You're joking, right? There's nothing "reasonably consistent" about LLMs. You can input the same prompt with the same context, and get wildly different results every time. This is from a single prompt. The idea that you can get anything close to consistent results across a sequence of prompts is delusional.
You can try prompt "hacks" like STRONGLY EMPHASIZING correct behaviour (or threaten to murder kittens like in the old days), but the tool will eventually disregard an instruction, and then "apologize" profusely for it.
Comparing this to what a compiler does is absurd.[1]
Sometimes it feels like users of these tools are in entirely separate universes given the wildly different perspectives we have.
[1]: Spare me the examples of obscure compiler inconsistencies. These are leagues apart in every possible way.