Calling a function pauses the code that called it. The panel on the right of the next instrument lists what is running, newest first. That list is called the call stack, and it will matter later.
Parameters and return values
Also called Arguments
Parameters are the inputs a function asks for, named in its brackets. The values you pass in are the arguments. return hands one value back to the caller and ends the function, and a function with no return hands back undefined, JavaScript's word for nothing.
A function's parameters and return value are its promise to the rest of the code. When an agent changes them, every caller is affected, including the ones it didn't read.
“You changed the parameters of createOrder. Run rg -n "createOrder\(" src/ and list every call site, then confirm each one passes the new arguments in the right order. Show me the list.”