What’s the best local AI harness for coding + general use?

So what’s actually the best local AI harness rn?

I’ve read a TON about this already and somehow ended up more confused than when I started so I figured screw it, let the community decide.

Right now I mainly run Qwen 3.6 35B-A3B and Qwen 3.8 27B, with Ornith 1.5 9B sometimes for lighter stuff.

The models themselves are honestly pretty damn good, but the harness situation is where I’m completely lostw and bad harness messes it all

Like Pi, Hermes TUI, OpenCode, etc. what do you actually use, and what tools/MCPs/external stuff do you pair with it?

I’ve mostly used Codex and Claude Code until now, but they don’t always play nicely with local/open models. A lot of the time it feels like the model is capable of doing something, but the harness/tool calling/system prompt setup just gets in the way.

I’m looking for something that works well for both coding AND general-purpose agent stuff, not just “edit this file and run tests.”

So what’s your setup?

Which harness?
Which local model(s)?
What inference backend? (i use llama cpp mainly)
Any MCPs/tools/extensions you consider essential?
And most importantly: why that harness over Pi/OpenCode/Hermes/etc.?

Would especially love to hear from people actually running 27B–35B-ish Qwen models locally, rather than cloud-model recommendations.

I’m genuinely curious what people have settled on because there seem to be like 50+ options noww
Also
WHATS THE BIGGEST PROBLEM YOU GUYS FACE?