Two Kinds of AI Agents (And Why You Need Both)

Persistent context agents vs. stateless decision functions. When to build which, how to evaluate each, and why the industry is conflating two fundamentally different problems. Andrej Karpathy ended his 2025 Year in Review with this: "I don't think the industry has realized anywhere near 10% of their potential even at present capability." I think the reason is that we're treating "AI agent" as one category when it's actually two. And the evaluation strategies, architectures, and failure modes are