We have an OCR job running with a lot of domain specific knowledge. After testing different models we have clear results that some prompts are more effective with some models, and also some general observations (eg, some prompts performed badly across all models).

Sample size was 1000 jobs per prompt/model. We run them once per month to detect regression as well.

OK, so a while back I set up a workflow to do language tagging. There were 6-8 stages in the pipeline where it would go out to an LLM and come back. Each one has its own prompt that has to be tweaked to get it to give decent results. I was only doing it for a smallish batch (150 short conversations) and only for private use; but I definitely wouldn't switch models without doing another informal round of quality assessment and prompt tweaking. If this were something I was using in production there would be a whole different level of testing and quality required before switching to a different model.

Enterprises moving slow, or preferring to remain on old technology that they already know how to work...is received wisdom in hn-adjacent computing, a truism known and reported for more than 3 decades (5 decades since the Mythical Man-Month).

Sounds like someone who's responsible, on the hook, for a bunch of processes, repeatable processes (as much as LLM driven processes will be), operating at scale.

Just in the open, tools like open-webui bolts on evals so you can compare: how different models, including new ones, perform on the tasks that you in particular care about.

Indeed LLM model providers mainly don't release models that do worse on benchmarks—running evals is the same kind of testing, but outside the corporate boundary, pre-release feedback loop, and public evaluation.

https://chatgpt.com/share/69aa1972-ae84-800a-9cb1-de5d5fd7a4...

Tell us more about how you've never actually used these APIs in production

Like, bro, do you think 5.x is a drop in replacement for 4.1? No it obviously wasn’t, since it had reasoning effort and verbosity and no more temperature setting, etc.

There’s no way you can switch model versions without testing and tweaking prompts, even the outputs usually look different. You pin it on a very specific version like gpt-5.2-20250308 in prod.