Remember, Anthropic knows best for your workflow!
/s
This is why open harnesses and open models will always be superior, it's only a matter of time until someone decides that something you use isn't worth maintaining anymore. The reply from the Anthropic employee up above doesn't give me much confidence that Claude users will be able to continue using plan mode forever.
Codex and Claude Code are the best harnesses out there by a long shot. They work out of the box, require no real config, and just do the thing.
The flexibility and lightweight nature of open harnesses is mainly useful for open models. These models are considerably far behind the frontier and need a lot more steering. Complex harnesses confuse them. I use open harnesses for my OSS model rig because the model needs it.