Harness engineering is a moat. There’s user loyalty and reliance on the chassis that Claude is on, for example, just like there’s more market share by MacOS+WindowsOS over Linux Open Source.

I regularly switch between codex and Claude in the same sessions. I’d throw in other models if I could.

Data governance and enterprise sales is a moat. The harnesses aren’t.

I thought so too.

But 1) people use other models with that same harness. 2) I moved on from Claude Code and all the features I cared for up and running in less than a couple days. Without even looking for available plugins or extensions.