World Model
A neural network that predicts future sensory observations given current observations and actions, simulating how the world will respond to a robot or agent's behavior. Enables planning without physical interaction: 'imagining' the consequences of an action before executing it. In robotics (1X Technologies, DREAMER), world models enable real-time planning. In LLM agents, they underpin speculative execution and lookahead search.
In practice
An agent tasked with moving objects on a table can use a world model to internally simulate thousands of action sequences and select the one with the highest probability of success before moving the physical arm. For LLM agent developers, an implicit world model is built by maintaining a structured 'state scratchpad' that the model updates at each step — a technique used in systems like Voyager (Minecraft) and in planning agents with tool use.