diff --git a/backend/apis/GoogleSolarApi.py b/backend/apis/GoogleSolarApi.py
index 589d3a04..7c90307c 100644
--- a/backend/apis/GoogleSolarApi.py
+++ b/backend/apis/GoogleSolarApi.py
@@ -1,8 +1,6 @@
-import time
-import requests
 import pandas as pd
 import numpy as np
-from typing import List
+from typing import Any, List
 from functools import lru_cache
 from sklearn.preprocessing import MinMaxScaler
 from tqdm import tqdm
@@ -84,7 +82,7 @@ class GoogleSolarApi:
 
         self.allowed_segment_indices = None
 
-    def get_building_insights(self, longitude: float, latitude: float, required_quality: str = "MEDIUM") -> dict:
+    def get_building_insights(self, longitude: float, latitude: float, required_quality: str = "MEDIUM") -> dict[str, Any]:
         try:
             return self._solar_client.get_building_insights(longitude, latitude, required_quality)  # type: ignore[arg-type]
         except BuildingInsightsNotFoundError:
diff --git a/tests/infrastructure/solar/test_google_solar_api_wiring.py b/tests/infrastructure/solar/test_google_solar_api_wiring.py
index 52618f9d..77988645 100644
--- a/tests/infrastructure/solar/test_google_solar_api_wiring.py
+++ b/tests/infrastructure/solar/test_google_solar_api_wiring.py
@@ -1,5 +1,5 @@
 from typing import Any
-from unittest.mock import MagicMock, patch
+from unittest.mock import patch
 
 from backend.apis.GoogleSolarApi import GoogleSolarApi
 from infrastructure.solar.google_solar_api_client import (
@@ -24,3 +24,24 @@ def test_get_building_insights_delegates_to_solar_client() -> None:
 
     # Assert
     assert result == payload
+
+
+# ---------------------------------------------------------------------------
+# Slice 2: BuildingInsightsNotFoundError translates to sentinel dict
+# ---------------------------------------------------------------------------
+
+
+def test_get_building_insights_returns_sentinel_on_not_found() -> None:
+    # Arrange
+    with patch.object(
+        GoogleSolarApiClient,
+        "get_building_insights",
+        side_effect=BuildingInsightsNotFoundError,
+    ):
+        api = GoogleSolarApi(api_key="test-key", solar_materials=[])
+
+        # Act
+        result = api.get_building_insights(longitude=-0.1278, latitude=51.5074)
+
+    # Assert
+    assert result == {"error": GoogleSolarApiClient.ENTITY_NOT_FOUND_ERROR}