What are AI Agents, Really? › The Core Metaphor: Agents Are State Machines

To understand agents, it helps to first understand the concept of a state machine. ## What is a State Machine? A state machine is a system that: - Is always in one of a finite number of states - Moves between states based on inputs - Executes logic within each state ## Deterministic vs. Non-Deterministic - Deterministic: A given state and input always leads to exactly one next state, similar to a vending machine. - Non-Deterministic: A given state and input can lead to multiple possible next states, like a choose-your-own-adventure game. Agents fall into the second category. They are non-deterministic state machines, because LLMs can produce different results for the same input. This variability adds flexibility, creativity, and adaptability. <Figure src="/images/content/Example_of_a_Turing_machine.svg" alt="State machine of the Nondeterministic Turing machine" caption="State machine of the Nondeterministic Turing machine" invertOnDark={true} /> If you want to understand why LLMs are non-deterministic, see [this article](/writing/why-llms-are-not-deterministic).