Explain the basics of reinforcement learning (and how it differs from supervised learning).

RL underpins RLHF, robotics, and recommendation, and interviewers want the core framing. The signal is the agent-environment-reward loop and the three things that make it harder than supervised learning. Here is the answer.

Updated Aug 2026 · Grounded in real Applied AI Engineer interview loops and written to a senior-engineer editorial bar.