GPT-5.5 prompting guide
Summary
OpenAI has released a prompting guide for GPT-5.5 (a new version of their language model), which includes tips for improving user experience and migrating existing code. One key recommendation is to send brief status updates to users before starting multi-step tasks, so long-running operations don't appear frozen. The guide also advises treating GPT-5.5 as a new model family rather than a drop-in replacement, suggesting developers start fresh with minimal prompts (instructions given to the AI) and gradually tune them for the new model instead of reusing old ones.
Solution / Mitigation
OpenAI recommends running the command "$openai-docs migrate this project to gpt-5.5" in Codex to upgrade existing code. For manual migration, OpenAI advises: begin with a fresh baseline instead of carrying over every instruction from older prompts, start with the smallest prompt that preserves the product contract, then tune reasoning effort, verbosity, tool descriptions, and output format against representative examples.
Classification
Affected Vendors
Related Issues
Original source: https://simonwillison.net/2026/Apr/25/gpt-5-5-prompting-guide/#atom-everything
First tracked: April 25, 2026 at 02:00 AM
Classified by LLM (prompt v3) · confidence: 95%