Stop writing 'let's think step by step' on frontier reasoning models — it's now counterproductive

Karo Zieminski·high signal

On 2026 reasoning models (Opus, o3, Gemini, R1) the chain-of-thought happens in dedicated hidden tokens, so the old 'think step by step' incantation either does nothing or actively degrades output by redirecting deliberation that already exists. Instead of triggering reasoning, your prompt should direct it: state the decision criteria, constraints, and what 'good' looks like, and let the model's internal reasoning do the rest. This is a clean inversion of a habit most senior practitioners still carry over from the GPT-3.5 era.