Keep partial rewrite results from LLM batches

ai_daily_report/rewrite.py

@@ -73,9 +73,6 @@ def _apply_rewrite_batch(batch: list[NewsItem], llm_call: RewriteLlmCall) -> int
             by_id[item_id].title = title
             by_id[item_id].summary = summary
             seen_ids.add(item_id)
-    for item in batch:
-        if item.id not in seen_ids:
-            raise ValueError(f"missing_rewrite_for_item: {item.id}")
     return len(seen_ids)
 
 
@@ -89,11 +86,19 @@ def rewrite_items(
 ) -> tuple[list[NewsItem], dict[str, Any]]:
     rewritten_count = 0
     fallback_count = 0
+    missing_rewrite_count = 0
     errors: list[str] = []
 
     for batch in _chunks(items, max(1, batch_size)):
         try:
-            rewritten_count += _apply_rewrite_batch(batch, llm_call)
+            batch_rewritten_count = _apply_rewrite_batch(batch, llm_call)
+            rewritten_count += batch_rewritten_count
+            for item in batch:
+                if item.title is None or item.summary is None:
+                    errors.append(f"missing_rewrite_for_item: {item.id}")
+                    _fallback(item)
+                    fallback_count += 1
+                    missing_rewrite_count += 1
         except Exception as exc:
             errors.append(f"batch:{type(exc).__name__}: {exc}")
             if _is_transient_llm_error(exc):
@@ -123,6 +128,7 @@ def rewrite_items(
         "input_count": len(items),
         "rewritten_count": rewritten_count,
         "fallback_count": fallback_count,
+        "missing_rewrite_count": missing_rewrite_count,
         "fallback_ratio": round(fallback_ratio, 4),
         "batch_count": len(_chunks(items, max(1, batch_size))),
         "errors": errors,

tests/test_stage4_rewrite.py

@@ -107,6 +107,27 @@ class Stage4RewriteTests(unittest.TestCase):
         self.assertEqual([item.title for item in rewritten], ["OpenAI launches GPT-5 API", "OpenAI launches GPT-5 API"])
         self.assertEqual(report["fallback_count"], 2)
 
+    def test_rewrite_items_keeps_partial_batch_rewrites_when_some_ids_are_missing(self):
+        items = [news_item("a"), news_item("b"), news_item("c")]
+
+        def llm_call(prompt):
+            return json.dumps(
+                {
+                    "rewrites": [
+                        {"id": "a", "title": "title a", "summary": "summary a", "flags": []},
+                        {"id": "c", "title": "title c", "summary": "summary c", "flags": []},
+                    ]
+                }
+            )
+
+        rewritten, report = rewrite_items(items, llm_call=llm_call, batch_size=3, max_fallback_ratio=0.5)
+
+        self.assertEqual([item.title for item in rewritten], ["title a", "OpenAI launches GPT-5 API", "title c"])
+        self.assertEqual(report["rewritten_count"], 2)
+        self.assertEqual(report["fallback_count"], 1)
+        self.assertEqual(report["missing_rewrite_count"], 1)
+        self.assertEqual(report["blocking_errors"], [])
+
     def test_rewrite_items_defaults_to_large_batches_to_reduce_llm_requests(self):
         items = [news_item(str(index)) for index in range(61)]
         batch_sizes = []