fix: prompt_override 경로 _total_decisions 미카운트, 완료 로그 추가, 테스트 보완

리뷰 지적 사항 반영:
- _total_decisions 카운트 제거 (플레이북 생성은 거래 결정이 아님 → 메트릭 왜곡 방지)
- "Gemini raw response received" INFO 로그 추가 (완료 추적 가능)
- test_prompt_override_takes_priority_over_optimization 신규 추가
  (enable_optimization=True 상태에서도 prompt_override 우선됨을 검증)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/brain/gemini_client.py

@@ -441,6 +441,18 @@ class GeminiClient:
                 action="HOLD", confidence=0, rationale=f"API error: {exc}", token_count=token_count
             )
 
+        # prompt_override callers (e.g. pre_market_planner) expect raw text back,
+        # not a parsed TradeDecision. Skip parse_response to avoid spurious
+        # "Missing fields" warnings and return the raw response directly. (#247)
+        if "prompt_override" in market_data:
+            logger.info(
+                "Gemini raw response received (prompt_override, tokens=%d)", token_count
+            )
+            # Not a trade decision — don't inflate _total_decisions metrics
+            return TradeDecision(
+                action="HOLD", confidence=0, rationale=raw, token_count=token_count
+            )
+
         decision = self.parse_response(raw)
         self._total_decisions += 1
 

tests/test_brain.py

@@ -302,9 +302,10 @@ class TestPromptOverride:
         client = GeminiClient(settings)
 
         custom_prompt = "You are a playbook generator. Return JSON with scenarios."
+        playbook_json = '{"market_outlook": "neutral", "stocks": []}'
 
         mock_response = MagicMock()
-        mock_response.text = '{"action": "HOLD", "confidence": 50, "rationale": "test"}'
+        mock_response.text = playbook_json
 
         with patch.object(
             client._client.aio.models,
@@ -317,7 +318,7 @@ class TestPromptOverride:
                 "current_price": 0,
                 "prompt_override": custom_prompt,
             }
-            await client.decide(market_data)
+            decision = await client.decide(market_data)
 
             # Verify the custom prompt was sent, not a built prompt
             mock_generate.assert_called_once()
@@ -325,17 +326,50 @@ class TestPromptOverride:
                 "contents", mock_generate.call_args[0][1] if len(mock_generate.call_args[0]) > 1 else None
             )
             assert actual_prompt == custom_prompt
+            # Raw response preserved in rationale without parse_response (#247)
+            assert decision.rationale == playbook_json
 
     @pytest.mark.asyncio
-    async def test_prompt_override_skips_optimization(self, settings):
-        """prompt_override should bypass prompt optimization."""
+    async def test_prompt_override_skips_parse_response(self, settings):
+        """prompt_override bypasses parse_response — no Missing fields warning, raw preserved."""
         client = GeminiClient(settings)
         client._enable_optimization = True
 
         custom_prompt = "Custom playbook prompt"
+        playbook_json = '{"market_outlook": "bullish", "stocks": [{"stock_code": "AAPL"}]}'
 
         mock_response = MagicMock()
-        mock_response.text = '{"action": "HOLD", "confidence": 50, "rationale": "ok"}'
+        mock_response.text = playbook_json
+
+        with patch.object(
+            client._client.aio.models,
+            "generate_content",
+            new_callable=AsyncMock,
+            return_value=mock_response,
+        ):
+            with patch.object(client, "parse_response") as mock_parse:
+                market_data = {
+                    "stock_code": "PLANNER",
+                    "current_price": 0,
+                    "prompt_override": custom_prompt,
+                }
+                decision = await client.decide(market_data)
+
+                # parse_response must NOT be called for prompt_override
+                mock_parse.assert_not_called()
+                # Raw playbook JSON preserved in rationale
+                assert decision.rationale == playbook_json
+
+    @pytest.mark.asyncio
+    async def test_prompt_override_takes_priority_over_optimization(self, settings):
+        """prompt_override must win over enable_optimization=True."""
+        client = GeminiClient(settings)
+        client._enable_optimization = True
+
+        custom_prompt = "Explicit playbook prompt"
+
+        mock_response = MagicMock()
+        mock_response.text = '{"market_outlook": "neutral", "stocks": []}'
 
         with patch.object(
             client._client.aio.models,
@@ -353,6 +387,7 @@ class TestPromptOverride:
             actual_prompt = mock_generate.call_args[1].get(
                 "contents", mock_generate.call_args[0][1] if len(mock_generate.call_args[0]) > 1 else None
             )
+            # The custom prompt must be used, not the compressed prompt
             assert actual_prompt == custom_prompt
 
     @pytest.mark.asyncio