The Anatomy of an Agent Harness

An AI agent is defined as the combination of a model and a "harness," which encompasses all the code, configuration, and logic that makes the model's intelligence useful. The harness provides essential capabilities that models lack out-of-the-box, such as durable state, tool execution, and access to real-time knowledge. Key components of a harness include filesystems for storage, bash and code execution for general problem-solving, and sandboxes for safe, isolated environments. Harnesses also manage context to prevent performance degradation and enable agents to complete complex, long-horizon tasks autonomously by providing mechanisms for memory, verification, and collaboration.