OpenAI rolls out GPT-5 and GPT-5 Thinking to >1B users worldwide; -mini and -nano help claim Pareto Frontier

**OpenAI** launched **GPT-5**, a unified system featuring a fast main model and a deeper thinking model with a real-time router, supporting up to **400K context length** and aggressive pricing that reclaims the Pareto Frontier of Intelligence. The rollout includes variants like **gpt-5-mini** and **gpt-5-nano** with significant cost reductions, and integrations with products such as **ChatGPT**, **Cursor AI**, **JetBrains AI Assistant**, **Microsoft Copilot**, **Notion AI**, and **Perplexity AI**. Benchmarks show GPT-5 performing strongly in coding and long-context reasoning, roughly matching **Claude 4.1 Sonnet/Opus** on SWE-bench Verified. The launch was accompanied by a GPT-5 prompting cookbook and notable community discussions on pricing and performance.