Fix: List index bug in outlier detection, add error logging

Bug #1: Fixed IndexError in outlier_detection.py:256
- Missing enumerate() caused stale loop var to access beyond bounds
- Occurred when hard bounds filtered deals before IQR processing
- Added test reproducing exact scenario (21 deals → 8 filtered)

Bug #2: Added stack traces to all MCP tool error logs
- Added exc_info=True to 10 MCP tools' error handlers
- Improves debugging by logging full stack traces

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

nadlan_mcp/fastmcp_server.py

@@ -122,7 +122,7 @@ def autocomplete_address(search_text: str) -> str:
         return json.dumps(formatted_results, ensure_ascii=False, indent=2)
 
     except Exception as e:
-        logger.error(f"Error in autocomplete_address: {e}")
+        logger.error(f"Error in autocomplete_address: {e}", exc_info=True)
         return f"Error searching for address: {str(e)}"
 
 
@@ -164,7 +164,7 @@ def get_deals_by_radius(latitude: float, longitude: float, radius_meters: int =
         )
 
     except Exception as e:
-        logger.error(f"Error in get_deals_by_radius: {e}")
+        logger.error(f"Error in get_deals_by_radius: {e}", exc_info=True)
         return f"Error fetching polygons by radius: {str(e)}"
 
 
@@ -221,7 +221,7 @@ def get_street_deals(polygon_id: str, limit: int = 100, deal_type: int = 2) -> s
         )
 
     except Exception as e:
-        logger.error(f"Error in get_street_deals: {e}")
+        logger.error(f"Error in get_street_deals: {e}", exc_info=True)
         return f"Error fetching street deals: {str(e)}"
 
 
@@ -343,7 +343,7 @@ def find_recent_deals_for_address(
         )
 
     except Exception as e:
-        logger.error(f"Error in find_recent_deals_for_address: {e}")
+        logger.error(f"Error in find_recent_deals_for_address: {e}", exc_info=True)
         return f"Error analyzing address: {str(e)}"
 
 
@@ -400,7 +400,7 @@ def get_neighborhood_deals(polygon_id: str, limit: int = 100, deal_type: int = 2
         )
 
     except Exception as e:
-        logger.error(f"Error in get_neighborhood_deals: {e}")
+        logger.error(f"Error in get_neighborhood_deals: {e}", exc_info=True)
         return f"Error fetching neighborhood deals: {str(e)}"
 
 
@@ -620,7 +620,7 @@ def analyze_market_trends(
         )
 
     except Exception as e:
-        logger.error(f"Error in analyze_market_trends: {e}")
+        logger.error(f"Error in analyze_market_trends: {e}", exc_info=True)
         return f"Error analyzing market trends: {str(e)}"
 
 
@@ -753,7 +753,7 @@ def compare_addresses(addresses: List[str]) -> str:
         )
 
     except Exception as e:
-        logger.error(f"Error in compare_addresses: {e}")
+        logger.error(f"Error in compare_addresses: {e}", exc_info=True)
         return f"Error comparing addresses: {str(e)}"
 
 
@@ -941,7 +941,7 @@ def get_valuation_comparables(
         )
 
     except Exception as e:
-        logger.error(f"Error in get_valuation_comparables: {e}")
+        logger.error(f"Error in get_valuation_comparables: {e}", exc_info=True)
         return f"Error getting valuation comparables: {str(e)}"
 
 
@@ -1037,7 +1037,7 @@ def get_deal_statistics(
         )
 
     except Exception as e:
-        logger.error(f"Error in get_deal_statistics: {e}")
+        logger.error(f"Error in get_deal_statistics: {e}", exc_info=True)
         return f"Error calculating deal statistics: {str(e)}"
 
 
@@ -1154,7 +1154,7 @@ def get_market_activity_metrics(address: str, years_back: int = 2, radius_meters
         )
 
     except Exception as e:
-        logger.error(f"Error in get_market_activity_metrics: {e}")
+        logger.error(f"Error in get_market_activity_metrics: {e}", exc_info=True)
         return f"Error analyzing market activity: {str(e)}"
 
 

nadlan_mcp/govmap/outlier_detection.py

@@ -253,7 +253,7 @@ def filter_deals_for_analysis(
         if metric == "price_per_sqm":
             values = [
                 deal.price_per_sqm
-                for deal in deals
+                for i, deal in enumerate(deals)
                 if deal.price_per_sqm is not None and not filters_to_remove[i]
             ]
             value_indices = [

tests/govmap/test_outlier_detection.py

@@ -329,3 +329,44 @@ class TestIntegration:
         # The data error should be filtered by hard bounds (price_per_sqm > 100K)
         assert len(filtered) == 12
         assert report["outliers_removed"] == 1
+
+    def test_edge_case_few_deals_with_hard_bounds_filter(self):
+        """
+        Test edge case: Small dataset where hard bounds filter removes some deals.
+
+        This reproduces the bug where list index goes out of range when:
+        - Initial dataset is small (e.g., 21 deals)
+        - Hard bounds filter removes some deals (e.g., 8 outliers)
+        - Remaining dataset is processed with IQR
+
+        The bug was in line 257 where enumerate() was missing, causing
+        the value_indices to be misaligned with the statistical_outliers list.
+        """
+        # Create 21 deals with some extreme outliers
+        deals = []
+
+        # 13 normal deals (around 10K per sqm)
+        for i in range(13):
+            deals.append(
+                Deal(objectid=i, deal_amount=1000000, deal_date=date(2023, 1, 1), asset_area=100)
+            )
+
+        # 8 extreme outliers that will be caught by hard bounds (price_per_sqm > 100K)
+        for i in range(13, 21):
+            deals.append(
+                Deal(objectid=i, deal_amount=200000000, deal_date=date(2023, 1, 1), asset_area=100)
+            )
+
+        config = GovmapConfig(
+            analysis_outlier_method="iqr",
+            analysis_iqr_multiplier=1.0,
+            analysis_price_per_sqm_max=100000,
+        )
+
+        # This should not raise IndexError
+        filtered, report = filter_deals_for_analysis(deals, config, metric="price_per_sqm")
+
+        # Hard bounds should filter the 8 extreme outliers
+        assert len(filtered) == 13
+        assert report["outliers_removed"] == 8
+        assert report["method_used"] == "iqr"