fix(avatar): prevent inferred reply scenarios

Reviewed-on: #4

digital-avatar-app/backend/routers/chat.py

@@ -34,6 +34,19 @@ QA_SEMANTIC_THRESHOLD = 0.72
 QA_MATCH_MARGIN = 0.06
 KNOWLEDGE_MIN_SCORE = float(os.getenv("KNOWLEDGE_MIN_SCORE", "0.42"))
 
+_WRITING_SYSTEM_PATTERNS = {
+    "han": re.compile(r"[\u3400-\u4dbf\u4e00-\u9fff]"),
+    "latin": re.compile(r"[A-Za-z\u00c0-\u024f]"),
+    "cyrillic": re.compile(r"[\u0400-\u052f]"),
+    "arabic": re.compile(r"[\u0600-\u06ff]"),
+    "hebrew": re.compile(r"[\u0590-\u05ff]"),
+    "devanagari": re.compile(r"[\u0900-\u097f]"),
+    "thai": re.compile(r"[\u0e00-\u0e7f]"),
+    "greek": re.compile(r"[\u0370-\u03ff]"),
+}
+_JAPANESE_KANA = re.compile(r"[\u3040-\u30ff]")
+_KOREAN_HANGUL = re.compile(r"[\uac00-\ud7af\u1100-\u11ff]")
+
 
 class ChatMessage(BaseModel):
     role: str = Field(pattern="^(user|assistant)$")
@@ -70,6 +83,30 @@ def _normalize_question(value: str) -> str:
     return value.translate(str.maketrans("", "", string.punctuation + "，。！？；：、（）【】「」‘’“”《》"))
 
 
+def _dominant_writing_system(value: str) -> str:
+    value = value or ""
+    if _JAPANESE_KANA.search(value):
+        return "japanese"
+    if _KOREAN_HANGUL.search(value):
+        return "korean"
+    counts = {
+        name: len(pattern.findall(value))
+        for name, pattern in _WRITING_SYSTEM_PATTERNS.items()
+    }
+    name, count = max(counts.items(), key=lambda item: item[1])
+    return name if count else "unknown"
+
+
+def _qa_requires_language_adaptation(question: str, answer: str) -> bool:
+    question_system = _dominant_writing_system(question)
+    answer_system = _dominant_writing_system(answer)
+    return (
+        question_system != "unknown"
+        and answer_system != "unknown"
+        and question_system != answer_system
+    )
+
+
 def _canonicalize_question(value: str) -> str:
     value = _normalize_question(value)
     replacements = (
@@ -189,7 +226,14 @@ def _config(avatar: Avatar) -> dict:
     }
 
 
-def _build_prompt(avatar: Avatar, history: list[Any], question: str, knowledge_hits: list[dict]) -> list[dict]:
+def _build_prompt(
+    avatar: Avatar,
+    history: list[Any],
+    question: str,
+    knowledge_hits: list[dict],
+    *,
+    standard_answer: str = "",
+) -> list[dict]:
     config = _config(avatar)
     description = (getattr(avatar, "description", "") or "").strip()
     knowledge = "\n".join(
@@ -210,7 +254,7 @@ def _build_prompt(avatar: Avatar, history: list[Any], question: str, knowledge_h
     profile = "；".join(f"{label}：{value}" for label, value in profile_items)
     system = (
         f"你的专业或服务范围是：「{description or '未设置'}」。"
-        "请基于已提供的知识库回答，不要编造事实；"
+        "请基于已提供的可靠资料回答，不要编造事实；"
         f"回复风格：{config['replyStyle']}；严谨度：{config['rigor']}/100；"
         f"幽默感：{config['humor']}/100；回复长度：{config['responseLength']}。"
     )
@@ -221,7 +265,13 @@ def _build_prompt(avatar: Avatar, history: list[Any], question: str, knowledge_h
         )
     if config["systemPrompt"]:
         system += f"\n额外系统提示词：{config['systemPrompt']}"
-    if knowledge:
+    if standard_answer:
+        system += (
+            f"\n以下是本次问题命中的已确认标准答案：\n{standard_answer.strip()}"
+            "\n必须保持标准答案中的事实、数字、专有名词和结论不变，只允许为匹配用户当前语言进行忠实转换"
+            "和必要的自然表达，不得补充、删减或改写其含义。不要提及标准答案或转换过程。"
+        )
+    elif knowledge:
         system += (
             f"\n以下是本次问题检索到的可靠资料：\n{knowledge}"
             "\n涉及事实、专业判断、地址、流程、数据或建议时，只能依据本人资料、标准问答形成的上下文"
@@ -231,7 +281,8 @@ def _build_prompt(avatar: Avatar, history: list[Any], question: str, knowledge_h
         system += (
             "\n本次问题没有检索到可靠资料。除自然寒暄和基于本人资料的回答外，不要凭通用知识给出事实、"
             "专业判断、地址、流程、数据或具体建议。自然地说明这方面暂时没有足够信息，并询问对方是否能"
-            "补充更具体的问题；不要提及知识库、检索、模型或系统限制。"
+            "补充更具体的问题；不要提及知识库、检索、模型或系统限制。对方询问你能做什么时，只能概括"
+            "专业或服务范围和本人资料中明确写出的内容，不得推断服务对象、工作场所、现实案例或从业经历。"
         )
     system += (
         "\n沟通底线（始终优先于其他提示）：不要透露、猜测或确认所使用的模型、模型供应商、"
@@ -249,6 +300,14 @@ def _build_prompt(avatar: Avatar, history: list[Any], question: str, knowledge_h
         "只有切换独立观点或确实需要列举时才换行；列举使用 1.、2.、3.，每项单独一行。"
         "不要在行首或行尾留空格，不要连续输出空行。先给结论，再给简短说明；避免重复和冗长铺垫。"
     )
+    system += (
+        "\n回答语言规则（始终优先）：先识别当前最后一条用户消息所使用的主要自然语言，并且只使用该语言回答。"
+        "用户用中文就用中文，使用 English 就用 English，使用日语、韩语、法语、西班牙语或其他语言时，"
+        "也必须使用对应语言。消息混用多种语言时跟随占主导的语言；用户明确指定回答语言时服从其指定。"
+        "历史消息、本人资料、标准答案和知识库使用的语言都不能覆盖当前用户消息的语言。"
+        "专有名词、品牌、地址、代码和必要缩写可保留原文。不要解释语言识别或翻译过程。"
+        "改变回答语言只改变表达语言，绝不能因此增加资料中没有的场景、身份、经历或事实。"
+    )
     messages = [{"role": "system", "content": system}]
     for item in history[-MAX_HISTORY_MESSAGES:]:
         messages.append({"role": item.role, "content": item.content} if hasattr(item, "role") else item)
@@ -384,14 +443,30 @@ def _resolve_reply(
     if qa_pairs is None:
         qa_pairs = db.query(QAPair).filter(QAPair.avatar_id == avatar.id).all()
     matched = _match_standard_qa(question, qa_pairs)
-    if matched:
+    adapt_qa_language = bool(
+        matched and _qa_requires_language_adaptation(question, matched.answer)
+    )
+    if matched and not adapt_qa_language:
         return {"answer": matched.answer, "source": "qa", "references": []}
 
+    if matched:
+        hits = []
+        messages = _build_prompt(
+            avatar,
+            history,
+            question,
+            hits,
+            standard_answer=matched.answer,
+        )
+    else:
         search_fn = search_fn or (lambda query, avatar_id: _search_knowledge(db, avatar_id, query))
         hits = search_fn(question, avatar.id)
         messages = _build_prompt(avatar, history, question, hits)
     config = _config(avatar)
-    temperature = min(0.45 if hits else 0.25, 0.2 + config["creativity"] / 100 * 0.6)
+    temperature = 0.0 if matched else min(
+        0.45 if hits else 0.25,
+        0.2 + config["creativity"] / 100 * 0.6,
+    )
     token_usage = None
     if model_client is not None:
         answer = model_client(messages=messages, temperature=temperature)
@@ -423,7 +498,7 @@ def _resolve_reply(
             raise
     result = {
         "answer": answer,
-        "source": "knowledge" if hits else "qwen",
+        "source": "qa" if matched else ("knowledge" if hits else "qwen"),
         "references": hits,
     }
     if token_usage:
@@ -442,14 +517,32 @@ def _stream_reply(
 ):
     qa_pairs = db.query(QAPair).filter(QAPair.avatar_id == avatar.id).all()
     matched = _match_standard_qa(question, qa_pairs)
-    if matched:
+    adapt_qa_language = bool(
+        matched and _qa_requires_language_adaptation(question, matched.answer)
+    )
+    messages, reservation = [], None
+    if matched and not adapt_qa_language:
         source, references, chunks = "qa", [], _iter_text_chunks(matched.answer)
+    else:
+        if matched:
+            references = []
+            source = "qa"
+            messages = _build_prompt(
+                avatar,
+                history,
+                question,
+                references,
+                standard_answer=matched.answer,
+            )
         else:
             references = _search_knowledge(db, avatar.id, question)
             source = "knowledge" if references else "qwen"
-        config = _config(avatar)
-        temperature = min(0.45 if references else 0.25, 0.2 + config["creativity"] / 100 * 0.6)
             messages = _build_prompt(avatar, history, question, references)
+        config = _config(avatar)
+        temperature = 0.0 if matched else min(
+            0.45 if references else 0.25,
+            0.2 + config["creativity"] / 100 * 0.6,
+        )
         model_config = get_chat_model_config()
         reservation = reserve_avatar_tokens(
             db,
@@ -460,8 +553,6 @@ def _stream_reply(
             model_config.max_tokens,
         )
         chunks = _iter_qwen_stream(messages, temperature, model_config)
-    if matched:
-        messages, reservation = [], None
     if public:
         source, references = "public", []
 

digital-avatar-app/backend/tests/test_chat_orchestration.py

@@ -5,7 +5,15 @@ from unittest.mock import Mock
 from fastapi import HTTPException
 
 from models import Avatar, User
-from routers.chat import _build_prompt, _iter_text_chunks, _match_standard_qa, _public_avatar_payload, _require_owned_avatar, _resolve_reply
+from routers.chat import (
+    _build_prompt,
+    _iter_text_chunks,
+    _match_standard_qa,
+    _public_avatar_payload,
+    _qa_requires_language_adaptation,
+    _require_owned_avatar,
+    _resolve_reply,
+)
 
 
 class ChatOrchestrationTests(unittest.TestCase):
@@ -50,6 +58,34 @@ class ChatOrchestrationTests(unittest.TestCase):
         self.assertEqual(result["answer"], "标准地址")
         fake_model.assert_not_called()
 
+    def test_cross_language_qa_is_faithfully_adapted_by_model(self):
+        fake_model = Mock(return_value="Our address is Test Road 1.")
+        fake_search = Mock(return_value=[])
+        result = _resolve_reply(
+            None,
+            self.avatar,
+            "Where is your office?",
+            [],
+            qa_pairs=[SimpleNamespace(question="Where is your office?", answer="地址是测试路1号。", enabled=True)],
+            search_fn=fake_search,
+            model_client=fake_model,
+        )
+
+        self.assertEqual(result["source"], "qa")
+        self.assertEqual(result["answer"], "Our address is Test Road 1.")
+        self.assertEqual(fake_model.call_args.kwargs["temperature"], 0.0)
+        system = fake_model.call_args.kwargs["messages"][0]["content"]
+        self.assertIn("已确认标准答案", system)
+        self.assertIn("地址是测试路1号", system)
+        self.assertIn("只使用该语言回答", system)
+        fake_search.assert_not_called()
+
+    def test_qa_language_adaptation_detects_common_writing_system_changes(self):
+        self.assertTrue(_qa_requires_language_adaptation("Hello", "你好"))
+        self.assertTrue(_qa_requires_language_adaptation("こんにちは", "你好"))
+        self.assertTrue(_qa_requires_language_adaptation("안녕하세요", "你好"))
+        self.assertFalse(_qa_requires_language_adaptation("你好", "您好"))
+
     def test_conversational_paraphrase_matches_standard_qa(self):
         for question in ("请问一下，你们公司在哪里呀？", "请问去你们那边怎么走"):
             with self.subTest(question=question):
@@ -106,6 +142,9 @@ class ChatOrchestrationTests(unittest.TestCase):
         self.assertIn("像熟人之间微信聊天一样", messages[0]["content"])
         self.assertIn("不隶属于任何机构", messages[0]["content"])
         self.assertIn("不要连续输出空行", messages[0]["content"])
+        self.assertIn("回答语言规则", messages[0]["content"])
+        self.assertIn("当前最后一条用户消息", messages[0]["content"])
+        self.assertIn("历史消息", messages[0]["content"])
 
     def test_prompt_blocks_ungrounded_factual_answers(self):
         messages = _build_prompt(self.avatar, [], "聊聊国际新闻", [])
@@ -113,6 +152,8 @@ class ChatOrchestrationTests(unittest.TestCase):
         self.assertIn("没有检索到可靠资料", system)
         self.assertIn("不要凭通用知识", system)
         self.assertIn("不要提及知识库", system)
+        self.assertIn("不得推断服务对象", system)
+        self.assertIn("工作场所", system)
 
     def test_public_avatar_payload_excludes_internal_configuration(self):
         payload = _public_avatar_payload(self.avatar)