We've revised the draft composer actions spec after implementing the first prototypes.

The main change is using postMessage for form-to-client communication, but we've also added a more detailed tech spec.

I'm very excited about these, but embedded forms open a new security/safety surface that clients need to approach carefully. 

I've heard from a lot of builders eager to create composer actions and appreciate your patience while we work out the right approach. If we get it right, it's a foundation for a whole class of new programmable social primitives.

https://warpcast.notion.site/Draft-Composer-Actions-7f2b8739ee8447cc8a6b518c234b1eeb