OpenCode shares a similar primary/subagent system to Claude Code, and is also the base for many CLI tools (e.g., Kimi CLI)

For example, providers like Synthetic seem to work really well under OpenCode, and does not require any odd workarounds, if any, to be used in Claude Code.

What's more than likely is that Claude Code, while popular, is not exactly in the best position due to recent controversies surrounding provider lockdown and the way the application itself is programmed, all while OpenCode is being actively updated, and only keeps growing more and more according to its repo activity.