Subagents in OpenCode suck. They're blank-slate black boxes that block execution.

OMP spawns agents asynchronously, letting the main agent check on them periodically and even chat back and forth with the subagents to coordinate dynamically instead of losing control after initial prompt (it's also very amusing, like watching Sims play office).

OMP also has /tan tangential prompt which spawns subagents that reuse entire conversation prefix (cached), so you don't waste tokens on sending them a recap of the situation and them re-discovering the codebase themselves. OpenCode kinda does it with fork + switch of sessions, but a command inside one session is quicker.

I had a really bad experience using OpenCode with Ox Alpha (when it was a stealth model on openrouter), with the model making countless mistakes. Then I tried omp with the same model and it was a million times better. I haven't looked back.

omp is feature rich, and it's very actively developed. I don't have the time or interest to pick and choose among the thousands of pi extensions, so the fact that omp already has a lot of useful things built it is a good match for me.

A major aspect is that it automated out-of-the-box a pattern I naturally would do of writing a spec just before the context window would fill and then compacting and continuing.

Now I just write a prompt and OMP just hammers away at it. There might very well be some OpenCode plugin for this but it just works out of the box with OMP.