ref(ai-monitoring): Align list titles with detail selection

src/sentry/ai_monitoring/utils.py

@@ -84,6 +84,10 @@ def clamp_conversation_id_for_storage(conversation_id: str) -> str:
     return conversation_id[:CONVERSATION_ID_TRUNCATE_TO] + "..."
 
 
+# Earliest title source wins (closest to the first user message); project_id breaks ties.
+TITLE_ORDER_BY = (F("title_source_timestamp").asc(nulls_last=True), "project_id")
+
+
 def fetch_conversation_title(
     conversation_id: str,
     project_ids: Collection[int],
@@ -105,7 +109,7 @@ def fetch_conversation_title(
             title__isnull=False,
         )
         .exclude(title="")
-        .order_by(F("title_source_timestamp").asc(nulls_last=True), "project_id")
+        .order_by(*TITLE_ORDER_BY)
         .first()
     )
 
@@ -127,18 +131,22 @@ def fetch_conversation_titles(
         for conversation_id, _ in requested_pairs
     }
 
-    rows = AIConversationMetadata.objects.filter(
-        project_id__in={project_id for _, project_id in requested_pairs},
-        conversation_id_hash__in=conversation_id_by_hash,
-        title__isnull=False,
-    ).values_list("conversation_id_hash", "project_id", "title")
+    rows = (
+        AIConversationMetadata.objects.filter(
+            project_id__in={project_id for _, project_id in requested_pairs},
+            conversation_id_hash__in=conversation_id_by_hash,
+            title__isnull=False,
+        )
+        .exclude(title="")
+        .values_list("conversation_id_hash", "project_id", "title")
+    )
 
     # The filter matches the cross product of the hashes and the projects, so drop
     # any (conversation, project) combination the caller did not ask about.
     titles: dict[tuple[str, int], str] = {}
     for row_hash, project_id, title in rows:
         pair = (conversation_id_by_hash[row_hash], project_id)
-        if title and pair in requested_pairs:
+        if pair in requested_pairs:
             titles[pair] = title
 
     return titles

src/sentry/api/endpoints/organization_ai_conversations.py

@@ -592,17 +592,27 @@ def _apply_titles(
         conversations_map: dict[str, dict[str, Any]],
         project_ids_by_conversation: Mapping[str, set[int]],
     ) -> None:
-        """Attach stored conversation titles, leaving `title` as None when we have none."""
+        """Set each conversation's `title` from storage when present.
+
+        On lookup failure, log and leave titles unset so the list response still succeeds.
+        """
         sorted_project_ids = {
             conv_id: sorted(project_ids_by_conversation.get(conv_id, ()))
             for conv_id in conversations_map
         }
-        titles = fetch_conversation_titles(
-            [
-                (conv_id, project_id)
-                for conv_id, project_ids in sorted_project_ids.items()
-                for project_id in project_ids
-            ]
-        )
+        pairs = [
+            (conv_id, project_id)
+            for conv_id, project_ids in sorted_project_ids.items()
+            for project_id in project_ids
+        ]
+        try:
+            titles = fetch_conversation_titles(pairs)
+        except Exception:
+            logger.exception(
+                "Failed to resolve titles for AI conversations",
+                extra={"project_ids": sorted({project_id for _, project_id in pairs})},
+            )
+            return
+
         for conv_id, conversation in conversations_map.items():
             conversation["title"] = _first_title(titles, conv_id, sorted_project_ids[conv_id])

tests/sentry/api/endpoints/test_organization_ai_conversations.py

@@ -1,6 +1,7 @@
 import json  # noqa: S003
 from datetime import timedelta
 from typing import Any
+from unittest.mock import MagicMock, patch
 from uuid import uuid4
 
 from django.urls import reverse
@@ -1597,3 +1598,27 @@ def test_title_found_when_only_higher_project_id_has_one(self) -> None:
         assert response.status_code == 200, response.data
         assert len(response.data) == 1
         assert response.data[0]["title"] == "Higher project id title"
+
+    @patch(
+        "sentry.api.endpoints.organization_ai_conversations.fetch_conversation_titles",
+        side_effect=Exception("metadata unavailable"),
+    )
+    def test_title_lookup_failure_does_not_break_list(
+        self, mock_fetch_conversation_titles: MagicMock
+    ) -> None:
+        now = before_now(days=25).replace(microsecond=0)
+        conversation_id = uuid4().hex
+
+        self._store_conversation_span(conversation_id, now)
+
+        query = {
+            "project": [self.project.id],
+            "start": (now - timedelta(hours=1)).isoformat(),
+            "end": (now + timedelta(hours=1)).isoformat(),
+        }
+
+        response = self.do_request(query)
+        assert response.status_code == 200, response.data
+        assert len(response.data) == 1
+        assert response.data[0]["title"] is None
+        assert mock_fetch_conversation_titles.call_count == 1