diff --git a/CHAINING.md b/CHAINING.md
new file mode 100644
index 000000000..a1ac6602f
--- /dev/null
+++ b/CHAINING.md
@@ -0,0 +1,68 @@
+# Sparkle Pills Chaining Contract
+
+This repository implements an interview-first chaining flow for sparkle-pill use cases in `POST /api/chat`.
+
+## Goal
+
+For sparkle-pill requests, avoid jumping straight to a plan. First collect concrete use-case constraints, then emit an actionable system plan.
+
+## Runtime behavior
+
+1. Detect sparkle-pill intent in `query` or `message` (`/\bsparkle\s*pills?\b/i`).
+2. If required interview answers are missing, return interview questions and stop.
+3. If interview answers are present and complete, return a deterministic system plan.
+4. Do not call model providers for this branch (no Gateway or Grok dependency).
+
+## Request payload
+
+```json
+{
+  "query": "Build me a system for using sparkle pills",
+  "sparkleInterview": {
+    "useCase": "I need to manage daily focus sessions across work and school.",
+    "trigger": "Start each weekday at 08:30",
+    "tools": ["Google Calendar", "Slack"],
+    "constraints": "No notifications after 21:00",
+    "successSignal": "5 sessions completed per week"
+  }
+}
+```
+
+## Interview-first response shape
+
+```json
+{
+  "answer": "Before I design the system...",
+  "requiresInterview": true,
+  "interviewQuestions": [
+    "What exact chore or workflow should sparkle pills automate?",
+    "What should trigger each run (time, event, or manual action)?",
+    "Which tools and systems must it update (for example Calendar, Slack, email)?",
+    "What rules or constraints must never be violated?",
+    "How will you measure success each week?"
+  ]
+}
+```
+
+## Plan response shape
+
+```json
+{
+  "answer": "Sparkle Pills System Plan\n...",
+  "requiresInterview": false,
+  "provider": "sparkle-pills-planner",
+  "interview": {
+    "useCase": "...",
+    "trigger": "...",
+    "tools": ["..."],
+    "constraints": "...",
+    "successSignal": "..."
+  }
+}
+```
+
+## Files
+
+- `apps/web/src/lib/sparkle-pills.ts`
+- `apps/web/src/app/api/chat/route.ts`
+- `apps/web/src/app/api/__tests__/chat-sparkle-pills-route.test.ts`
diff --git a/apps/web/src/app/api/__tests__/chat-sparkle-pills-route.test.ts b/apps/web/src/app/api/__tests__/chat-sparkle-pills-route.test.ts
new file mode 100644
index 000000000..eb2eb8160
--- /dev/null
+++ b/apps/web/src/app/api/__tests__/chat-sparkle-pills-route.test.ts
@@ -0,0 +1,90 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+const { generateText, aiGateway } = vi.hoisted(() => ({
+  generateText: vi.fn(),
+  aiGateway: vi.fn((model: string) => model),
+}));
+
+const { grokChatCompletion } = vi.hoisted(() => ({
+  grokChatCompletion: vi.fn(),
+}));
+
+vi.mock('ai', () => ({
+  generateText,
+}));
+
+vi.mock('@/lib/ai-gateway', () => ({
+  aiGateway,
+  GATEWAY_CHAT_MODEL: 'openai/gpt-4o',
+}));
+
+vi.mock('@/lib/billing/grok-client', () => ({
+  grokChatCompletion,
+}));
+
+import { POST } from '@/app/api/chat/route';
+import { resetEntitlementStoreForTests } from '@/lib/billing/entitlement-store';
+import { resetChatQuotaForTests } from '@/lib/billing/chat-quota';
+
+describe('POST /api/chat sparkle pills interview-first flow', () => {
+  beforeEach(() => {
+    process.env.AI_GATEWAY_API_KEY = 'vck_test';
+    resetEntitlementStoreForTests();
+    resetChatQuotaForTests();
+    generateText.mockResolvedValue({ text: 'gateway reply' });
+  });
+
+  afterEach(() => {
+    delete process.env.AI_GATEWAY_API_KEY;
+    vi.clearAllMocks();
+  });
+
+  it('asks clarifying interview questions before producing a sparkle-pill system plan', async () => {
+    const request = new Request('http://localhost/api/chat', {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({
+        query: 'Build me a system for using sparkle pills',
+      }),
+    });
+
+    const response = await POST(request);
+    const body = await response.json();
+
+    expect(response.status).toBe(200);
+    expect(body.requiresInterview).toBe(true);
+    expect(body.interviewQuestions).toEqual(expect.arrayContaining([expect.any(String)]));
+    expect(body.answer).toContain('Before I design the system');
+    expect(generateText).not.toHaveBeenCalled();
+    expect(grokChatCompletion).not.toHaveBeenCalled();
+  });
+
+  it('returns a concrete sparkle-pill workflow after interview answers are provided', async () => {
+    const request = new Request('http://localhost/api/chat', {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({
+        query: 'Build me a system for using sparkle pills',
+        sparkleInterview: {
+          useCase: 'I need to manage daily focus sessions across work and school.',
+          trigger: 'Start each weekday at 08:30',
+          tools: ['Google Calendar', 'Slack'],
+          constraints: 'No notifications after 21:00',
+          successSignal: '5 sessions completed per week',
+        },
+      }),
+    });
+
+    const response = await POST(request);
+    const body = await response.json();
+
+    expect(response.status).toBe(200);
+    expect(body.requiresInterview).toBe(false);
+    expect(body.provider).toBe('sparkle-pills-planner');
+    expect(body.answer).toContain('Sparkle Pills System Plan');
+    expect(body.answer).toContain('Start each weekday at 08:30');
+    expect(body.answer).toContain('5 sessions completed per week');
+    expect(generateText).not.toHaveBeenCalled();
+    expect(grokChatCompletion).not.toHaveBeenCalled();
+  });
+});
diff --git a/apps/web/src/app/api/chat/route.ts b/apps/web/src/app/api/chat/route.ts
index 8eb126de6..d25e58b49 100644
--- a/apps/web/src/app/api/chat/route.ts
+++ b/apps/web/src/app/api/chat/route.ts
@@ -14,6 +14,7 @@ import {
   parseChatPackBinding,
   resolveChatPackGrounding,
 } from '@/lib/chat-pack-grounding';
+import { resolveSparklePillsResponse } from '@/lib/sparkle-pills';
 type ChatHistoryMessage = { role: 'user' | 'assistant'; content: string };
 
 const rawBackendUrl = process.env.BACKEND_URL || '';
@@ -136,6 +137,14 @@ export async function POST(request: Request) {
       : [];
     const query = body.query || body.message || '';
 
+    const sparkleResponse = resolveSparklePillsResponse({
+      query: typeof query === 'string' ? query : String(query),
+      sparkleInterview: body.sparkleInterview,
+    });
+    if (sparkleResponse) {
+      return NextResponse.json(sparkleResponse);
+    }
+
     if (isPro) {
       const leadScore = await scoreLeadWithJev({ query, history });
       const scoredPrompt =
diff --git a/apps/web/src/lib/sparkle-pills.ts b/apps/web/src/lib/sparkle-pills.ts
new file mode 100644
index 000000000..bde98ec00
--- /dev/null
+++ b/apps/web/src/lib/sparkle-pills.ts
@@ -0,0 +1,95 @@
+export type SparkleInterviewAnswers = {
+  useCase: string;
+  trigger: string;
+  tools: string[];
+  constraints: string;
+  successSignal: string;
+};
+
+const SPARKLE_RE = /\bsparkle\s*pills?\b/i;
+
+function compact(value: unknown): string {
+  return typeof value === 'string' ? value.trim() : '';
+}
+
+function compactList(value: unknown): string[] {
+  if (!Array.isArray(value)) return [];
+  return value
+    .map((entry) => (typeof entry === 'string' ? entry.trim() : ''))
+    .filter((entry) => entry.length > 0)
+    .slice(0, 8);
+}
+
+function parseAnswers(value: unknown): SparkleInterviewAnswers | null {
+  if (!value || typeof value !== 'object') return null;
+  const source = value as Record<string, unknown>;
+  const useCase = compact(source.useCase);
+  const trigger = compact(source.trigger);
+  const tools = compactList(source.tools);
+  const constraints = compact(source.constraints);
+  const successSignal = compact(source.successSignal);
+  if (!useCase || !trigger || tools.length === 0 || !constraints || !successSignal) {
+    return null;
+  }
+  return { useCase, trigger, tools, constraints, successSignal };
+}
+
+export function isSparklePillsRequest(query: string): boolean {
+  return SPARKLE_RE.test(query);
+}
+
+export function sparklePillsInterviewQuestions(): string[] {
+  return [
+    'What exact chore or workflow should sparkle pills automate?',
+    'What should trigger each run (time, event, or manual action)?',
+    'Which tools and systems must it update (for example Calendar, Slack, email)?',
+    'What rules or constraints must never be violated?',
+    'How will you measure success each week?',
+  ];
+}
+
+export function resolveSparklePillsResponse(input: {
+  query: string;
+  sparkleInterview?: unknown;
+}):
+  | {
+      answer: string;
+      requiresInterview: boolean;
+      interviewQuestions: string[];
+    }
+  | {
+      answer: string;
+      requiresInterview: false;
+      provider: 'sparkle-pills-planner';
+      interview: SparkleInterviewAnswers;
+    }
+  | null {
+  if (!isSparklePillsRequest(input.query)) return null;
+
+  const interview = parseAnswers(input.sparkleInterview);
+  if (!interview) {
+    return {
+      answer:
+        'Before I design the system, I need a short use-case interview so the workflow stays concrete and executable.',
+      requiresInterview: true,
+      interviewQuestions: sparklePillsInterviewQuestions(),
+    };
+  }
+
+  return {
+    answer: [
+      'Sparkle Pills System Plan',
+      '',
+      `1. Objective: ${interview.useCase}`,
+      `2. Trigger: ${interview.trigger}`,
+      `3. Integrations: ${interview.tools.join(', ')}`,
+      `4. Guardrails: ${interview.constraints}`,
+      `5. Success metric: ${interview.successSignal}`,
+      '6. Execution loop: intake -> validate context -> run actions -> confirm outputs -> log weekly feedback.',
+      '7. First rollout: ship one low-risk automation path, then expand after two stable weekly cycles.',
+    ].join('\n'),
+    requiresInterview: false,
+    provider: 'sparkle-pills-planner',
+    interview,
+  };
+}