Strategic Health Guides — Full Dissection

1. Write your guide first. 8,000–12,000 words, structured (see Guide Anatomy below). The guide IS the product — the AI just makes it conversational.
2. Turn it into text. Extract clean text from your doc/PDF. This becomes your knowledgeContent. Keep it as one text blob per guide.
3. Database tables (Convex):

   guides:      { title, price, content, symptomList, supplementList }
   profiles:    { userId, conditions, goals, meds, lifestyle }
   sessions:    { userId, guideId, title }
   messages:    { sessionId, role: "user"|"coach", text }
   usage:       { userId, month, messagesUsed, limit }

4. Intake form. Onboarding asks 5–10 questions (conditions, goals, meds, lifestyle). This is what makes the coach feel "personalized" — it's cheap and it's exactly what they do.
5. The coach function (a Convex action — this is the entire AI):

// convex/coach.ts — the whole brain, ~30 lines
export const sendMessage = action(async (ctx, { userId, guideId, text }) => {
  const usage = await getUsage(ctx, userId);
  if (usage.used >= usage.limit) throw new Error("Message limit reached — upgrade!");

  const guide   = await db.get("guides", guideId);       // the whole book
  const profile = await db.get("profiles", userId);       // personalization
  const history = await lastNMessages(ctx, userId, 20);   // conversation memory

  const reply = await callAI([{
    role: "user",
    content: `You are a health coach. Answer ONLY from the guide below.
Be specific and action-oriented. Never diagnose. Suggest questions
for their doctor when appropriate.

=== GUIDE ===
${guide.content}
=== MEMBER PROFILE ===
${JSON.stringify(profile)}
=== QUESTION ===
${text}`
  }]);

  await saveMessage(ctx, userId, reply);
  await bumpUsage(ctx, userId);
  return reply;
});

6. Chat page. Simple: message list, input box, "X of Y messages left" counter, upgrade button at zero. (Copy their counter-as-paywall pattern — it works.)
7. Stripe hookup. Your existing subscription webhook sets usage.limit = 100 and resets the counter monthly. Free users get 30 total.
8. Daily nudge (their retention secret). A Convex cron job fires each morning: generate a personalized "today's focus" message from their profile + guide. This is what brings members back daily.
9. Lock the content down. Serve guide.content ONLY from inside the server function — never to the browser. (Their site leaks it publicly — don't repeat that mistake.)
10. Guardrails. Put a permanent "educational only, not medical advice" line in the system prompt + on screen. Tell the AI to decline dosing questions for pregnancy/children and to refer to a doctor.