Run extension script on startup?

[Alan Lord (News)]

I have an extension for TB3 which needs to "sign-on" to a remote CRM and
get a session id to maintain a connection for a period of time.

The sign-on process works fine, but it requires the user to click a
button or otherwise intervene.

Can I get the sign-on script to fire when TB3 is first started? If so how?

Assuming my function is called sign-on() {} I assume there is an event I
should be listening for or something to fire it?

Also, is this reasonable practice to want to do this?

TIA

Alan