diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000..54db0d5
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,4 @@
+
+## 2024-07-27 - Optimize Job Event Sequence Calculation
+**Learning:** Loading lists of entities into memory (e.g., using `list_for_job(limit=1000)[-1]`) just to determine the maximum sequence number is an anti-pattern that behaves like an N+1 query memory leak.
+**Action:** Always use direct SQL aggregations (e.g., `select(func.coalesce(func.max(Model.field), 0))`) in repository methods to fetch scalar maximums in O(1) time rather than loading unneeded objects into memory.
diff --git a/apps/api/src/cortex_api/services/jobs.py b/apps/api/src/cortex_api/services/jobs.py
index f99216e..73b6ddc 100644
--- a/apps/api/src/cortex_api/services/jobs.py
+++ b/apps/api/src/cortex_api/services/jobs.py
@@ -110,8 +110,8 @@ async def cancel_job(uow: CortexUnitOfWork, job_id: str) -> JobStatusDetail:
     if updated is None:  # pragma: no cover - defensive
         raise NotFoundError(f"Job `{job_id}` was not found.")
 
-    existing_events = await uow.job_events.list_for_job(job_id, limit=1000)
-    next_sequence = existing_events[-1].sequence_no + 1 if existing_events else 1
+    max_seq = await uow.job_events.get_max_sequence_no(job_id)
+    next_sequence = max_seq + 1
     await uow.job_events.add(
         JobEventRecord(
             job_id=job_id,
diff --git a/packages/db/src/cortex_db/repositories.py b/packages/db/src/cortex_db/repositories.py
index 1b1d253..bdb042b 100644
--- a/packages/db/src/cortex_db/repositories.py
+++ b/packages/db/src/cortex_db/repositories.py
@@ -49,7 +49,7 @@
     SynthesisType,
     TenantRecord,
 )
-from sqlalchemy import desc, or_, select, update
+from sqlalchemy import desc, func, or_, select, update
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from .models import (
@@ -1651,6 +1651,14 @@ async def list_for_job(
         )
         return [_job_event_from_model(model) for model in result.scalars().all()]
 
+    async def get_max_sequence_no(self, job_id: str) -> int:
+        result = await self._session.execute(
+            select(func.coalesce(func.max(JobEventModel.sequence_no), 0)).where(
+                JobEventModel.job_id == job_id
+            )
+        )
+        return result.scalar_one()
+
 
 class ParseRunRepository:
     def __init__(self, session: AsyncSession) -> None:
diff --git a/packages/evaluation/src/cortex_evaluation/jobs.py b/packages/evaluation/src/cortex_evaluation/jobs.py
index 6b861f5..0d2a692 100644
--- a/packages/evaluation/src/cortex_evaluation/jobs.py
+++ b/packages/evaluation/src/cortex_evaluation/jobs.py
@@ -561,8 +561,8 @@ async def _append_event(
         message: str,
         details: dict[str, Any] | None = None,
     ) -> None:
-        existing_events = await uow.job_events.list_for_job(job.job_id, limit=1000)
-        next_sequence = existing_events[-1].sequence_no + 1 if existing_events else 1
+        max_seq = await uow.job_events.get_max_sequence_no(job.job_id)
+        next_sequence = max_seq + 1
         await uow.job_events.add(
             JobEventRecord(
                 job_id=job.job_id,
diff --git a/packages/knowledge/src/cortex_knowledge/jobs.py b/packages/knowledge/src/cortex_knowledge/jobs.py
index 63ef80a..1b66cb3 100644
--- a/packages/knowledge/src/cortex_knowledge/jobs.py
+++ b/packages/knowledge/src/cortex_knowledge/jobs.py
@@ -480,8 +480,8 @@ async def _append_event(
         message: str,
         details: dict[str, Any] | None = None,
     ) -> None:
-        existing_events = await uow.job_events.list_for_job(job.job_id, limit=1000)
-        next_sequence = existing_events[-1].sequence_no + 1 if existing_events else 1
+        max_seq = await uow.job_events.get_max_sequence_no(job.job_id)
+        next_sequence = max_seq + 1
         await uow.job_events.add(
             JobEventRecord(
                 job_id=job.job_id,
diff --git a/packages/parse/src/cortex_parse/jobs.py b/packages/parse/src/cortex_parse/jobs.py
index 63820aa..9f284a9 100644
--- a/packages/parse/src/cortex_parse/jobs.py
+++ b/packages/parse/src/cortex_parse/jobs.py
@@ -33,9 +33,7 @@ async def submit(
         idempotency_key: str | None = None,
         request_id: str | None = None,
     ) -> JobAccepted:
-        normalized_key = (
-            normalize_idempotency_key(idempotency_key) if idempotency_key else None
-        )
+        normalized_key = normalize_idempotency_key(idempotency_key) if idempotency_key else None
         if normalized_key is not None:
             existing = await uow.jobs.get_by_idempotency(
                 caller.tenant_id,
@@ -412,8 +410,8 @@ async def _append_event(
         message: str,
         details: dict[str, Any] | None = None,
     ) -> None:
-        existing_events = await uow.job_events.list_for_job(job.job_id, limit=1000)
-        next_sequence = existing_events[-1].sequence_no + 1 if existing_events else 1
+        max_seq = await uow.job_events.get_max_sequence_no(job.job_id)
+        next_sequence = max_seq + 1
         await uow.job_events.add(
             JobEventRecord(
                 job_id=job.job_id,
diff --git a/packages/synthesis/src/cortex_synthesis/jobs.py b/packages/synthesis/src/cortex_synthesis/jobs.py
index 547cd85..57d410c 100644
--- a/packages/synthesis/src/cortex_synthesis/jobs.py
+++ b/packages/synthesis/src/cortex_synthesis/jobs.py
@@ -401,8 +401,8 @@ async def _append_event(
         message: str,
         details: dict[str, Any] | None = None,
     ) -> None:
-        existing_events = await uow.job_events.list_for_job(job.job_id, limit=1000)
-        next_sequence = existing_events[-1].sequence_no + 1 if existing_events else 1
+        max_seq = await uow.job_events.get_max_sequence_no(job.job_id)
+        next_sequence = max_seq + 1
         await uow.job_events.add(
             JobEventRecord(
                 job_id=job.job_id,