The harness if anything matters more with those other models because of how much dumber they are... You can compensate for some of the stupidity (but by no mean

The harness if anything matters more with those other models because of how much dumber they are... You can compensate for some of the stupidity (but by no means all) with harnesses that tries to compensate in ways that e.g. Claude Code does not because it isn't necessary to do so for Anthropics own models.