Picking a model is the easy part. Production AI needs an entire layer below it — the parts that catch failures, control costs, monitor drift, and keep the system reliable when the load is real.
A Evaluation harnesses
Test sets that cover edge cases, regression detection on every model or prompt change, automated checks for hallucinations and policy violations. Catch failures before users do.
B Observability and alerting
Per-request traces, token usage by endpoint, accuracy and drift dashboards, alert thresholds on cost, latency, and error rates. The same operational discipline you have on the rest of your stack — applied to AI.
C Cost and scale architecture
Model routing (cheap models for cheap queries), prompt caching, response caching, context window management, batch inference where it makes sense. The difference between a $50K/month bill and a $5K/month bill is engineering, not pricing.
D Reliability engineering
Retry logic, fallback models, graceful degradation, rate limit handling, circuit breakers, multi-provider failover. The boring infrastructure that turns an AI demo into a system you can put your name on.