diff --git a/src/modules/ai-runtime/job-reaper.service.spec.ts b/src/modules/ai-runtime/job-reaper.service.spec.ts
index 9deb65a..8c547c3 100644
--- a/src/modules/ai-runtime/job-reaper.service.spec.ts
+++ b/src/modules/ai-runtime/job-reaper.service.spec.ts
@@ -6,8 +6,8 @@ describe('JobReaperService', () => {
   let mockFindMany: jest.Mock;
 
   beforeEach(() => {
-    mockUpdateMany = jest.fn();
-    mockFindMany = jest.fn();
+    mockUpdateMany = jest.fn().mockResolvedValue({ count: 0 });
+    mockFindMany = jest.fn().mockResolvedValue([]); // default: empty batch → breaks loop
     const mockPrisma = {
       aiRuntimeJob: { updateMany: mockUpdateMany, findMany: mockFindMany },
     } as any;
@@ -20,8 +20,7 @@ describe('JobReaperService', () => {
   });
 
   it('expires locked jobs past lockUntil', async () => {
-    mockUpdateMany.mockResolvedValue({ count: 2 });
-    mockFindMany.mockResolvedValue([]);
+    mockUpdateMany.mockResolvedValueOnce({ count: 2 }); // locked step
 
     const result = await service.reap();
 
@@ -34,12 +33,13 @@ describe('JobReaperService', () => {
 
   it('expires running jobs past timeout', async () => {
     const now = Date.now();
-    mockUpdateMany.mockResolvedValueOnce({ count: 0 }); // locked
+    // Running batch 1: has a stuck job
     mockFindMany.mockResolvedValueOnce([
-      { id: 'j1', startedAt: new Date(now - 180_000), timeoutSeconds: 120, retryCount: 0, maxRetryCount: 3 },
+      { id: 'j1', startedAt: new Date(now - 180_000), timeoutSeconds: 120 },
     ]);
-    mockUpdateMany.mockResolvedValueOnce({ count: 1 }); // running expired
-    mockFindMany.mockResolvedValueOnce([]); // expired jobs
+    // Running batch 2: empty → loop breaks (default mock handles this)
+    mockUpdateMany.mockResolvedValueOnce({ count: 0 }); // locked step
+    mockUpdateMany.mockResolvedValueOnce({ count: 1 }); // expire running
 
     const result = await service.reap();
 
@@ -51,14 +51,18 @@ describe('JobReaperService', () => {
   });
 
   it('retries expired jobs with remaining retries', async () => {
-    mockUpdateMany.mockResolvedValueOnce({ count: 0 }); // locked
-    mockFindMany.mockResolvedValueOnce([]); // running
-    mockFindMany.mockResolvedValueOnce([
-      { id: 'j1', retryCount: 0, maxRetryCount: 3 },
-      { id: 'j2', retryCount: 3, maxRetryCount: 3 },
-    ]);
-    mockUpdateMany.mockResolvedValueOnce({ count: 1 }); // retry j1
-    mockUpdateMany.mockResolvedValueOnce({ count: 1 }); // fail j2
+    // Running loop: empty on first call → breaks
+    // Expired batch 1: has 2 expired jobs
+    mockFindMany
+      .mockResolvedValueOnce([]) // running batch 1 (empty → skip)
+      .mockResolvedValueOnce([
+        { id: 'j1', retryCount: 0, maxRetryCount: 3 },
+        { id: 'j2', retryCount: 3, maxRetryCount: 3 },
+      ]);
+    mockUpdateMany
+      .mockResolvedValueOnce({ count: 0 }) // locked
+      .mockResolvedValueOnce({ count: 1 }) // retry j1
+      .mockResolvedValueOnce({ count: 1 }); // fail j2
 
     const result = await service.reap();
 
@@ -67,11 +71,23 @@ describe('JobReaperService', () => {
   });
 
   it('handles no stuck jobs gracefully', async () => {
-    mockUpdateMany.mockResolvedValue({ count: 0 });
-    mockFindMany.mockResolvedValue([]);
-
     const result = await service.reap();
-
     expect(result).toEqual({ expired: 0, retried: 0, failed: 0 });
   });
+
+  it('processes running jobs correctly with single batch', async () => {
+    mockFindMany.mockReset().mockResolvedValue([]);
+    mockUpdateMany.mockReset().mockResolvedValue({ count: 0 });
+    const now = Date.now();
+    // Batch returns fewer than BATCH_SIZE → loop stops naturally
+    mockFindMany.mockResolvedValueOnce([
+      { id: 'j1', startedAt: new Date(now - 180_000), timeoutSeconds: 120 },
+      { id: 'j2', startedAt: new Date(now - 180_000), timeoutSeconds: 120 },
+    ]);
+    mockUpdateMany.mockResolvedValueOnce({ count: 0 }); // locked step
+    mockUpdateMany.mockResolvedValueOnce({ count: 2 }); // expire running
+
+    const result = await service.reap();
+    expect(result.expired).toBe(2);
+  });
 });
diff --git a/src/modules/ai-runtime/job-reaper.service.ts b/src/modules/ai-runtime/job-reaper.service.ts
index 7418863..861643a 100644
--- a/src/modules/ai-runtime/job-reaper.service.ts
+++ b/src/modules/ai-runtime/job-reaper.service.ts
@@ -2,6 +2,7 @@ import { Injectable, Logger, OnModuleInit, OnModuleDestroy } from '@nestjs/commo
 import { PrismaService } from '../../infrastructure/database/prisma.service';
 
 const REAP_INTERVAL_MS = 30_000; // every 30 seconds
+const REAP_BATCH_SIZE = 500;
 
 @Injectable()
 export class JobReaperService implements OnModuleInit, OnModuleDestroy {
@@ -30,59 +31,76 @@ export class JobReaperService implements OnModuleInit, OnModuleDestroy {
     });
 
     // 2. Expire stuck running jobs (startedAt + timeoutSeconds < now)
-    // We can't do arithmetic in Prisma where, so fetch IDs and update
-    const stuckRunning = await this.prisma.aiRuntimeJob.findMany({
-      where: { status: 'running' },
-      select: { id: true, startedAt: true, timeoutSeconds: true, retryCount: true, maxRetryCount: true },
-      take: 500,
-    });
-    const stuckIds = stuckRunning
-      .filter(j => j.startedAt && (now.getTime() - j.startedAt.getTime()) > j.timeoutSeconds * 1000)
-      .map(j => j.id);
-
+    // We can't do arithmetic in Prisma where, so fetch IDs in batches and filter in memory
     let expiredRunning = 0;
-    if (stuckIds.length > 0) {
-      const result = await this.prisma.aiRuntimeJob.updateMany({
-        where: { id: { in: stuckIds }, status: 'running' },
-        data: { status: 'expired' },
+    let cursor: string | undefined;
+    let hasMore = true;
+    while (hasMore) {
+      const batch = await this.prisma.aiRuntimeJob.findMany({
+        where: { status: 'running' },
+        select: { id: true, startedAt: true, timeoutSeconds: true },
+        take: REAP_BATCH_SIZE,
+        ...(cursor ? { cursor: { id: cursor }, skip: 1 } : {}),
+        orderBy: { id: 'asc' },
       });
-      expiredRunning = result.count;
+      if (batch.length === 0) { hasMore = false; break; }
+
+      const stuckIds = batch
+        .filter(j => j.startedAt && (now.getTime() - j.startedAt.getTime()) > j.timeoutSeconds * 1000)
+        .map(j => j.id);
+
+      if (stuckIds.length > 0) {
+        const result = await this.prisma.aiRuntimeJob.updateMany({
+          where: { id: { in: stuckIds }, status: 'running' },
+          data: { status: 'expired' },
+        });
+        expiredRunning += result.count;
+      }
+      cursor = batch[batch.length - 1].id;
+      if (batch.length < REAP_BATCH_SIZE) hasMore = false;
     }
 
     // 3. Retry expired jobs where retryCount < maxRetryCount
-    // Prisma doesn't support comparing two columns in where, so fetch and batch
-    const expiredJobs = await this.prisma.aiRuntimeJob.findMany({
-      where: { status: 'expired' },
-      select: { id: true, retryCount: true, maxRetryCount: true },
-      take: 500,
-    });
-
-    const retryIds = expiredJobs.filter(j => j.retryCount < j.maxRetryCount).map(j => j.id);
-    const failIds = expiredJobs.filter(j => j.retryCount >= j.maxRetryCount).map(j => j.id);
-
     let retried = 0;
     let failed = 0;
-
-    if (retryIds.length > 0) {
-      const result = await this.prisma.aiRuntimeJob.updateMany({
-        where: { id: { in: retryIds }, status: 'expired' },
-        data: {
-          status: 'pending',
-          lockedBy: null,
-          lockedAt: null,
-          lockUntil: null,
-          retryCount: { increment: 1 },
-        },
+    cursor = undefined;
+    hasMore = true;
+    while (hasMore) {
+      const batch = await this.prisma.aiRuntimeJob.findMany({
+        where: { status: 'expired' },
+        select: { id: true, retryCount: true, maxRetryCount: true },
+        take: REAP_BATCH_SIZE,
+        ...(cursor ? { cursor: { id: cursor }, skip: 1 } : {}),
+        orderBy: { id: 'asc' },
       });
-      retried = result.count;
-    }
+      if (batch.length === 0) { hasMore = false; break; }
 
-    if (failIds.length > 0) {
-      const result = await this.prisma.aiRuntimeJob.updateMany({
-        where: { id: { in: failIds }, status: 'expired' },
-        data: { status: 'failed', finishedAt: new Date() },
-      });
-      failed = result.count;
+      const retryIds = batch.filter(j => j.retryCount < j.maxRetryCount).map(j => j.id);
+      const failIds = batch.filter(j => j.retryCount >= j.maxRetryCount).map(j => j.id);
+
+      if (retryIds.length > 0) {
+        const result = await this.prisma.aiRuntimeJob.updateMany({
+          where: { id: { in: retryIds }, status: 'expired' },
+          data: {
+            status: 'pending',
+            lockedBy: null,
+            lockedAt: null,
+            lockUntil: null,
+            retryCount: { increment: 1 },
+          },
+        });
+        retried += result.count;
+      }
+
+      if (failIds.length > 0) {
+        const result = await this.prisma.aiRuntimeJob.updateMany({
+          where: { id: { in: failIds }, status: 'expired' },
+          data: { status: 'failed', finishedAt: new Date() },
+        });
+        failed += result.count;
+      }
+      cursor = batch[batch.length - 1].id;
+      if (batch.length < REAP_BATCH_SIZE) hasMore = false;
     }
 
     const total = expiredLocks.count + expiredRunning + retried + failed;