alt Hacker News> There is no grammar you can restrict LLMs to; for a system like this, the semantics are total and open-ended. It's what makes them work.
You're missing the point.
An agent system consists of an LLM plus separate "agentive" software that can a) receive your input and forward it to the LLM; b) receive text output by the LLM in response to your prompt; c) ... do other stuff, all in a loop. The actual model can only ever output text.
No matter what text the LLM outputs, it is the agent program that actually runs commands. The program is responsible for taking the output and interpreting it as a request to "use a tool" (typically, as I understand it, by noticing that the LLM's output is JSON following a schema, and extracting command arguments etc. from it).
Prompt injection is a technique for getting the LLM to output text that is dangerous when interpreted by the agent system, for example, "tool use requests" that propose to run a malicious Bash command.
You can clearly see where the threat occurs if you implement your own agent, or just study the theory of that implementation, as described in previous HN submissions like https://news.ycombinator.com/item?id=46545620 and https://news.ycombinator.com/item?id=45840088 .
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> propose to run a malicious Bash command
I am not sure it is reasonably possible to determine which Bash commands are malicious. This is especially so given the multitude of exploits latent in the systems & software to which Bash will have access in order to do its job.
It's tough to even define "malicious" in a general-purpose way here, given the risk tolerances and types of systems where agents run (e.g. dedicated, container, naked, etc.). A Bash command could be malicious if run naked on my laptop and totally fine if run on a dedicated machine.
You seem to be saying "I want all the benefits of YOLO mode without YOLO mode". You can just… use the normal mode if you want more security, it asks for permission for things.
> Prompt injection is a technique for getting the LLM to output text that is dangerous when interpreted by the agent system, for example, "tool use requests" that propose to run a malicious Bash command.
One of the things Claude can do is write its own tools, even its own programming languages. There's no fundamental way to make it impossible to run something dangerous, there is only trust.
It's remarkable that these models are now good enough that people can get away with trusting them like this. But, as Simon has himself said on other occasions, this is "normalisation of deviance". I'm rather the opposite: as I have minimal security experience but also have a few decades of watching news about corporations suffering leaks, I am absolutely not willing to run in YOLO mode at this point, even though I already have an entirely separate machine for claude with the bare minimum of other things logged in, to the extent that it's a separate github account specifically for untrusted devices.