Program
A set of instructions a computer can carry out. Your browser is a program, and so is the agent you talk to. A program sits in a file doing nothing until something starts it.
What an agent can really do is start programs: ones that run tests, ones that install things, ones that delete. Each does exactly what it does, whatever the agent intended, so a command deserves more of your attention than a sentence.
Say it to your agent
“Before you run that program, tell me in one sentence what it does and what it changes on my machine. If it deletes or overwrites anything, stop and ask me.”