Summary
OpenAI announced GPT-5.2 on December 11, 2025, with Instant, Thinking, and Pro variants. The models became available in the API that day, while rollout in ChatGPT began with paid plans.
Editorial correction, October 26, 2026
The announcement establishes December 11, 2025, rather than February 1, 2026. The event is relocated to the 2025 directory while retaining its ID and public event URL. The announcement explicitly distinguishes Instant, Thinking, and Pro; the original summary's assertion that there were no separate thinking modes is withdrawn. The old source dates and original metadata are preserved in this revision record; the mutable platform guide is not assigned an invented publication date.
Revision record with the prior summary and metadata.
The original narrative below is preserved as published; use the revised summary and this note for the corrected account.
What Happened
GPT-5.2 arrived as a refinement of the GPT-5 line, with improved reasoning capabilities that rivaled the dedicated o-series models. Available through Azure AI Foundry and OpenAI's API, it used max_completion_tokens (spending reasoning tokens before visible output) rather than the traditional max_tokens parameter. The model did not support temperature=0, only default temperature of 1, reflecting its reasoning-native architecture.
Why It Matters
GPT-5.2 further blurred the line between "reasoning models" and "general models," suggesting the industry was converging on reasoning as a default capability rather than a specialized mode. The competitive pressure from DeepSeek's open-source reasoning models and Anthropic's hybrid thinking approach in Claude 3.7 made reasoning a table-stakes feature rather than a differentiator.
§ How to read the metadata
- Landmark
- Fundamentally alters the trajectory; 2–5 per year.
- Major
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- Notable
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- Contestation
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