fix(review): apply code review fixes from ce-code-review

- P1: Use _resolve_execution_mode() instead of hardcoding SKILL_REACT
  in semantic_low_complexity, semantic_high, and merged_llm paths
- P1: QualityGate escalation uses name-based check (c.name) instead
  of identity check (c is) for robustness
- P2: Remove tautological complexity >= 0.3 in short_text_llm_hint
- P2: Add empty query guard in SemanticRouter.route()
- P2: Upgrade debug → warning log level for low-complexity fallback errors
- P2: Validate skill_hint against _SKILL_NAME_RE in _classify_merged
- P2: Rename has_high_signal → has_non_low_signal for clarity

src/agentkit/chat/semantic_router.py

@@ -178,6 +178,9 @@ class SemanticRouter:
         if self._index.size == 0:
             return SemanticRouteResult(confidence="low", skill_name=None, similarity=0.0)
 
+        if not query or not query.strip():
+            return SemanticRouteResult(confidence="low", skill_name=None, similarity=0.0)
+
         try:
             # Get query embedding (with cache)
             query_embedding = self._query_cache.get(query)

src/agentkit/chat/skill_routing.py

@@ -643,10 +643,10 @@ class HeuristicClassifier:
             self._MEDIUM_EXACT_RE.findall(content)
         )
 
-        has_high_signal = high_hits > 0 or medium_hits > 0
+        has_non_low_signal = high_hits > 0 or medium_hits > 0
 
         # 低复杂度信号仅在无高/中复杂度信号时生效
-        if has_low_signal and not has_high_signal:
+        if has_low_signal and not has_non_low_signal:
             score = 0.05  # 问候/闲聊直接给极低分
             length = len(content)
             if length > 200:
@@ -853,8 +853,11 @@ class CostAwareRouter:
             merged_complexity = max(0.0, min(1.0, merged_complexity))
             skill_hint = data.get("skill_hint")
 
-            # If skill_hint provided and valid, route directly to that skill
+            # Validate skill_hint against name pattern before lookup
             if skill_hint and skill_registry:
+                if not _SKILL_NAME_RE.match(str(skill_hint).strip().lower()):
+                    logger.warning(f"Invalid skill_hint from LLM: {skill_hint!r}")
+                    skill_hint = None
                 try:
                     matched_skill = skill_registry.get(skill_hint)
                     result = SkillRoutingResult(
@@ -866,7 +869,7 @@ class CostAwareRouter:
                         match_method="merged_llm",
                         match_confidence=0.7,
                         complexity=merged_complexity,
-                        execution_mode=ExecutionMode.SKILL_REACT,
+                        execution_mode=_resolve_execution_mode(matched_skill.config),
                     )
                     # Merge tools
                     agent_tools = (
@@ -1355,14 +1358,14 @@ class CostAwareRouter:
                             result.match_confidence = semantic_result.similarity
                             result.complexity = complexity
                             if result.matched:
-                                result.execution_mode = ExecutionMode.SKILL_REACT
+                                result.execution_mode = _resolve_execution_mode(result.skill_config)
                             result.execution_trace = trace if transparency != "SILENT" else []
                             result.transparency_level = transparency
                             span.set_attribute("route.layer", "semantic_low_complexity")
                             span.set_attribute("route.target", result.skill_name or "default")
                             return result
                     except Exception as e:
-                        logger.debug(f"Semantic routing for low-complexity query failed: {e}")
+                        logger.warning(f"Semantic routing for low-complexity query failed: {e}")
 
                 # Try IntentRouter keyword match before falling back to direct chat
                 # Low-complexity queries like "翻译这段话" should still match skills
@@ -1396,7 +1399,7 @@ class CostAwareRouter:
                             span.set_attribute("route.target", result.skill_name or "default")
                             return result
                     except Exception as e:
-                        logger.debug(f"Intent routing for low-complexity query failed: {e}")
+                        logger.warning(f"Intent routing for low-complexity query failed: {e}")
 
                 # No semantic or intent match → direct chat
                 result = SkillRoutingResult(
@@ -1457,7 +1460,7 @@ class CostAwareRouter:
                         result.match_confidence = semantic_result.similarity
                         result.complexity = complexity
                         if result.matched:
-                            result.execution_mode = ExecutionMode.SKILL_REACT
+                            result.execution_mode = _resolve_execution_mode(result.skill_config)
                         result.execution_trace = trace if transparency != "SILENT" else []
                         result.transparency_level = transparency
                         span.set_attribute("route.layer", "semantic_high")
@@ -1490,7 +1493,6 @@ class CostAwareRouter:
             if (
                 skill_hint is None
                 and len(clean_content) < 20
-                and complexity >= 0.3
                 and self._merged_llm_classify
                 and self._llm_gateway is not None
             ):

src/agentkit/quality/gate.py

@@ -126,12 +126,12 @@ class QualityGate:
             and skill_match_check.message
             and "Warning" in skill_match_check.message
         ):
-            other_failed = any(not c.passed for c in checks if c is not skill_match_check)
+            other_failed = any(not c.passed for c in checks if c.name != "skill_match")
             if other_failed:
                 # 升级：将 skill_match 的 passed 也设为 False
                 checks = [
                     QualityCheck(name=c.name, passed=False, message=c.message)
-                    if c is skill_match_check
+                    if c.name == "skill_match"
                     else c
                     for c in checks
                 ]