OpenAI releases GPT-5.5 prompting guide emphasizing outcome-oriented instructions over process-heavy prompts

OpenAI published guidance on prompting GPT-5.5, recommending that prompts define the target outcome and constraints while allowing the model to choose its solution path, in contrast to older prompts that over-specified procedural steps.

GPT-5.5's default style is efficient and task-oriented; for conversational products, users should define both personality (tone, warmth, directness) and collaboration style (when to ask questions, how proactive to be) separately, keeping both blocks short.

For streaming applications where users notice delays before visible responses, prompts should instruct the model to emit a short preamble acknowledging the request and stating the first step before making tool calls or running multi-step agent workflows.