[tifa2up]

For large context (up to 100K tokens in some cases). We found that GPT-5: a) has worse instruction following; doesn't follow the system prompt b) produces very long answers which resulted in a bad ux c) has 125K context window so extreme cases resulted in an error

[internet_points]

Interesting. https://www.robert-glaser.de/prompts-as-programs-in-gpt-5/ claims GPT-5 has amazing!1!! instruction following. Is your use-case very different, or is this yet another case of "developer A got lucky, developer B tested more things"?

[tifa2up]

Think it varies by use case. It didn't do well with long context

[Shank]

ChatGPT when using 5 or 5-Thinking doesn’t even follow my “custom instructions” on the web version. It’s a serious downgrade compared to the prior generation of models.

[cj]

It does “follow” custom instructions. But more as a suggestion rather than a requirement (compared to other models)

[Xmd5a]

Ah, 100k/125K this is what poses problems I believe. GPT-5 scores should go up should you process contexts that are 10 times shorter.