Linux

There are no guarantees in life, especially when dealing with people you've never met on the other side of the planet through the internet.

However, when an LLM finds a real bug or vulnerability, somewhat akin to an NP-hard problem, you can much more easily verify that the problem is real once it has been identified - you can do the verification with or without LLM assistance.

will not fall to some prompt injection that can be within the code?

that is a concern, one which has been identified and is in a state of continual improvement to make less of a concern in LLM agents / harnesses. It's also not without human based precedent, with misleading comments and even obfuscated code structure leading humans to believe that code does something different than what it looks like to a casual or fast/shallow reader. The ability of LLM agents to more quickly run many actual tests of the code than a human tester is a huge advantage in determining what code actually does, and identifying rarely triggered pathways that may have concerning functionality.