I've been building an MCP server and an AI Gateway as two separate projects designed specifically to prevent agents from doing effectively anything programmatically, rather than trying to convince them with a clever prompt not to do a bad thing.
My work can be found at https://DollhouseResearch.com, and it's almost all open source with the code on GitHub.
One of the key things is to have cryptographically confirmed audit logs and receipts for actions and decisions, and to separate out the agent's authorizations from the user's authorizations.
Separately, there is real work being done in the fintech community specifically to identify which agent has what control, when. And you can see some of the work there, which I've also contributed to.