diff --git a/app/services/documentary/frame_analysis_models.py b/app/services/documentary/frame_analysis_models.py
index 5dc0074..6ac419c 100644
--- a/app/services/documentary/frame_analysis_models.py
+++ b/app/services/documentary/frame_analysis_models.py
@@ -27,7 +27,7 @@ class FrameBatchResult:
     time_range: str
     raw_response: str
     frame_paths: list[str] = field(default_factory=list)
-    observations: list[dict] = field(default_factory=list)
-    summary: str = ""
+    frame_observations: list[dict] = field(default_factory=list)
+    overall_activity_summary: str = ""
     fallback_summary: str = ""
     error_message: str = ""
diff --git a/tests/test_documentary_frame_analysis_service.py b/tests/test_documentary_frame_analysis_service.py
index bfdde3e..d5c4c11 100644
--- a/tests/test_documentary_frame_analysis_service.py
+++ b/tests/test_documentary_frame_analysis_service.py
@@ -46,6 +46,22 @@ class DocumentaryFrameAnalysisServiceTests(unittest.TestCase):
         self.assertEqual("", batch.raw_response)
         self.assertTrue(batch.fallback_summary)
 
+    def test_failed_batch_result_uses_prompt_contract_field_names(self):
+        service = DocumentaryFrameAnalysisService()
+
+        batch = service._build_failed_batch_result(
+            batch_index=4,
+            raw_response="not-json",
+            error_message="JSON decode failed",
+            frame_paths=["/tmp/keyframe_000002_000002000.jpg"],
+            time_range="00:00:06,000-00:00:09,000",
+        )
+
+        self.assertEqual([], batch.frame_observations)
+        self.assertEqual("", batch.overall_activity_summary)
+        self.assertFalse(hasattr(batch, "observations"))
+        self.assertFalse(hasattr(batch, "summary"))
+
 
 class DocumentaryAnalysisConfigTests(unittest.TestCase):
     def test_config_rejects_non_positive_frame_interval(self):