Is qwen finetuned/RL'd on any agent harness? Or does it just work well enough off the bat with opencode?

If Qwen is finetuned for a hardness, it'll be Qwen Code. Qwen 27b works well enough in OpenCode though which is what I use. My one complaint is it likes to get cute with bash commands instead of OpenCode's built-in tools. I use a skill to steer that.