by Databricks Staff
An AI agent harness is the software infrastructure that wraps around a large language model (LLM) and enables it to act on tasks, not just respond to prompts. The model reasons through a problem and decides what to do next. The harness connects it to the tools, systems, memory and execution environments needed to carry out those actions.
Agent = Model + Harness
Think of the model as the “brain” that generates reasoning and decisions. The harness is everything around it that helps the agent operate safely and reliably, including:
Without a harness, a model can answer questions, but it can’t reliably run code, call APIs, access files, remember prior work or complete multi-step workflows on its own.
