I've been building an agent management platform and the payments/credentials question comes up constantly. Our approach has been to separate 'what the agent knows' from 'what the agent can do' -- agents have their own credential stores with platform-specific OAuth tokens, API keys, and account details, but the execution layer is sandboxed.

For spending money specifically, the pattern that seems safest is: agent proposes action with cost estimate, human approves via a notification (Telegram, email, etc.), then the backend executes the actual payment call. The agent never touches raw card data. Prepaid virtual cards with low limits are probably the most pragmatic path for autonomous spending today.

Re: your question about trusting an agent with $500 -- I'd trust it with $500 in API credits (worst case: wasted compute), but $500 on an e-commerce site is a different risk profile entirely because you can't easily reverse a physical goods purchase.

The Visa/Mastercard announcements are interesting but feel premature. The missing piece is standardized agent identity and capability declarations -- something like 'this agent is authorized by user X to spend up to $Y on category Z'. That's more of an identity/permissions problem than a payments problem.

I haven't tackled payments, but I've run an agent with SSH access to a production server and real API keys for a few weeks. The trust question you're circling ("would you trust an AI with $500") is the interesting part. My answer so far: yes for reversible actions, not yet for irreversible ones. Deleting a file, sending an email, making a payment — these need a different approval model than reading a database or running a query. The hard problem isn't capability, it's building infrastructure that distinguishes "can do" from "should do without asking.

And i want to build an agent capable to do automated investment. so, to the question "has" anyone...?" i believe yes, my role model is Jim Simons from Renaissance. He did.

Many companies that have virtual cards as a service are hesitant to give agent access until the company shows reliable volume. You could add it yourself to your agent or hire a human to take care of it.

Been building unwall.xyz

We've been running AI agents that spend real money autonomously — not on physical goods, but on API credits, compute, and social media placements. A few observations from what actually breaks vs. what you'd expect:

The failure mode people worry about: "agent goes rogue, spends $10k." The failure mode that actually happens: agent makes a confident decision on stale context. It runs a task that was valid 3 hours ago but is now redundant. Or it retries a failed payment 5 times because the failure was ambiguous. The damage is $20 of wasted API credits, not $10k — but the lesson is the same. Budget guardrails matter, but freshness checks matter more.

On the approval gate question: we use a pattern similar to agentsbooks' — agent proposes, human approves for anything irreversible. But in practice, the approval friction kills the value of autonomy. What actually works is pre-authorizing a class of actions ("spend up to $50/week on content distribution") rather than approving individual transactions. The trust unit is the policy, not the payment.

Re: your specific blockers — the 3DS problem is real and I don't think there's a clean developer solution today. The browser automation legal risk (Amazon v. Perplexity) is worth taking seriously. Virtual cards with per-merchant limits are probably the least fraught path for a while.

The Visa/Mastercard moves are interesting but I'd bet the real unlock is when businesses start issuing agent-specific cards with embedded policies rather than trying to retrofit consumer card rails. That's a few years out.