diff --git a/actions/sprints.ts b/actions/sprints.ts
index bf7dac3..4b6acbf 100644
--- a/actions/sprints.ts
+++ b/actions/sprints.ts
@@ -12,6 +12,7 @@ import {
   updateSprintGoalSchema,
 } from '@/lib/schemas/sprint'
 import { enforceUserRateLimit } from '@/lib/rate-limit'
+import { updateTaskStatusWithStoryPromotion } from '@/lib/tasks-status-update'
 
 async function getSession() {
   return getIronSession<SessionData>(await cookies(), sessionOptions)
@@ -272,3 +273,31 @@ export async function completeSprintAction(
   revalidatePath(`/products/${sprint.product_id}/sprint`)
   return { success: true }
 }
+
+export async function setAllSprintTasksDoneAction(
+  sprintId: string,
+): Promise<{ ok: true } | { ok: false; error: string }> {
+  const session = await getSession()
+  if (!session.userId) return { ok: false, error: 'Niet ingelogd' }
+  if (session.isDemo) return { ok: false, error: 'Niet beschikbaar in demo-modus' }
+
+  const sprint = await prisma.sprint.findFirst({
+    where: { id: sprintId, product: productAccessFilter(session.userId) },
+    select: { id: true, product_id: true },
+  })
+  if (!sprint) return { ok: false, error: 'Sprint niet gevonden' }
+
+  const tasks = await prisma.task.findMany({
+    where: { sprint_id: sprintId, product_id: sprint.product_id },
+    select: { id: true },
+  })
+
+  await prisma.$transaction(async (tx) => {
+    for (const task of tasks) {
+      await updateTaskStatusWithStoryPromotion(task.id, 'DONE', tx)
+    }
+  })
+
+  revalidatePath(`/products/${sprint.product_id}/sprint`)
+  return { ok: true }
+}