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.

OpenAI subsequently added GPT-5.4 mini and nano, the restricted GPT-5.4-Cyber, GPT-5.5 for more autonomous work, GPT-5.5 Instant, and July’s GPT-5.6 Sol, Terra, and Luna models.

From the Codex Mac app to a new ChatGPT

The software around those models transformed too. OpenAI launched a dedicated Codex Mac app in February as a hub for running multiple coding agents, reviewing changes, and scheduling work.

In July, Codex effectively became the new ChatGPT desktop app, combining Chat, Work, and Codex while the previous native client was renamed ChatGPT Classic.

For me, Codex has changed how I work with ChatGPT the most. I’m able to offload a lot more work that doesn’t require critical thinking and even build tools on my Mac that I couldn’t put together otherwise.

OpenAI introduces Agent Plugins

Next, OpenAI is introducing Agent Plugins that offer a portable package format for bundling skills and MCP servers.

Agent Plugins is an open, vendor-neutral standard for packaging reusable components into portable plugins. Its version 1.0.0 specification defines a shared format for Agent Skills and MCP servers that compatible clients can discover and load consistently.

Per the Agent Plugins site, the technology is “openly licensed and developed in public.” The vendor-neutral project’s steering committee includes Amazon, Cursor, Microsoft, OpenAI, and Vercel.

When is GPT-6 coming?

OpenAI has not announced GPT-6. The clearest clue is Astra, an unreleased model family. OpenAI recently said an internal version advanced 10 longstanding math and computer-science problems, but the company has not called Astra GPT-6.

Release timing may no longer be OpenAI’s decision alone. GPT-5.6’s public rollout was briefly held back for US government security review. Astra could be close without being imminent. It could also arrive under yet another GPT-5 name.

However it goes, tomorrow marks one year with GPT-5, and for me, the arrival of Codex as an agentic tool has changed my use the most, year-over-year.

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