Thread · HN Continuity

What would a serious security model for an agent even look like?

I'm sure I've already got a dozen people reaching for the reply button, but slow down there, cowboy. I don't think it's even remotely as easy to define as people think. We have a reasonable concept of how to lock them down really tightly, no question, and I expect that most of the answers in the "leap to mind" category match that.

But let's say we'd like them to continue functioning the way they do today. I want my agent to be able to hit the web. I want my agent to be able to read out of its assigned directory sometimes. I want it to be able to hit external resources through MCP servers that have no pragmatic way to know what's going on. And probably most importantly of all, I want my AI to be able to grab from three distinct sources, each of which may be nominally safe on its own, and combine things in a way that may make each of those nominally safe things become unsafe. For example, any ability to read a local file and make a remote request becomes a potential exfiltration mechanism, especially when you remember all the sidechannel ways communication can occur.

I agree that shifting everything on to the user is essentially non-functional. But whereas I feel like I have a reasonable answer to a lot of other security-related problems, it isn't even clear to me what the definition of a secure agent is.

There's an effect I need to put a name on someday, where you can get 10 people in a room to agree to a certain series of words, and they will all leave the meeting thinking they agree, but in fact there is no agreement at all because they all have a different definition of the words that were used. In this case, everyone here is going to go "Oh, yes, certainly, AI agents should be secured." But if you sit down with 10 of us to really do the work of defining exactly what that is, you're going to get 10 different answers. There will be overlap, certainly, but when you get down to the nitty-gritty questions like "OK, the user has explicitly asked the agent to do X by accessing Y and the agent has done so and determined that they need to do Z, which the user clicked "allow all" for, and now the agent has decided that it wants to do T, is T fully covered under that "allow all" or not?" you're not going to get anything like universal agreement across the huge range of Xs, Ys, Zs and Ts that could happen and are relevant... and that's still just one question! It's not the totality of what constitutes a "secure agent".

Defining what a "secure agent" even is is really hard because when it comes to agents, the things that fill in the variables are as arbitrarily complicated as human actions. I haven't fully worked this out but it might be reasonable to say that "agent security" is in reality Turing complete, what with the way they so often throw out fully-fledged programs that you have to approve or reject permissions for.