Part 4 of the Harness Engineering series. Tools are the model's surface area into the world. Here's what they are, why they exist, and how to tell a well-designed tool surface from a badly-designed one.

Part 4 of the Harness Engineering series. Tools are the model's surface area into the world. Here's what they are, why they exist, and how to tell a well-designed tool surface…

Part 5 of the Harness Engineering series. The context is everything the model gets to see on a given API call — and every turn requires you to assemble it fresh. Here's why…

Part 6 of the Harness Engineering series. The Environment is the runtime tools operate inside — filesystem, shell, network, resources. Here's why every tool with side effects…

Part 8 of the Harness Engineering series. Observability turns "I built an agent" into "I built an agent I can actually operate." Here's what it is, why non-deterministic…