We trained GPT‑5 on real-world coding tasks in collaboration with early testers across startups and enterprises. Cursor says GPT‑5 is “the smartest model [they’ve] used” and “remarkably intelligent, easy to steer, and even has a personality [they] haven’t seen in other models.” Windsurf shared GPT‑5 is SOTA on their evals and “has half the tool calling error rate over other frontier models.” Vercel says “it’s the best frontend AI model, hitting top performance across both the aesthetic sense and the code quality, putting it in a category of its own.”

GPT‑5 also excels at long-running agentic tasks—achieving SOTA results on τ2-bench telecom (96.7%), a tool-calling benchmark released just 2 months ago. GPT‑5’s improved tool intelligence lets it reliably chain together dozens of tool calls—both in sequence and in parallel—without losing its way, making it far better at executing complex, real-world tasks end to end. It also follows tool instructions more precisely, is better at handling tool errors, and excels at long-context content retrieval. Manus says GPT‑5 “achieved the best performance [they’ve] ever seen from a single model on [their] internal benchmarks.” Notion says “[the model’s] rapid responses, especially in low reasoning mode, make GPT‑5 an ideal model when you need complex tasks solved in one shot.” Inditex shared “what truly sets [GPT‑5] apart is the depth of its reasoning: nuanced, multi-layered answers that reflect real subject-matter understanding.”

We’re introducing new features in our API to give developers more control over model responses. GPT‑5 supports a new verbosity parameter (values: low, medium, high) to help control whether answers are short and to the point or long and comprehensive. GPT‑5’s reasoning_effort parameter can now take a minimal value to get answers back faster, without extensive reasoning first. We’ve also added a new tool type—custom tools—to let GPT‑5 call tools with plaintext instead of JSON. Custom tools support constraining by developer-supplied context-free grammars.

We’re releasing GPT‑5 in three sizes in the API—gpt-5, gpt-5-mini, and gpt-5-nano—to give developers more flexibility to trade off performance, cost, and latency. While GPT‑5 in ChatGPT is a system of reasoning, non-reasoning, and router models, GPT‑5 in the API platform is the reasoning model that powers maximum performance in ChatGPT. Notably, GPT‑5 with minimal reasoning is a different model than the non-reasoning model in ChatGPT, and is better tuned for developers. The non-reasoning model used in ChatGPT is available as gpt-5-chat-latest.