diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000..2f23a5f
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## 2024-06-25 - Single loop for Prisma relations
+**Learning:** When processing large datasets from Prisma `include` blocks, avoid multiple iteration passes (like chained `.reduce()` or `.map()` calls) over the in-memory relations.
+**Action:** Prefer a single loop to minimize iteration overhead and reduce potential memory bottlenecks.
diff --git a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/[sessionId]/route.ts b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/[sessionId]/route.ts
index 35486b8..9322fd0 100644
--- a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/[sessionId]/route.ts
+++ b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/[sessionId]/route.ts
@@ -43,9 +43,17 @@ export async function GET(
       return forbiddenByRole(access.role, '본인 세션만 열람 가능')
     }
 
-    const totalInput = session.usageRecords.reduce((sum, r) => sum + r.inputTokens, 0)
-    const totalOutput = session.usageRecords.reduce((sum, r) => sum + r.outputTokens, 0)
-    const totalCost = session.usageRecords.reduce((sum, r) => sum + (r.estimatedCostUsd ?? 0), 0)
+    let totalInput = 0
+    let totalOutput = 0
+    let totalCost = 0
+
+    // ⚡ Bolt: Using a single loop to calculate totals instead of multiple .reduce() passes
+    // This reduces memory bottlenecks when processing large datasets from Prisma `include` blocks.
+    for (const r of session.usageRecords) {
+      totalInput += r.inputTokens
+      totalOutput += r.outputTokens
+      totalCost += r.estimatedCostUsd ?? 0
+    }
 
     const usageTimeline: SessionTimelineUsage[] = session.usageRecords.map((r) => ({
       timestamp: r.timestamp.toISOString(),
diff --git a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
index 25fbe70..fff9a22 100644
--- a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
+++ b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
@@ -33,14 +33,19 @@ const sessionInclude = {
 type SessionWithInclude = Prisma.ClaudeSessionGetPayload<{ include: typeof sessionInclude }>
 
 function getSessionTotals(session: SessionWithInclude) {
-  return {
-    inputTokens: session.usageRecords.reduce((sum, r) => sum + r.inputTokens, 0),
-    outputTokens: session.usageRecords.reduce((sum, r) => sum + r.outputTokens, 0),
-    estimatedCostUsd: session.usageRecords.reduce(
-      (sum, r) => sum + (r.estimatedCostUsd ?? 0),
-      0,
-    ),
+  let inputTokens = 0
+  let outputTokens = 0
+  let estimatedCostUsd = 0
+
+  // ⚡ Bolt: Using a single loop to calculate totals instead of multiple .reduce() passes
+  // This reduces memory bottlenecks when processing large datasets from Prisma `include` blocks.
+  for (const r of session.usageRecords) {
+    inputTokens += r.inputTokens
+    outputTokens += r.outputTokens
+    estimatedCostUsd += r.estimatedCostUsd ?? 0
   }
+
+  return { inputTokens, outputTokens, estimatedCostUsd }
 }
 
 function mapSessionItem(session: SessionWithInclude): SessionItem {