GPT-5.5 is the first model in ChatGPT to which I’ve been able to just describe my desired response style, have it understand and remember it, and then actually respond in that exact way. I want it to write like a normal person, to default to narrative with some personality, to use minimal staccato-style lists and headers and bolding, but to feel free to use formatting when it will improve readability and scannability or help it emphasize key points. But sparingly! I previously crafted custom instructions for this with painstaking experimentation and it still didn’t work great because the models always went too far one way or another. Either too much formatting or no formatting at all, the latter of which resulted in weird things like bulleted lists that just didn’t have any bullets. Yesterday I spent time just describing to ChatGPT my desired response style, and even my background (magazine journalism, long ago, which influences my taste in writing). It understood, recorded a memory, and now writes as desired. I’ll continue to monitor and probably tweak, but right now, this is working well. (PS: One reason I did this was because I had to override outdated formatting guidance it still remembered from my instructions for older models. The new memory of how I want it to write does seem to be counteracting that older memory until it fades away, thankfully.)