Reasoning Model
A class of LLMs (OpenAI o-series, Claude with extended thinking, DeepSeek-R1) trained to spend significant inference-time compute on internal reasoning before producing the final answer. Substantially better on math, coding, and multi-step problems at the cost of higher latency and token consumption.
Related terms
- Chain-of-Thought (CoT)
A prompting or training pattern where the model produces intermediate reasoning steps before its final answer, typically improving accuracy on multi-step tasks. Modern reasoning models (o1, o3, Claude with extended thinking) internalize CoT during training.
- Context Window
The maximum span of tokens an LLM can consider in a single forward pass. Frontier models in 2026 support 1M-2M token contexts, but effective context (measurable retrieval accuracy across the window) usually lags nominal capacity.
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Where this fits
Reasoning Model is part of the AI Fundamentals vocabulary used in the Generative AI Maturity Framework. See the full glossary for the complete set of 149 defined terms, or take the free maturity assessment to see where your organisation stands.