GPT-5.5 Prompting Guide

OpenAI released a prompting guide for GPT-5.5, presenting writing methods and upgrade directions tailored to the new model.

In particular, for cases where responses take time, such as multi-step tasks, it recommended sending a short user-visible update before tool calls. One or two sentences confirming the request and stating the first step are enough, and this approach reduces the problem of long tasks appearing to have stalled.

OpenAI also explained a flow for upgrading existing code by running the openai-docs migrate this project to gpt-5.5 command in Codex. The upgrade guide followed in this process includes methods for lightly rewriting prompts to fit the model.

The most important message is not to treat GPT-5.5 as a simple replacement for gpt-5.2 or gpt-5.4.

• Rather than porting the existing prompt stack as is, it recommended starting from a new baseline.
• It advised building from the smallest prompt that maintains the product contract.
• Afterward, it guided readjusting reasoning effort, verbosity, tool descriptions, and output format using representative examples.

In other words, the message is that for GPT-5.5, an approach of retuning from scratch to fit the new model's characteristics is more effective than simply layering existing prompts on top.