With Opus 4.7, there's a 10 point improvement in the AA coding agent index when you swap out Claude Code for OpenCode: https://artificialanalysis.ai/agents/coding-agents#harness-c...

To put that in perspective, the difference between GPT-5.6 Sol Max and 5.6 Luna Max is 8 points. That's a lot of extra performance that you can get for free just by using the best harness.