I want to keep call's key notes of a each user, to be used for the next call of same user. i tried to pass Vapi analysis Summary prompt the previous key notes i kept inside my DB. for example i add to the Summary prompt the info from my DB as [old_key_notes]. But it looks like it is not passing such info to the Summary prompt. only if i write manually to the Summary prompt the old key notes it is working fine. Any suggestions?