As long as LLMs remains at the same skill level at coding, or better, there's 100% guarantee an MD (a glorified prompt) is gonna work as good as it’s “working” right now.
There is absolutely no guarantee llm1(MD) == llm2(MD), by design. With the current batch you need to explicitly constrain a number of parameters, far more than simply the prompt, to get identical output from the _same_ model, let alone another model that has varied training data and/or architecture.