The setup itself is absurd. They gave their model full access to their Stripe account (including the ability to generate coupons of unlimited value) via MCP. The mitigation is - don't do that.
If my employee is prone to spontaneous combustion, I don't assign him to the fireworks warehouse. That's simply not a good position for him to work in.
I think you’d set the model up as you would any staff user of the platform - with authorised amounts it can issue without oversight and an escalation pathway if it needs more?