FrontierThe story, in brief
GPT-5.4 Thinking System Card
GPT-5.4 arrives with a 'thinking' layer. OpenAI just changed how reasoning models work.
The KeyNews take
Why it matters
OpenAI's new reasoning architecture introduces explicit 'thinking' tokens that let models work through problems step-by-step before answering. This represents a fundamental shift in how frontier models approach complex reasoning tasks and likely signals an arms race in reasoning-chain transparency.
The key facts
5 to knowGPT-5.4 introduces explicit 'thinking system' capability
Reasoning approach uses intermediate token generation before final output
Official system card published—indicates production-ready feature
Published March 5, 2026
Direct competition with Claude's chain-of-thought and reasoning models
Go to the source
OpenAI Blogopenai.com