As AI agent systems grow in complexity, understanding their runtime behavior becomes a major challenge. Traditional documentation often lags behind rapid code changes. This post introduces Harness Handbook, a novel approach that auto-generates a three-level documentation system from the codebase, centered on runtime behavior. It organizes implementation details by execution phase, state flow, and source location, making it easier for both human developers and coding agents to navigate, understand, and modify complex agent harnesses. The system aims to solve the 'behavior location' problem, where developers struggle to find where specific runtime actions occur. For teams building or maintaining sophisticated agent frameworks, this offers a practical way to keep documentation in sync with evolving code. The approach could become a best practice for AI system documentation.
Harness Handbook proposes a three-level, auto-generated documentation system for AI agent harnesses, focusing on runtime behavior to improve navigation and maintainability.