Not proprietary and not a wrapper. Chat SDK served as inspiration, of course, but I think it misses a few hard parts of bringing agents to chat interfaces:

- Generative UI in these surfaces needs to be durable. If your agent composes a Block Kit or Adaptive Cards interface with interactivity, you have to be ready to handle that interactivity weeks later. We handle this with our JSX renderer.

- Chat interfaces are inherently multiplayer. The worst thing you can do is have your agent act like a bot: posting all of the time, creating noise, and offering no customization. I think Claude Tag nailed the user experience here, and now we want to empower developers to create agents with a similar UX via open source.

- Truly agent-and-surface agnostic. We're fully powered by AG-UI (ag-ui.com), so you can bring any agent into Slack and then take that same agent to web or mobile all over the same protocol.

Fair on AG-UI, that part is a real difference. But the Chat SDK point is a bit overstated: vercel/chat also has a JSX card system that renders to Block Kit and Adaptive Cards, with button and action handlers and pluggable state backends.

> Chat interfaces are inherently multiplayer.

Both chat and channel sdks support subscribing to threads and can control messages that arrive concurrently. In that regard it feels like this depends more on the logic of the app itself rather than gets defined by the framework/dependency it uses.