Stop adding 'think step by step' to reasoning models — explicit CoT now hurts

The AI Corner·high signal

The 2026 context-engineering guidance is that explicit chain-of-thought instructions like 'think step by step,' which helped older models, are now redundant or actively harmful on reasoning models that already do internal CoT. Strip these directives from prompts aimed at reasoning-tier models and reinvest the prompt budget in context: what the model can see, retrieve, and remember at the moment of action. Re-audit prompt templates carried over from 2024–2025, since techniques that worked then can now degrade results.