Agent harnesses are the glue between your application and a large language model. This guide breaks down how they work, from setting up base URLs and API keys to managing the conversation flow. Understanding this architecture is crucial for developers who want to integrate new models quickly or build custom agent behaviors. The post covers practical aspects like configuration and testing, making it a useful reference for both beginners and experienced engineers. As AI models evolve rapidly, knowing how to swap them in and out of your agent harness becomes a key skill. This guide provides a clear foundation for that process, helping you avoid common pitfalls and make informed decisions about your agent stack.
Explore how agent harnesses communicate with large language models, from configuration to interaction patterns, and what it means for developers building or using coding agents.