automatic tool change without prompt

How do I configure axis to execute automatic tool change without the prompt to insert the next tool?
I'm running a lathe with gang setup and would like it to be fully automatic.

Thanks JT. I'll look at my hal. If you or anyone has a an example what I need to add that would be great. I'm in the middle of my 1st job on this machine
How are gang tool changes typically handled in linuxcnc? I have not specified a carriage return position for changes. In my current manual mode the changes happen close to the part which is efficient and I'd like to keep that this way for now but a tool change home position may be safer in the future....

TIA