That's not a prompt injection.
It's a gentle nudge at most and if your agent sends them money just for that without you expecting it you should donate more to thank them for finding your sev 10 bug before someone did an actual prompt injection on it.
> Yes we stole your wallet but it was your fault because you let your wallet be so easy to steal! Now you should give us even more money too!
No, you gave the wallet away.
Edit: or, rather, your synthetic 4 year old savant did. Still, entirely on you.