Before the end of 2026, these ten AI terms are worth understanding

From “harness” to “prompt injection”, behind these words is the way AI systems are built today. Each word is accompanied by a real example.

The body outside the brain: harness

If you only learn one new word this year, you will learn harness.The model is responsible for predicting the text, and the harness is responsible for the rest. It runs a loop: it prompts, executes the tool calls required by the model, and then feeds the results back to the model. Context, state, and security are also under its control. In an article published on O’Reilly Radar in July 2026, Hugo Bowne-Anderson compared the model with the “brain” and the harness the “body”, and listed the above five responsibilities one by one. Now, a shorthand is very popular in the circle of engineers: Agent = Model + Harness.

The core is not that big. Bowne-Anderson pointed out that executable programming agent loops only need 131 lines to write in Python, while search agents based on the same loop only need 61 lines. The really hard thing is to wrap it outside the loop. He presented, for example, a customer service agent for women’s health services. The main agent assigns each request to a full-time…