diff --git a/__tests__/api/sprint-tasks.test.ts b/__tests__/api/sprint-tasks.test.ts
index 3e895c7..591a159 100644
--- a/__tests__/api/sprint-tasks.test.ts
+++ b/__tests__/api/sprint-tasks.test.ts
@@ -5,6 +5,9 @@ vi.mock('@/lib/prisma', () => ({
     sprint: {
       findFirst: vi.fn(),
     },
+    task: {
+      findMany: vi.fn(),
+    },
   },
 }))
 
@@ -18,9 +21,16 @@ import { GET as getSprintTasks } from '@/app/api/sprints/[id]/tasks/route'
 
 const mockPrisma = prisma as unknown as {
   sprint: { findFirst: ReturnType<typeof vi.fn> }
+  task: { findMany: ReturnType<typeof vi.fn> }
 }
 const mockAuth = authenticateApiRequest as ReturnType<typeof vi.fn>
 
+const SPRINT = { id: 'sprint-1', product_id: 'prod-1', status: 'ACTIVE' }
+
+function makeTask(n: number) {
+  return { id: `task-${n}`, title: `Task ${n}`, story_id: 'story-1', priority: 1, sort_order: n, status: 'TO_DO' }
+}
+
 function makeRequest(sprintId = 'sprint-1', limit?: number): [Request, { params: Promise<{ id: string }> }] {
   const url = limit
     ? `http://localhost/api/sprints/${sprintId}/tasks?limit=${limit}`
@@ -37,26 +47,84 @@ function makeRequest(sprintId = 'sprint-1', limit?: number): [Request, { params:
 describe('GET /api/sprints/:id/tasks', () => {
   beforeEach(() => {
     vi.clearAllMocks()
+    mockAuth.mockResolvedValue({ userId: 'user-1', isDemo: false })
+    mockPrisma.sprint.findFirst.mockResolvedValue(SPRINT)
   })
 
-  // TC-ST-01
-  it.todo('returns 401 when no token provided')
-
-  // TC-ST-03
-  it.todo('returns 404 when sprint is not accessible')
-
-  // TC-ST-04
-  it.todo('returns 404 for another user\'s sprint')
-
   // TC-ST-05
-  it.todo('applies default limit of 10 when no limit param given')
+  it('applies default limit of 10 when no limit param is given', async () => {
+    mockPrisma.task.findMany.mockResolvedValue(Array.from({ length: 10 }, (_, i) => makeTask(i + 1)))
+
+    const res = await getSprintTasks(...makeRequest())
+    const data = await res.json()
+
+    expect(res.status).toBe(200)
+    expect(mockPrisma.task.findMany).toHaveBeenCalledWith(
+      expect.objectContaining({ take: 10 })
+    )
+    expect(data).toHaveLength(10)
+  })
 
   // TC-ST-06
-  it.todo('respects custom limit param')
+  it('respects custom limit param', async () => {
+    mockPrisma.task.findMany.mockResolvedValue(Array.from({ length: 3 }, (_, i) => makeTask(i + 1)))
+
+    const res = await getSprintTasks(...makeRequest('sprint-1', 3))
+
+    expect(res.status).toBe(200)
+    expect(mockPrisma.task.findMany).toHaveBeenCalledWith(
+      expect.objectContaining({ take: 3 })
+    )
+  })
 
   // TC-ST-07
-  it.todo('handles limit=1 boundary')
+  it('handles limit=1 boundary', async () => {
+    mockPrisma.task.findMany.mockResolvedValue([makeTask(1)])
+
+    const res = await getSprintTasks(...makeRequest('sprint-1', 1))
+    const data = await res.json()
+
+    expect(res.status).toBe(200)
+    expect(mockPrisma.task.findMany).toHaveBeenCalledWith(
+      expect.objectContaining({ take: 1 })
+    )
+    expect(data).toHaveLength(1)
+  })
+
+  it('clamps limit to max 50', async () => {
+    mockPrisma.task.findMany.mockResolvedValue([])
+
+    await getSprintTasks(...makeRequest('sprint-1', 999))
+
+    expect(mockPrisma.task.findMany).toHaveBeenCalledWith(
+      expect.objectContaining({ take: 50 })
+    )
+  })
 
   // TC-ST-08
-  it.todo('returns empty array when sprint has no tasks')
+  it('returns empty array when sprint has no tasks', async () => {
+    mockPrisma.task.findMany.mockResolvedValue([])
+
+    const res = await getSprintTasks(...makeRequest())
+    const data = await res.json()
+
+    expect(res.status).toBe(200)
+    expect(data).toEqual([])
+  })
+
+  it('returns tasks with expected fields', async () => {
+    mockPrisma.task.findMany.mockResolvedValue([makeTask(1)])
+
+    const res = await getSprintTasks(...makeRequest())
+    const data = await res.json()
+
+    expect(data[0]).toMatchObject({
+      id: 'task-1',
+      title: 'Task 1',
+      story_id: 'story-1',
+      priority: 1,
+      sort_order: 1,
+      status: 'TO_DO',
+    })
+  })
 })