)
+
+    return languages, translations
+
+
+# Load locale data at module level for structure tests
+_languages, _translations = _load_locale_files()
+
+
+class TestLocaleStructure:
+    """Tests for locale file structure and completeness."""
+
+    def test_languages_has_required_fields(self):
+        """Should have required fields in languages.json."""
+        assert "zh" in _languages
+        assert "en" in _languages
+        assert _languages["zh"]["label"] == "中文"
+        assert _languages["en"]["label"] == "English"
+
+    def test_languages_have_llm_instruction(self):
+        """Should have llmInstruction field for each language."""
+        for lang, config in _languages.items():
+            assert "llmInstruction" in config
+            assert len(config["llmInstruction"]) > 0
+
+    def test_zh_translation_has_common_keys(self):
+        """zh translation should have common keys."""
+        zh = _translations.get("zh", {})
+        assert "common" in zh
+        assert "confirm" in zh["common"]
+        assert "cancel" in zh["common"]
+        assert "loading" in zh["common"]
+
+    def test_en_translation_has_common_keys(self):
+        """en translation should have common keys."""
+        en = _translations.get("en", {})
+        assert "common" in en
+        assert "confirm" in en["common"]
+        assert "cancel" in en["common"]
+        assert "loading" in en["common"]
+
+    def test_zh_and_en_have_same_top_level_keys(self):
+        """zh and en should have same top-level keys."""
+        zh_keys = set(_translations.get("zh", {}).keys())
+        en_keys = set(_translations.get("en", {}).keys())
+        # All en keys should be in zh, and vice versa
+        assert zh_keys == en_keys, "zh and en should have same top-level keys"
+
+    def test_translation_interpolation_format(self):
+        """Translations with variables should use {var} format."""
+        zh = _translations.get("zh", {})
+        # Check a known key with interpolation
+        if "home" in zh and "heroDesc" in zh["home"]:
+            hero_desc = zh["home"]["heroDesc"]
+            # Should contain {brand}, {agentScale}, {optimalSolution} placeholders
+            assert "{" in hero_desc, "heroDesc should have interpolation placeholders"
+
+
+class TestLanguagesCompleteness:
+    """Tests for language completeness."""
+
+    def test_translation_files_have_same_keys(self):
+        """All existing translation files should have the same structure."""
+        # Get keys from zh as reference
+        zh_keys = set(_translations.get("zh", {}).keys())
+        for lang, trans in _translations.items():
+            if lang != "zh":
+                trans_keys = set(trans.keys())
+                missing_in_trans = zh_keys - trans_keys
+                assert not missing_in_trans, f"{lang} missing keys: {missing_in_trans}"