fix(session): 剔除 Session 标题中的 System Instruction 噪声; (#246)

Claude Code 会在首条 user 消息 content 中拼接多个 <system-reminder> /
<user-preferences> 等系统注入块,导致原 _extract_session_title 抽取出的
标题在不同会话间高度同质,丧失辨识度。

- 新增 _sanitize_user_text,基于白名单剥离 system-reminder、user-preferences、
  local-command-stdout/stderr、bash-input/stdout/stderr、ide_selection、
  stdin、system_instruction 等 CC 注入标签,折叠空白后返回真实用户输入;
- 优先识别 slash command (<command-name>/<command-args>),合成"命令 + 参数"
  式标题,避免命令式会话标题为空;
- 重写 _extract_session_title,跳过清洗后为空的 user 文本 part,自动 fallback
  到下一个有真实内容的 part;
- 补充 20 个单元测试覆盖噪声剥离、slash command、空白折叠、截断、边界场景。

🤖 Generated with [Claude Code](https://github.com/claude), [CodeX](https://openai.com), [Gemini](https://github.com/apps/gemini-code-assist)

Author: ThreeFish-AI

src/coding/proxy/routing/executor.py

@@ -7,6 +7,7 @@
 from __future__ import annotations
 
 import logging
+import re
 import time
 from collections.abc import AsyncIterator
 from typing import Any
@@ -54,16 +55,71 @@
 
 _SESSION_TITLE_MAX_LEN = 30
 
+# Claude Code 注入的"噪声"标签 — 系统级上下文,不应进入 Session 标题。
+# 这些标签由 CC harness 在首个 user 消息 content 中拼接,高度同质,
+# 直接用作标题会导致跨会话标题无差异化,丧失辨识度。
+_NOISE_TAG_PATTERN = re.compile(
+    r"<(?P<tag>system-reminder|user-preferences|"
+    r"local-command-stdout|local-command-stderr|"
+    r"bash-input|bash-stdout|bash-stderr|"
+    r"ide_selection|stdin|system_instruction)\b[^>]*>"
+    r".*?</(?P=tag)>",
+    flags=re.DOTALL | re.IGNORECASE,
+)
+
+# Slash command 子标签:用于识别 /commit、/review 等命令式调用,
+# 合成"命令 + 参数"式标题。
+_CMD_NAME_PATTERN = re.compile(r"<command-name>(.*?)</command-name>", flags=re.DOTALL)
+_CMD_ARGS_PATTERN = re.compile(r"<command-args>(.*?)</command-args>", flags=re.DOTALL)
+# 残留 command-* 包裹标签清除(command-message/command-stdout 等次要标签)。
+_CMD_WRAPPER_PATTERN = re.compile(
+    r"<command-[\w-]+>.*?</command-[\w-]+>", flags=re.DOTALL
+)
+
+
+def _sanitize_user_text(raw: str) -> str:
+    """剔除 Claude Code 注入的系统级 XML 块,还原真实用户输入。
+
+    处理顺序:
+    1. Slash command 优先识别 — 若检测到 <command-name>,合成"命令 + 参数"
+       式标题(因为残留文本通常为空,直接取标签内容更有意义)。
+    2. 通用噪声剥离 — 移除已知白名单内的 system-reminder 等标签。
+    3. 残留 command-* 包裹清除 — 兜底去除 command-message 等次要标签。
+    4. 前后空白归一化 — 折叠连续空白为单空格,便于 30 字截断。
+    """
+    if not raw:
+        return ""
+
+    # 阶段一: slash command 短路
+    cmd = _CMD_NAME_PATTERN.search(raw)
+    if cmd:
+        name = cmd.group(1).strip()
+        args_match = _CMD_ARGS_PATTERN.search(raw)
+        args = args_match.group(1).strip() if args_match else ""
+        composed = f"{name} {args}".strip() if args else name
+        if composed:
+            return composed
+
+    # 阶段二: 通用噪声剥离
+    cleaned = _NOISE_TAG_PATTERN.sub("", raw)
+    cleaned = _CMD_WRAPPER_PATTERN.sub("", cleaned)
+
+    # 阶段三: 空白折叠
+    return re.sub(r"\s+", " ", cleaned).strip()
+
 
 def _extract_session_title(request: CanonicalRequest) -> str:
-    """从规范化请求中提取首个用户消息文本作为 session 标题."""
+    """从规范化请求中提取首个用户消息文本作为 session 标题。
+
+    跳过 Claude Code 注入的系统级 XML 块(system-reminder、user-preferences 等),
+    确保标题反映用户真实输入而非高同质化的系统模板。
+    """
     for part in request.messages:
-        if (
-            part.role == "user"
-            and part.type == CanonicalPartType.TEXT
-            and part.text.strip()
-        ):
-            return part.text.strip()[:_SESSION_TITLE_MAX_LEN]
+        if part.role != "user" or part.type != CanonicalPartType.TEXT:
+            continue
+        cleaned = _sanitize_user_text(part.text)
+        if cleaned:
+            return cleaned[:_SESSION_TITLE_MAX_LEN]
     return ""
 
 

tests/test_router_executor.py

@@ -20,11 +20,14 @@
     build_canonical_request,
 )
 from coding.proxy.routing.executor import (
+    _SESSION_TITLE_MAX_LEN,
     _VENDOR_PROTOCOL_LABEL_MAP,
+    _extract_session_title,
     _has_tool_results,
     _is_likely_request_format_error,
     _log_vendor_response_error,
     _RouteExecutor,
+    _sanitize_user_text,
 )
 from coding.proxy.routing.session_manager import RouteSessionManager
 from coding.proxy.routing.tier import VendorTier
@@ -1949,3 +1952,162 @@ def test_returns_body_for_unknown_tier(self):
         result = exec_inst._prepare_body_for_tier(body, tier, source_vendor="zhipu")
 
         assert result is body
+
+
+# ── Session 标题清洗与抽取测试 ─────────────────────────────────
+
+
+class TestSanitizeUserText:
+    """``_sanitize_user_text`` — 剥离 CC 注入的系统级 XML 块.
+
+    覆盖典型 system-reminder/user-preferences 噪声、slash command
+    短路、空白折叠与边界场景。
+    """
+
+    def test_strips_system_reminder(self):
+        raw = "<system-reminder>MCP 指令</system-reminder>这是用户真实输入"
+        assert _sanitize_user_text(raw) == "这是用户真实输入"
+
+    def test_strips_user_preferences(self):
+        raw = "用户问题<user-preferences>遵循 AGENTS.md</user-preferences>"
+        assert _sanitize_user_text(raw) == "用户问题"
+
+    def test_strips_multiple_noise_blocks(self):
+        raw = (
+            "<system-reminder>A</system-reminder>"
+            "<system-reminder>B</system-reminder>"
+            "<system-reminder>C</system-reminder>"
+            "<system-reminder>D</system-reminder>"
+            "真实输入文本"
+            "<user-preferences>P</user-preferences>"
+        )
+        assert _sanitize_user_text(raw) == "真实输入文本"
+
+    def test_strips_multiline_system_reminder(self):
+        """多行 system-reminder 块需被 DOTALL 完整匹配剥离."""
+        raw = (
+            "<system-reminder>\n"
+            "# MCP Server Instructions\n"
+            "Use this server to fetch ...\n"
+            "</system-reminder>\n"
+            "TITLE 中的 Session 标题应当取自用户输入"
+        )
+        assert _sanitize_user_text(raw) == "TITLE 中的 Session 标题应当取自用户输入"
+
+    def test_strips_tag_with_attributes(self):
+        """容忍标签携带属性(如 <system-reminder type="x">)."""
+        raw = '<system-reminder type="x">noise</system-reminder>真实'
+        assert _sanitize_user_text(raw) == "真实"
+
+    def test_slash_command_with_args(self):
+        raw = (
+            "<command-message>commit (user)</command-message>"
+            "<command-name>/commit</command-name>"
+            "<command-args>修复标题</command-args>"
+        )
+        assert _sanitize_user_text(raw) == "/commit 修复标题"
+
+    def test_slash_command_no_args(self):
+        raw = "<command-name>/review</command-name>"
+        assert _sanitize_user_text(raw) == "/review"
+
+    def test_collapses_whitespace(self):
+        raw = "<system-reminder>X</system-reminder>\n\n   多余  空白\t\t折叠   "
+        assert _sanitize_user_text(raw) == "多余 空白 折叠"
+
+    def test_empty_after_strip(self):
+        raw = "<system-reminder>仅噪声</system-reminder>"
+        assert _sanitize_user_text(raw) == ""
+
+    def test_empty_input(self):
+        assert _sanitize_user_text("") == ""
+
+    def test_preserves_user_xml_like_content(self):
+        """用户输入中合法的 XML/HTML 片段(非白名单标签)需完整保留."""
+        raw = "请帮我审查这段代码:<div>hello</div> 是否符合规范?"
+        assert _sanitize_user_text(raw) == raw
+
+    def test_strips_local_command_output(self):
+        raw = "<local-command-stdout>build ok</local-command-stdout>构建后的下一步问题"
+        assert _sanitize_user_text(raw) == "构建后的下一步问题"
+
+
+class TestExtractSessionTitle:
+    """``_extract_session_title`` — 端到端从 CanonicalRequest 抽取标题."""
+
+    @staticmethod
+    def _build_request(messages: list[dict]):
+        return build_canonical_request({"model": "test", "messages": messages}, {})
+
+    def test_truncates_to_max_len(self):
+        long_text = "用户输入文本" * 20
+        req = self._build_request([{"role": "user", "content": long_text}])
+        title = _extract_session_title(req)
+        assert len(title) == _SESSION_TITLE_MAX_LEN
+        assert title == long_text[:_SESSION_TITLE_MAX_LEN]
+
+    def test_strips_noise_from_first_user_message(self):
+        raw = (
+            "<system-reminder>MCP 指令</system-reminder>"
+            "<user-preferences>偏好</user-preferences>"
+            "测试标题 ABC"
+        )
+        req = self._build_request([{"role": "user", "content": raw}])
+        assert _extract_session_title(req) == "测试标题 ABC"
+
+    def test_handles_real_cc_first_message_shape(self):
+        """模拟 CC 真实首条消息(多个连续 system-reminder + 用户文本)."""
+        raw = (
+            "<system-reminder>\n# MCP Server Instructions\n...</system-reminder>"
+            "<system-reminder>\nThe following skills...\n</system-reminder>"
+            "<system-reminder>\nPlan mode is active...\n</system-reminder>"
+            "\n\nTITLE 中的 Session 标题应当取自用户输入的信息前 30 个字\n\n"
+            "<user-preferences>始终遵循 AGENTS.md</user-preferences>"
+        )
+        req = self._build_request([{"role": "user", "content": raw}])
+        title = _extract_session_title(req)
+        assert title.startswith("TITLE 中的 Session")
+        assert len(title) <= _SESSION_TITLE_MAX_LEN
+
+    def test_extracts_slash_command(self):
+        raw = (
+            "<command-name>/commit</command-name>"
+            "<command-args>feat: 新增标题清洗</command-args>"
+        )
+        req = self._build_request([{"role": "user", "content": raw}])
+        assert _extract_session_title(req) == "/commit feat: 新增标题清洗"
+
+    def test_returns_empty_when_only_noise(self):
+        raw = "<system-reminder>纯噪声</system-reminder>"
+        req = self._build_request([{"role": "user", "content": raw}])
+        assert _extract_session_title(req) == ""
+
+    def test_returns_empty_for_no_user_messages(self):
+        req = self._build_request([{"role": "assistant", "content": "你好"}])
+        assert _extract_session_title(req) == ""
+
+    def test_skips_noise_only_part_to_find_real_input(self):
+        """首个 user text part 全噪声时,fallback 到下一个非空 user part."""
+        messages = [
+            {
+                "role": "user",
+                "content": [
+                    {
+                        "type": "text",
+                        "text": "<system-reminder>noise</system-reminder>",
+                    },
+                    {"type": "text", "text": "真实问题"},
+                ],
+            }
+        ]
+        req = self._build_request(messages)
+        assert _extract_session_title(req) == "真实问题"
+
+    def test_skips_assistant_role(self):
+        """assistant 角色的文本不应被作为标题候选."""
+        messages = [
+            {"role": "assistant", "content": "上一轮回答"},
+            {"role": "user", "content": "新的用户问题"},
+        ]
+        req = self._build_request(messages)
+        assert _extract_session_title(req) == "新的用户问题"