The first seven articles built the mental model. This one is how to turn a working demo into a product.
1. Define the Problem, Not the Tech
❌ "We need RAG"
✅ "Support answers 200 repetitive product questions daily—60% of time.
Goal: automate 80% of repeats."
Quantify first, pick tech second. Many failures solve problems that don’t exist.
2. Start with the Smallest Scenario
V1:
- 1 data source (FAQ)
- 1 user type (internal support)
- 1 question category (product features)
Not V1:
- 10 sources × 5 user types × all questions
The 20% of features serving 80% of users is your MVP.
3. Build an Eval System
No eval = no idea if you improved.
Offline:
- 50–100 question + gold-answer pairs
- Re-run on every prompt/model/RAG change
- Metrics: accuracy, relevance, hallucination rate
Online:
- thumbs up/down
- weekly human spot-check (20 samples)
- business metric: ticket volume down?
4. Layered Hallucination Defense
Layer 1: prompt — "answer only from provided materials; say unsure if not covered"
Layer 2: RAG citations — every answer links sources
Layer 3: confidence gate — low confidence → human
Layer 4: human review — medical, legal, finance
One prompt cannot solve hallucination—defense in depth.
5. Cost Estimation
Cost per turn ≈ (input tokens + output tokens) × price
Example (GPT-4o):
2000 input × $2.5/1M = $0.005
500 output × $10/1M = $0.005
≈ $0.01 per conversation
1000 DAU × 5 turns = 5000/day → ~$50/day → ~$1500/month
Optimizations:
- small model for easy queries (10× cheaper)
- cache frequent answers
- RAG to shrink input tokens
- per-user daily limits
6. Security Red Lines
| Risk | Mitigation |
|---|---|
| Prompt injection | input filtering + system prompt isolation |
| Data leakage | no secrets in prompts; authenticated APIs |
| Over-permissioned agents | least privilege on tools |
| Harmful output | moderation APIs + filters |
| Vendor lock-in | backup models; don’t 100% depend on AI for critical paths |
7. Monitoring and Alerts
After launch, track:
- latency (P50, P99)
- error rate (timeouts, 5xx)
- token usage (daily trend, spikes)
- user feedback (negative rate)
- hallucination detection (if automated)
8. UX for AI Products
Different from traditional software:
- Show uncertainty: “Answer based on handbook v3.2—contact support if unsure”
- Allow correction: “Was this helpful?”
- Graceful fallback: human handoff—not “Error 500”
- Streaming: long answers stream so users see progress
9. Iteration Cadence
Weeks 1–2: MVP (one scenario + basic RAG)
Weeks 3–4: feedback → prompt + retrieval tuning
Month 2: more sources + eval harness
Month 3: data-driven choice: fine-tune? add agent?
Don’t boil the ocean. AI products improve with usage data.
10. Team Skills
| Role | Needs |
|---|---|
| Product | scenarios, eval criteria, UX |
| Engineering | RAG pipeline, APIs, deploy, monitor |
| Domain expert | test data, quality review |
Minimum viable team: 1 full-stack engineer + 1 domain expert → MVP in ~2 weeks.
Full Checklist
□ Clear problem and metric
□ Small MVP scope
□ 50+ test cases
□ At least two hallucination layers
□ Cost estimate + optimization plan
□ Security review done
□ Monitoring live
□ UX fallback designed
□ Iteration plan written
□ Roles assigned
Series Recap
Eight articles from “what is AI” to production:
Concept → Mechanism → Prompt → RAG → Agent → Architecture → Multimodal → Production
Lv.1 Lv.2 Lv.2 Lv.3 Lv.3 Lv.4 Lv.4 Lv.5
AI moves fast; these frameworks age more slowly. New models ship—you’ll still know what changed for you.
This series will keep growing as we learn.