Questions, for people who've actually done this:
Have you let an agent spend money, or nearly, in the last few months? What was bought, and how did payment work?
What do you use to limit it (provider hard caps, a particular card, something you built)? What does it miss?
Did anything go wrong, or did you give up on a task because of payment?
Disclosure: I'm Tom, based in Australia. I'm exploring whether a service in this area is worth building. It's early research. I have no product, customers, partners or security claims to show, and I'm not selling anything. If you're willing to chat for 15 minutes about what you've actually done, reply here and I'll message back; I'll keep notes anonymous.
With in minutes it had spent all the budget buying fake follows on an X account that was similar to mine.
Lessons learnt: Most checkout pages have strong anti bot / fraud protection it struggles to get past. Most checkouts require an account which it struggles to register. It can't budget, if you give it money to spend, it will do as you ask and go to work spending it. It doesn't really know what it needs. It wanted to buy a vps despite already having access to a large dedicated server. It doesn't understand value. It wanted to buy the most expensive package because it offered the most features, it through that means its the best value.
In my case I gave it an email account it could sign up with and then used the bitcoin cli to make the payment.
It had its own wallet so it couldn't spend more than what was in it. I didn't want to limit it to for example $10 a day because I wanted it to be able to buy in bulk. Most advert space will be like $70 for a week not $10 a day. So I thought a daily limit would not work unless I put a large budget behind it.
It misses the entire point of money tbh. It just doesn't understand it.
Creating accounts and fraud protection are the biggest issues tbh. We need an alternative to captcha. Something that protects registration and checkout pages from abuse but can still be solved by agents. If you solve that issue the rest is already solved, just give it a credit card or crypto account. Most corporate cc providers allow you to put limits and alerts on the cards.
In a few years that will be the norm but for now I think agent marketplaces are the best solution. Instead of trying to work around bot protection on ebay just make an agent friendly ebay. That's what I am building.