In an interview a while back, after the usual rounds, the interviewer leaned into a question I thought I had a good answer for: You build agents. How do you test them? I said what everyone says. An
Part four of a series on agent harnesses. The earlier pieces covered the model-plus-harness idea, subagents, and sandboxes. This one is about the three things that turn a capable agent into one that e
Part three of a series on agent harnesses. Part one introduced the model-plus-harness idea, and part two split work across subagents. This piece is about the layer where agents stop just talking and s
Part two of a series on agent harnesses. If you have not read part one, it introduces the idea that an agent is a model plus the harness around it. This piece builds on that, so a quick skim first wil
If you have ever called an LLM API, you already know the basic shape of it. You send some text, you get some text back, and the connection closes. That is a model. It is good at producing language, bu
