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OpenAI releases o1-preview

OpenAI released an early o1 reasoning model for use in ChatGPT and selected API access.

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The preview made inference-time reasoning a visible product feature. Its release did not establish superiority on every task.

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OpenAI releases o1-preview - source record

openai.com

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Published: Publication date not provided
Source checked: 9/21/2026

Revision 1 / Reviewed 9/21/2026

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