OpenAI Unveils GPT-5.5 'Spud': Smarter ChatGPT with Agentic Reasoning

OpenAI has officially launched GPT-5.5, codenamed 'Spud,' on April 23, 2026. This release, alongside GPT-5.5 Pro, introduces advanced agentic reasoning to ChatGPT, enabling the AI to autonomously handle complex, multi-step professional tasks. GPT-5.5 scores 82.7% on Terminal-Bench 2.0 and 51.7% on FrontierMath 1-3 benchmarks. The model is now the default for all ChatGPT Plus, Pro, Business, and Enterprise subscribers, offering an immediate boost in AI capabilities. It is also available through Microsoft Foundry for enterprise integration.