AI system design

Beginner — What questions come before architecture?

• What task should succeed, which data is authoritative, who may access it, what errors are costly, how fast it must respond, expected load, and available budget.
• Then decide whether deterministic code or AI is needed.

Intermediate — How do you scale agent traffic?

• Estimate provider/tool call amplification, use admission controls and tenant quotas, isolate background work, and scale workers to real dependency capacity.
• More API replicas do not remove provider token limits or serialize conflicting thread updates automatically.

Senior — How do you design degraded behavior?

• Define acceptable alternatives per task: verified templates, search results, paused durable work, or staff escalation.
• Preserve data/permission/quality contracts and distinguish missing evidence, service failure, and unknown commit outcomes explicitly.

Scenario — Design an insurance assistant in two minutes.

• Use Next.js and an authenticated Node API, a bounded intent router, policy RAG, and authorized claim tools.
• Put draft validation, exact approval, and idempotent submission in deterministic services/workflows.
• Add scoped memory, durable state where needed, redacted tracing, source/outcome evaluations, and per-tenant budgets.
• Start with one assistant; justify any extra agents or MCP integration through real requirements.