Is accessing session variables from per-request subroutine possible?

Thank you Nolan.

Your solution works. It creates a logon prompt for the OTP as the password. This is still a prompt for a user to enter a "password" although it is an OTP. I can successfully pass the user name but not the originating session.logon.last.password from the access-policy.

I have tried many methods without success (per-request policy; subroutine, subroutine macro, access policy). Either I haven't found the right combination or it doesn't work this way by design.

mcget -secure {session.logon.last.password}

mcget {session.logon.last.password}

subsession.logon.last.password

I am also trying other avenues such as using iRule LX to submit the request to the MFA API. I was just hoping radius would be an easier route.