But it never starts doing anything until someone or something prompts it. It doesn’t even exist until you ask it to do something.
It is autonomous in the sense it can continue to function without supervision after the operator has started it, in the same way countless programs on your computer are “autonomous”.
But it can never choose to begin doing something at any time of its own volition. It does not have “autonomy” like a human does.
You are conflating creation and instruction. Your birth is analogous to the creation of an LLM model. Your subsequent actions are a consequent of your bodily compulsions, tampered by your environment. The LLMs actions are governed by what it is trained to perform. No one has full autonomy of their lives, but I would argue that LLMs have none at all.
Autonomous just means that a system is self-controlled rather than externally controlled. It is the name used for robots when they are wholly controlled by on-board software rather than external commands or remote control.
Something like NASA's Mars rovers are considered as semi-autonomous since they do receive external instructions, but then execute those instructions autonomously without further intervention. Similarly the combination of a coding agent and the LLM it connects to would best be considered as a semi-autonomous system.
You could also have a fully autonomous robot, or just agent, powered by an LLM, where it's not taking external instructions, but rather reacting to external events in some internally proscribed way.
It is autonomous in the sense it can continue to function without supervision after the operator has started it, in the same way countless programs on your computer are “autonomous”.
But it can never choose to begin doing something at any time of its own volition. It does not have “autonomy” like a human does.