
The Stack
AI 101 — What are reasoning tokens?
Reasoning tokens are the hidden text a model generates to think through a problem before giving you its answer — invisible, billed to your account, and the reason modern AI can suddenly solve hard questions. When you ask a regular chatbot a question, it reads your words and starts writing a reply immediately. When you ask a reasoning model — OpenAI's o3, DeepSeek's R1, or Google's Gemini with "thinking" enabled — something different happens first: the model spends time generating an internal mo










