Help deciding on best harness for developing a custom agent orchastrator?

Been developing a custom agent orchestration layer with opencode as the harnes. It has been successful so far in terms on being manage multiple concurrent sessions. However, I am wondering if I am using the best harness given that opencode isn't meant to be a hackable, i.e. Less flexible compared to something like pi.

I've developed an interface that allows me to easily switch between different harnesses. i.e. Without having to re-write the orchestration layer, and am considering swapping out opencode for pi. The reasoning is obvious, pi is meant to be a hackable harness, so its likely to be a better fit for building a custom multi-agent system. Opencode does support a headless mode which has helped a lot. But it seems heavy on resources, and recently has seemed very buggy. Less features might be a better approach towards the stability that I need.

Before I make the dive, has anyone else already tried integrating pi into a multi-agent system? Did you find pi a better fit for the worker layer compared to something like opencode? What problems did you run into?

Thanks for your help.