Design a deep research agent that answers complex questions by searching and synthesizing many sources.

The modern agentic system-design question. The signal is the plan, search, read, synthesize, verify loop with per-claim citations, plus keeping cost and latency bounded. The hard parts are not the writing.

Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.