On the eve of GPT-5’s first birthday, OpenAI and four rivals published Agent Plugins, an open standard that lets a single agent extension work across competing products. Agent Plugins replaces that with one package format. The second is Agent Skills, reusable sets of instructions. Who is behind itDespite the OpenAI billing, this is not an OpenAI product. Representatives from Amazon, Cursor’s maker Anysphere, GitHub, Microsoft, OpenAI, and Vercel then shaped the 1.0 specification.