AI Anthropic and OpenAI cosign UI app layer for MCP SEP-1865 seeks to formalise MCP-UI as an extension before UI SDKs proliferate, starting with HTML. Phillip de Wet Nov 24, 2025 - 2 min read Photo by Candice Seplow on Unsplash Get the full story: Subscribe for free Join peers managing over $100 billion in annual IT spend and subscribe to unlock full access to The Stack’s analysis and events. Subscribe now Already a member? Sign in