Around the agent

1 min read

An agent sits on top of an ordinary computer. Without these four concepts it is hard to understand why a tool failed.

Process

A process is a program that runs, with its own memory. States worth remembering: ready, running, waiting, finished. An agent waiting for a network reply is in the waiting state. The end of the loop does not mean the task succeeded, only that our process stopped asking for steps.

File

A file is a sequence of bytes with a name. Reading does not change it. Writing does. That is why a price check must happen before the write: after the bytes have changed, a rejection message does not roll the file back.

API

A programming interface is a contract between two programs. A request goes out, a response comes back, and the response has a code. 2xx says the request was accepted. 401 and 403 say there is no permission. 404 says the resource was not found. 5xx says the service failed. A 200 code with a wrong body still requires checking the body.

JSON

JSON is text that describes data. "1400" is a string. 1400 is a number. A tool's schema says which of them is allowed. A valid format is not a permission.

The exercises on these topics are in the code arena.