fix: SELL 주문에서 Fat Finger 오탐 수정 — 손절/익절 차단 버그 (#187)

SELL 주문은 현금을 소비하지 않고 받는 것이므로 Fat Finger 체크 대상이
아님. 포지션 가치가 잔여 현금의 30%를 초과해도 SELL은 정상 실행돼야 함.

- realtime/daily 사이클 두 곳 모두 수정
- SELL: check_circuit_breaker만 호출 (Fat Finger 스킵)
- BUY: 기존대로 validate_order 호출 (Fat Finger + Circuit Breaker)
- 테스트 2개 추가: SELL Fat Finger 스킵, SELL 서킷브레이커 적용 확인

재현 사례 (2026-02-21):
  JELD stop-loss -6.20% → FAT FINGER: 49,548 is 99.1% of cash 50,000
  RXT take-profit +46.13% → FAT FINGER: 88,676 is 177.4% of cash 50,000

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

src/analysis/smart_scanner.py

@@ -175,7 +175,7 @@ class SmartVolatilityScanner:
                 liquidity_score = volume_rank_bonus.get(stock_code, 0.0)
                 score = min(100.0, volatility_score + liquidity_score)
                 signal = "momentum" if change_rate >= 0 else "oversold"
-                implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 4.0)))
+                implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 2.0)))
 
                 candidates.append(
                     ScanCandidate(
@@ -282,7 +282,7 @@ class SmartVolatilityScanner:
             liquidity_score = volume_rank_bonus.get(stock_code, 0.0)
             score = min(100.0, volatility_score + liquidity_score)
             signal = "momentum" if change_rate >= 0 else "oversold"
-            implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 4.0)))
+            implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 2.0)))
             candidates.append(
                 ScanCandidate(
                     stock_code=stock_code,
@@ -338,7 +338,7 @@ class SmartVolatilityScanner:
 
                 score = min(volatility_pct / 10.0, 1.0) * 100.0
                 signal = "momentum" if change_rate >= 0 else "oversold"
-                implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 4.0)))
+                implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 2.0)))
                 candidates.append(
                     ScanCandidate(
                         stock_code=stock_code,

src/main.py

@@ -660,12 +660,17 @@ async def trading_cycle(
                 return
 
         # 5a. Risk check BEFORE order
+        # SELL orders do not consume cash (they receive it), so fat-finger check
+        # is skipped for SELLs — only circuit breaker applies.
         try:
-            risk.validate_order(
-                current_pnl_pct=pnl_pct,
-                order_amount=order_amount,
-                total_cash=total_cash,
-            )
+            if decision.action == "SELL":
+                risk.check_circuit_breaker(pnl_pct)
+            else:
+                risk.validate_order(
+                    current_pnl_pct=pnl_pct,
+                    order_amount=order_amount,
+                    total_cash=total_cash,
+                )
         except FatFingerRejected as exc:
             try:
                 await telegram.notify_fat_finger(
@@ -1123,12 +1128,17 @@ async def run_daily_session(
                         continue
 
                 # Risk check
+                # SELL orders do not consume cash (they receive it), so fat-finger
+                # check is skipped for SELLs — only circuit breaker applies.
                 try:
-                    risk.validate_order(
-                        current_pnl_pct=pnl_pct,
-                        order_amount=order_amount,
-                        total_cash=total_cash,
-                    )
+                    if decision.action == "SELL":
+                        risk.check_circuit_breaker(pnl_pct)
+                    else:
+                        risk.validate_order(
+                            current_pnl_pct=pnl_pct,
+                            order_amount=order_amount,
+                            total_cash=total_cash,
+                        )
                 except FatFingerRejected as exc:
                     try:
                         await telegram.notify_fat_finger(

tests/test_main.py

@@ -631,6 +631,119 @@ class TestTradingCycleTelegramIntegration:
         # Verify no trade notification sent
         mock_telegram.notify_trade_execution.assert_not_called()
 
+    @pytest.mark.asyncio
+    async def test_sell_skips_fat_finger_check(
+        self,
+        mock_broker: MagicMock,
+        mock_overseas_broker: MagicMock,
+        mock_scenario_engine: MagicMock,
+        mock_playbook: DayPlaybook,
+        mock_risk: MagicMock,
+        mock_db: MagicMock,
+        mock_decision_logger: MagicMock,
+        mock_context_store: MagicMock,
+        mock_criticality_assessor: MagicMock,
+        mock_telegram: MagicMock,
+        mock_market: MagicMock,
+    ) -> None:
+        """SELL orders must not be blocked by fat-finger check.
+
+        Even if position value > 30% of cash (e.g. stop-loss on a large holding
+        with low remaining cash), the SELL should proceed — only circuit breaker
+        applies to SELLs.
+        """
+        # SELL decision with held qty=100 shares @ 50,000 = 5,000,000
+        # cash = 5,000,000 → ratio = 100% which would normally trigger fat finger
+        mock_scenario_engine.evaluate = MagicMock(return_value=_make_sell_match())
+        mock_broker.get_balance = AsyncMock(
+            return_value={
+                "output1": [{"pdno": "005930", "ord_psbl_qty": "100"}],
+                "output2": [
+                    {
+                        "tot_evlu_amt": "10000000",
+                        "dnca_tot_amt": "5000000",
+                        "pchs_amt_smtl_amt": "5000000",
+                    }
+                ],
+            }
+        )
+
+        with patch("src.main.log_trade"):
+            await trading_cycle(
+                broker=mock_broker,
+                overseas_broker=mock_overseas_broker,
+                scenario_engine=mock_scenario_engine,
+                playbook=mock_playbook,
+                risk=mock_risk,
+                db_conn=mock_db,
+                decision_logger=mock_decision_logger,
+                context_store=mock_context_store,
+                criticality_assessor=mock_criticality_assessor,
+                telegram=mock_telegram,
+                market=mock_market,
+                stock_code="005930",
+                scan_candidates={},
+            )
+
+        # validate_order (which includes fat finger) must NOT be called for SELL
+        mock_risk.validate_order.assert_not_called()
+        # check_circuit_breaker MUST be called for SELL
+        mock_risk.check_circuit_breaker.assert_called_once()
+
+    @pytest.mark.asyncio
+    async def test_sell_circuit_breaker_still_applies(
+        self,
+        mock_broker: MagicMock,
+        mock_overseas_broker: MagicMock,
+        mock_scenario_engine: MagicMock,
+        mock_playbook: DayPlaybook,
+        mock_risk: MagicMock,
+        mock_db: MagicMock,
+        mock_decision_logger: MagicMock,
+        mock_context_store: MagicMock,
+        mock_criticality_assessor: MagicMock,
+        mock_telegram: MagicMock,
+        mock_market: MagicMock,
+    ) -> None:
+        """SELL orders must still respect the circuit breaker."""
+        mock_scenario_engine.evaluate = MagicMock(return_value=_make_sell_match())
+        mock_broker.get_balance = AsyncMock(
+            return_value={
+                "output1": [{"pdno": "005930", "ord_psbl_qty": "100"}],
+                "output2": [
+                    {
+                        "tot_evlu_amt": "10000000",
+                        "dnca_tot_amt": "5000000",
+                        "pchs_amt_smtl_amt": "5000000",
+                    }
+                ],
+            }
+        )
+        mock_risk.check_circuit_breaker.side_effect = CircuitBreakerTripped(
+            pnl_pct=-4.0, threshold=-3.0
+        )
+
+        with patch("src.main.log_trade"):
+            with pytest.raises(CircuitBreakerTripped):
+                await trading_cycle(
+                    broker=mock_broker,
+                    overseas_broker=mock_overseas_broker,
+                    scenario_engine=mock_scenario_engine,
+                    playbook=mock_playbook,
+                    risk=mock_risk,
+                    db_conn=mock_db,
+                    decision_logger=mock_decision_logger,
+                    context_store=mock_context_store,
+                    criticality_assessor=mock_criticality_assessor,
+                    telegram=mock_telegram,
+                    market=mock_market,
+                    stock_code="005930",
+                    scan_candidates={},
+                )
+
+        mock_risk.check_circuit_breaker.assert_called_once()
+        mock_risk.validate_order.assert_not_called()
+
 
 class TestRunFunctionTelegramIntegration:
     """Test telegram notifications in run function."""

tests/test_smart_scanner.py

@@ -350,6 +350,42 @@ class TestSmartVolatilityScanner:
         assert [c.stock_code for c in candidates] == ["ABCD"]
 
 
+class TestImpliedRSIFormula:
+    """Test the implied_rsi formula in SmartVolatilityScanner (issue #181)."""
+
+    def test_neutral_change_gives_neutral_rsi(self) -> None:
+        """0% change → implied_rsi = 50 (neutral)."""
+        # formula: 50 + (change_rate * 2.0)
+        rsi = max(0.0, min(100.0, 50.0 + (0.0 * 2.0)))
+        assert rsi == 50.0
+
+    def test_10pct_change_gives_rsi_70(self) -> None:
+        """10% upward change → implied_rsi = 70 (momentum signal)."""
+        rsi = max(0.0, min(100.0, 50.0 + (10.0 * 2.0)))
+        assert rsi == 70.0
+
+    def test_minus_10pct_gives_rsi_30(self) -> None:
+        """-10% change → implied_rsi = 30 (oversold signal)."""
+        rsi = max(0.0, min(100.0, 50.0 + (-10.0 * 2.0)))
+        assert rsi == 30.0
+
+    def test_saturation_at_25pct(self) -> None:
+        """Saturation occurs at >=25% change (not 12.5% as with old coefficient 4.0)."""
+        rsi_12pct = max(0.0, min(100.0, 50.0 + (12.5 * 2.0)))
+        rsi_25pct = max(0.0, min(100.0, 50.0 + (25.0 * 2.0)))
+        rsi_30pct = max(0.0, min(100.0, 50.0 + (30.0 * 2.0)))
+        # At 12.5% change: RSI = 75 (not 100, unlike old formula)
+        assert rsi_12pct == 75.0
+        # At 25%+ saturation
+        assert rsi_25pct == 100.0
+        assert rsi_30pct == 100.0  # Capped
+
+    def test_negative_saturation(self) -> None:
+        """Saturation at -25% gives RSI = 0."""
+        rsi = max(0.0, min(100.0, 50.0 + (-25.0 * 2.0)))
+        assert rsi == 0.0
+
+
 class TestRSICalculation:
     """Test RSI calculation in VolatilityAnalyzer."""