OpenAI’s GPT-5 turns one tomorrow, and the company is marking the week by looking beyond individual models. Today, OpenAI introduced Agent Plugins, an open standard meant to let reusable AI-agent extensions work across compatible products.
GPT-5’s first year
GPT-5 launched August 7, 2025, replacing GPT-4o and several reasoning models as ChatGPT’s default. Its defining feature was automatic routing: ChatGPT could answer quickly or invoke deeper reasoning depending on the request. OpenAI also claimed fewer factual errors than GPT-4o.
Apple adopted the model with iOS 26, iPadOS 26, and macOS Tahoe 26. ChatGPT requests passed through Apple Intelligence, including Siri handoffs, Writing Tools, and visual intelligence, switched from GPT-4o to GPT-5.
GPT-5.1 promised warmer, more natural answers in November. December’s “code red” GPT-5.2 accelerated professional work in response to Gemini. GPT-5.3 Instant targeted ChatGPT’s “cringe” tone, followed two days later by GPT-5.4 Thinking with a million-token context window and built-in computer use.
