I've recently been using Amp a bit more, given you can now use your Claude subscription with it. In a similar vein to Adding Pushover notifications to Claude Code, I've been wanting to get notified when a given session is waiting for input.
Although I wrote a very small CLI, claude-hook which I'd wondered about extending for Amp's usage, I found that Amp's Typescript-based plugins are much more powerful, and avoid me needing to create a wrapper CLI, even though I'd hoped to keep the codebase the same across different agent tools.
(While, at the same time, not getting as much contextual information out of the Thread, which is a bit annoying)
I partially wrote, and then had Amp + Claude Opus 5.5 fix up, this small Amp Plugin to notify me on agent.end.
This then shows me i.e.