Extended Thinking Extended thinking gives the model a scratchpad before the final answer. Pay for reasoning tokens, get deeper answers. Use it surgically, not everywhere. When to Use - Complex reasoning: math, proofs, multi-step logic - Code generation where the model needs to plan before writing - Agent planning: deciding which of many tools to call and in what order - Debugging subtle issues: model can "think through" root causes - Writing where structure and coherence matter more than speed When NOT to Use - Simple classification, extraction, or formatting — pure overhead - Latency-sensiti…