I mean, ideally enforce W ^ X, and enforce stricter permissions on executables where the agent has flipped the W to X. My broader point is we should be using operating system primitives instead of regex and wishful thinking.
You can't give shell access and then revoke special parts of it. This is not controversial.
All your criticisms apply to all LLM harnesses - and everyone who genuinely cares about these things is using security on top of the harness, because OBVIOUSLY.
This doesn't require cooperation from the shell. If writable paths are non-executable, and executable paths are non-writable, then executing `cp $(which git) my-new-favourite-binary` doesn't grant you permission to run it.
The part which does require cooperation (from outside of the shell, i.e. from the harness) is the ability to upgrade writable paths to executable, at the cost of writability and whatever other restrictions you place on the binaries generated by your agent.
This kind of W^X invariant is widely deployed in every desktop operating system, and the type of W-X upgrade hook I described is used by every JIT engine.
> You are confusing CPU-level security with filesystem-level security.
> I'm curious - how do you expect an LLM harness to build and test executables without being able to build and execute executables?
W^X applies to file systems as well as page tables, and this is called out in paragraph 4 of the Wikipedia article you didn't read. Respectfully, I'm leaving this conversation at this point because it doesn't seem productive.
You did not hit max depth - you hit a timer designed to prevent rage posting.
My question stands - if you accept that LLM harnesses are designed to allow the building and testing of executables - how do you imagine you can prevent the building and running of executables?
Going from "build and running executables" to that needing to be done on the same system and under control of the LLM is a large leap.
Separation of duties and ephemerality are well-known security mechanisms that many harnesses jump right over in the pursuit of easier UX.
Mingling permissions + trusting vibe-coded security boundaries in the harness itself (developed by folks whose appetite for risk would make even an 00s front-end developer blush) is rolling a handful of dice all at once.
But fundamentally, this is a disagreement between two risk appetites who will never agree: {it works most of the time} vs {it's guaranteed to never fail}
It does not need to be on the same system - but that is currently how it is done by nearly everyone in the field because it seems to be the most effective way. Which is why coding harnesses build AND execute code.
I'm not sure why you disbelieve agents can do "guaranteed to never fail". Proving correctness is one of their strengths. Proofs in general, in fact, much much better than the typical human coder.
You can't give shell access and then revoke special parts of it. This is not controversial.
All your criticisms apply to all LLM harnesses - and everyone who genuinely cares about these things is using security on top of the harness, because OBVIOUSLY.
Your complaints are misguided.