Agent Tool Design

The interface the LLM sees is not the same as the interface a human sees.

Tool interfaces for LLMs (the Agent-Computer Interface, ACI) serve the model's reasoning process, not a human's memory. The north star is poka-yoke: design out misuse so the error cannot happen.

Framing — The ACI Model

HCI (Human-Computer Interface) is designed for human memory, attention, and error recovery. ACI is designed for a model that reads everything in one pass, mid-task, with limited attention to spare.

Three consequences: