I first found out about chat-sdk existence when I was upgrading my nanoclaw (its core feature is that it uses claude agent sdk under the hood as the harness) to v2 and they were migrating to chat-sdk as their base layer for supporting different channels.
It was pretty limited thought in terms of what I needed, so I had to through it away and build my own telegraf sdk based channel implementation for telegram, but that was a while ago, I assume they should have evolved a lot from the time I last touched it about 3 months ago.