If you authorised an agent to act on your behalf, you are entirely responsible for their actions providing they acted within the bounds of authority you gave them.
Regardless, OPs software (his AI agent) isn't a legal entity and OP is entirely responsible for the software he chooses to use. Clamming the software is responsible for his actions (a software bug) isn't going to stand up in court. Whilst OP could claim damages for being provided with faulty software I suspect this will be very difficult to say the least; the authors of the AI agent will make the (very good) defence that their software was used incorrectly.