diff --git a/actions/user-questions.ts b/actions/user-questions.ts
new file mode 100644
index 0000000..3a076fa
--- /dev/null
+++ b/actions/user-questions.ts
@@ -0,0 +1,102 @@
+'use server'
+
+import { revalidatePath } from 'next/cache'
+import { cookies } from 'next/headers'
+import { getIronSession } from 'iron-session'
+import { z } from 'zod'
+
+import { prisma } from '@/lib/prisma'
+import { SessionData, sessionOptions } from '@/lib/session'
+import { enforceUserRateLimit } from '@/lib/rate-limit'
+import { ACTIVE_JOB_STATUSES } from '@/lib/job-status'
+
+async function getSession() {
+  return getIronSession<SessionData>(await cookies(), sessionOptions)
+}
+
+type ActionResult<T = void> =
+  | { success: true; data?: T }
+  | { error: string; code?: number }
+
+const createSchema = z.object({
+  ideaId:   z.string().cuid(),
+  question: z.string().min(1).max(2000),
+})
+
+export async function createUserQuestionAction(
+  ideaId: string,
+  question: string,
+): Promise<ActionResult<{ questionId: string; jobId: string }>> {
+  const session = await getSession()
+  if (!session.userId) return { error: 'Niet ingelogd', code: 401 }
+  if (session.isDemo)  return { error: 'Demo-gebruikers kunnen geen vragen stellen', code: 403 }
+
+  const limited = enforceUserRateLimit('create-user-question', session.userId)
+  if (limited) return limited
+
+  const parsed = createSchema.safeParse({ ideaId, question })
+  if (!parsed.success) return { error: 'Ongeldige invoer', code: 422 }
+
+  const idea = await prisma.idea.findFirst({
+    where: { id: parsed.data.ideaId, user_id: session.userId },
+    select: { id: true, plan_md: true, product_id: true },
+  })
+  if (!idea)            return { error: 'Idee niet gevonden', code: 404 }
+  if (!idea.plan_md)    return { error: 'Er is nog geen plan voor dit idee', code: 422 }
+  if (!idea.product_id) return { error: 'Koppel eerst een product aan dit idee', code: 422 }
+
+  // Idempotency: weiger als er al een actieve PLAN_CHAT job loopt voor dit idee.
+  const existing = await prisma.claudeJob.findFirst({
+    where: {
+      idea_id: parsed.data.ideaId,
+      kind: 'PLAN_CHAT',
+      status: { in: ACTIVE_JOB_STATUSES },
+    },
+    select: { id: true },
+  })
+  if (existing) return { error: 'Er loopt al een actieve PLAN_CHAT voor dit idee', code: 409 }
+
+  const [uq, job] = await prisma.$transaction([
+    prisma.userQuestion.create({
+      data: {
+        idea_id:  parsed.data.ideaId,
+        user_id:  session.userId,
+        question: parsed.data.question,
+      },
+    }),
+    prisma.claudeJob.create({
+      data: {
+        user_id:    session.userId,
+        product_id: idea.product_id,
+        idea_id:    parsed.data.ideaId,
+        kind:       'PLAN_CHAT',
+        status:     'QUEUED',
+      },
+    }),
+  ])
+
+  await prisma.ideaLog.create({
+    data: {
+      idea_id:  parsed.data.ideaId,
+      type:     'JOB_EVENT',
+      content:  'PLAN_CHAT queued',
+      metadata: { job_id: job.id, kind: 'PLAN_CHAT', user_question_id: uq.id },
+    },
+  })
+
+  await prisma.$executeRaw`
+    SELECT pg_notify('scrum4me_changes', ${JSON.stringify({
+      type:       'claude_job_enqueued',
+      job_id:     job.id,
+      idea_id:    parsed.data.ideaId,
+      user_id:    session.userId,
+      product_id: idea.product_id,
+      kind:       'PLAN_CHAT',
+      status:     'queued',
+    })}::text)
+  `
+
+  revalidatePath('/ideas/' + parsed.data.ideaId, 'page')
+
+  return { success: true, data: { questionId: uq.id, jobId: job.id } }
+}
diff --git a/lib/rate-limit.ts b/lib/rate-limit.ts
index a1d5311..3d99843 100644
--- a/lib/rate-limit.ts
+++ b/lib/rate-limit.ts
@@ -32,6 +32,7 @@ const CONFIGS: Record<string, RateLimitConfig> = {
   'edit-idea-md': { windowMs: 60_000, max: 60 },        // grill_md / plan_md edits
   'start-idea-job': { windowMs: 60_000, max: 10 },      // Grill / Make Plan triggers
   'materialize-idea': { windowMs: 60_000, max: 5 },
+  'create-user-question': { windowMs: 60_000, max: 20 }, // PLAN_CHAT vragen
 }
 
 const DEFAULT_CONFIG: RateLimitConfig = { windowMs: 60_000, max: 10 }