GPT-5.6 Prompting Guide: Shorter and More Proactive

cedric_chee · x · 2026-07-10

A developer shared key takeaways from the official GPT-5.6 prompting guide. It recommends using shorter prompts, as the model behaves more proactively and persistently. Additionally, GPT-5.6 is more sensitive to instructions like "be concise" compared to GPT-5.5, and supports both Standard and Pro reasoning modes in the Responses API.

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