GPT-5.5 prompting guide

Simon Willison Blog
Generative AI

GPT-5.5 prompting guide Now that GPT-5.5 is available in the API, OpenAI have released a wealth of useful tips on how best to prompt the new model. Here's a neat trick they recommend for applications that might spend considerable time thinking before returning a user-visible response: Before any tool calls for a multi-step task, send a short user-visible update that acknowledges the request and states the first step. Keep it to one or two sentences. I've already noticed their Codex app doing this, and it does make longer running tasks feel less like the model has crashed.