The new pricing model where I got banned from using Opus entirely and half a day of work (with weaker models) consumed the 10$ plan was.
I'm now using a Claude Max subscription and I can get close to the daily limits but I'm fairly happy with the overall plan consumption.
ACP is just a standard that bridges harnesses easily into IDEs, Text Editors, or whatever consumes it (I wrote a TUI that consumes them)
The registry for all the agents (tool harnesses) is here https://github.com/agentclientprotocol/registry if you ever are curious to what Zed or IntelliJ are really hooking into