There's a very interesting benchmark comparison below of Opus 4.7 run under three different harnesses : OpenCode, Cursor and Claude Code where it's not very close at all and Opus's native harness, Claude Code, performs worst of all three.

The pass@1 scores are 50/45/40 for OpenCode/Cursor/Claude Code respectively.

https://artificialanalysis.ai/agents/coding-agents#harness-c...

I've seen other benchmarks where Pi also outperforms Claude Code both in model performance and in much reduced token usage.