Here are programming tips on 1st and 2nd generation Toyota Prius when lost all keys.
Prius Gen1 (1997-2003)
Gen1 Prius (2001-2003) no all keys lost via OBD.
Prius Gen2 (2003-2009)
If it is non smart key, do the same way as Gen1. Read eeprom and write key.
If it is smart key, you can do it by OBD and reset the smart ECU.
Using tools like Autel IM608 or smart pro. Also you can program with a cracked version of techstream via OBD, same process. Reset smart ECU and follow the prompts
IM608 supports Toyota Prius smart system year 2004-2009 add key and all keys lost by OBD.
smart pro aint touching this via obd.