> How different the output is each time you generate something from an LLM is a property called 'prompt adherence'. It's not really a big deal in coding LLMs, (...)

I strongly disagree. Nowadays most LLMs support updating context with chat history. This means the output of a LLM will be influenced by what prompts you have been feeding it. You can see glaring changes in what a coding agent does based on what topics you researched.

To take the example a step further, some LLMs even update their system prompts to include context such as where you are in the world at that precise moment and the time of the year. Once I had ChatGPT generate a complete example project based around an event that was taking place at a city I happened to be cruising through at that moment.