I tried Happy Coder for a bit. It seemed exactly what I was missing but about 1/2 the time session notifications weren't coming through and the developers of the tool seem busy pushing it off in other directions rather than in making the core functionality bullet-proof so I gave up on it. Unfortunate. Hopefully something else pops up or Anthropic bakes it into their own tooling.
It would be great to be able to check in on Claude on a walk or something to make sure it hasn't gone off the rails or send it a quick "LGTM" to keep moving down a large PLAN.md file without being tethered to a keyboard and monitor. I can SSH from my phone but the CLI ergonomics are ... not great with an on screen keyboard, when all it really needs is just needs a simple threaded chat UI.
I've seen a couple Github projects and "Happy Coder" on a Show HN which I haven't got around to setting up yet which seem in the ballpark of what I want, but a first party integration would always be cool.