Generative artificial intelligence models, or GenAI, are trained to create content. This includes text, summaries, images, or code, for example. One particularly well-known type is the large language model, or LLM, known from applications such as ChatGPT by OpenAI, Anthropic Claude, or Google Gemini.
An LLM is specialized in processing and generating human language. It can evaluate unstructured information such as news, documents, or free text, and generate natural-language texts such as summaries, draft decisions, or documentation.
Agentic AI systems go one step further. They combine generative AI, often LLMs, with structured process steps, roles, permissions, clearly defined subtasks, control mechanisms, and system integrations. This control layer is often referred to as the agent harness.
If modern AI is the engine, then the agent harness is the rest of the vehicle: steering, brakes, and navigation. It turns a language model into an agent that can act in a controlled way.