OpenAI: o1

Implements large-scale reinforcement learning-trained reasoning that allocates variable computation time before generating responses, using an internal chain-of-thought process that explores multiple solution paths and validates reasoning steps. The model learns to spend more computational budget on harder problems through RLHF training, enabling deeper exploration of complex logical, mathematical, and algorithmic problems before committing to an answer.

Leverages reinforcement-learning-trained reasoning to automatically decompose complex problems spanning multiple domains (mathematics, physics, coding, logic) into sub-problems, solve each with domain-specific reasoning patterns, and synthesize solutions. The model learns through RLHF which decomposition strategies lead to correct answers, enabling it to handle problems that require reasoning across traditionally separate domains.

Generates code while internally reasoning about correctness, edge cases, and potential bugs through extended chain-of-thought before producing output. The model explores multiple implementation approaches and validates logic against problem constraints during the reasoning phase, producing code with higher correctness rates on complex algorithmic problems. Integration via OpenAI API accepts code problem descriptions and returns verified implementations.

Applies extended reasoning to mathematical problem-solving, including symbolic manipulation, proof construction, and numerical validation. The model learns through RLHF to apply appropriate mathematical techniques (induction, contradiction, calculus, linear algebra) and verify intermediate steps before producing final answers. Integrates via OpenAI API to accept mathematical problem statements and return step-by-step solutions with reasoning.

Processes extended text contexts (up to model's maximum token limit) while applying reasoning to understand relationships, contradictions, and implications across the full document. The model uses learned reasoning patterns to identify relevant sections, synthesize information across distant parts of the context, and reason about document structure. Integrates via OpenAI API to accept long documents and reasoning queries.

During extended reasoning, the model explores potential edge cases, adversarial inputs, and failure modes before responding. The RLHF training teaches the model to consider 'what could go wrong' and validate solutions against edge cases, producing more robust answers. This is particularly effective for security-sensitive code, mathematical proofs, and system design where edge cases are critical.

Exposes o1 reasoning capabilities through OpenAI's REST API with support for streaming reasoning tokens (in preview/beta), allowing developers to integrate extended reasoning into applications. The API accepts standard chat completion requests and returns responses with internal reasoning tokens optionally exposed for transparency. Supports both synchronous and asynchronous inference patterns with configurable reasoning budgets (in some variants).

Maintains reasoning context across multiple conversation turns, allowing the model to build on previous reasoning and avoid re-deriving conclusions. Each turn applies extended reasoning to new queries while leveraging learned patterns from prior turns. The API maintains conversation history and applies reasoning to understand how new queries relate to previous context.