Are variable valid for that session or global?

[VincentEmmanuel]

I am trying to understand about the use case of variables in my chatflow. I understand that we create the variables and then assign some values to them in the custom tools. So my question is, the values are good for the session or globally because I was thinking of using it as a placeholder for my custom tool value like customer name, customer contact, etc which is only valid for that particular session and I could pass these values from tools to tools to process data, update database , etc.

I can imagine having a few sessions going on at any one time so a session based variable is something I am looking for.