Agent Use Interface (AUI) – let users bring their own AI agent

Description

As I started building AI integrations, I came to realize that for many projects, the the best agentic experience is one that simply enables the user's personal agent to take actions within your app. The existing options like MCP or A2A are quite involved and for simple apps that are already URL parameter driven, those options seem like overkill. This led me to prototype the Agent Use Interface (AUI) spec. The idea is simple: a lightweight, open spec that makes any app "agent-navi