My current fave harness. I've been using it to great effect, since it is self-extensible, and added support for it to https://github.com/rcarmo/vibes because it is so much faster than ACP.

Pi has made all the right design choices. Shout out to Mario (and Armin the OG stan) — great taste shows itself.

there is also pz a drop-in replacement for pi rewritten in Zig. 1.7MB static binary, 3ms startup, 1.4MB RAM idle. Find more at:

https://github.com/elyase/awesome-personal-ai-assistants?tab...

Preconfigured PI: https://github.com/can1357/oh-my-pi

Hugging Face now provides instructions for using local models in Pi:

https://x.com/victormustar/status/2026380984866710002

I’m working with a friend to build an ui around Pi to make it more user friendly for people who prefer to work with a gui (ala conductor). You can check out the repo: https://github.com/philipp-spiess/modern

Note there is a fork oh-my-pi: https://github.com/can1357/oh-my-pi of https://blog.can.ac/2026/02/12/the-harness-problem/ fame. I use it as a daily driver but I also love pi.

Pi ships with powerful defaults but skips features like sub-agents and plan mode

Does anyone have an idea as to why this would be a feature? don't you want to have a discussion with your agent to iron out the details before moving onto the implementation (build) phase?

In any case, looks cool :)

EDIT 1: Formatting EDIT 2: Thanks everyone for your input. I was not aware of the extensibility model that pi had in mind or that you can also iterate your plan on a PLAN.md file. Very interesting approach. I'll have a look and give it a go.

Is that an official term "coding harness"

Wondering if you wanted a similar interface (though a GUI not just CLI) where it's not for coding what would you call that?

Same idea cycle through models, ask question, drag-drop images, etc...

I've been using Pi day to day recently for simple, smaller tasks. It's a great harness for use with smaller parameter size models given the system prompt is quite a bit shorter vs Claude or Codex (and it uses a nice small set of tools by default).

Has anyone used an open coding agent in headless mode? I have a system cobbled together with exceptions going to a centralized system where I can then have each one pulled out and `claude -p`'d but I'd rather just integrate an open coding agent into the loop because it's less janky and then I'll have it try to fix the problem and propose a PR for me to review. If anyone else has used pi.dev or opencode or aider in this mode (completely non-interactive until the PR) I'd be curious to hear.

EDIT: Thank you to both responders. I'll just try the two options out then.

The way you’re able to extend the harness through extension/hook architecture is really cool.

Eg some form of comprehensive planning/spec workflow is best modeled as an extension vs natively built in. And the extension still ends up feeling “native” in use

I’ve been testing it for a few days on pretty much clean install (no customizations/extensions) and it’s ok. Not sure if I like it yet.

But I can't use my Codex plan with it, right? I have to use an API key?

Anyone managed to run pi in a completely sandboxed environment? It can only access the cwd and subdirectories

The backing to OpenClaw/MoltBot whatever they're calling themselves. Why is it insecure, well, Pi tells you >No permission popups.

Anyway, even if you give your agent permission, there's no secure way to know whether what they're asking to is what they'll actually do, etc.

Just how expensive was that domain?