I highly recommend just getting out of Anthropic's (or anyone's) vendor lock-in. Use opencode or pi. You can still use your subscription pricing using a proxy. I switched to opencode and haven't looked back.

Antigravity is probably the best of the bunch I've tried. I'd say it's pretty comparable to Claude Code (I use both daily).

I resisted at first but now I main antigravity for work. All the software (web, react-native app, client cms platform, postgres backed, multiple ETL systems, a few chat/websocket backends) for my company is loaded into a single project. I spend time writing prompts and forming plans back and forth with the agents then I click GO. Over the past year we've gone from it taking minutes and needing a reasonable amount of back and forth and fixing, to it taking 10-20 seconds and outputting near perfect work within my system accross app/service boundaries.

Pi [1] is amazing. Since using it I've felt no need to switch harnesses anymore.

Or choose Oh My PI [2] for batteries included

[1] https://github.com/earendil-works/pi [2] https://github.com/can1357/oh-my-pi

Crush is great: https://github.com/charmbracelet/crush

If you're on their subscription plan - agy cli or antigravity ui is the only choice i think.

Anyway - if you're a dev - you would be writing your own agentic env right ? that's the best way forward. I wont tell you more than this . but if you're not - you are losing out .

You can use any model with Claude Code. Most chinese one have a Anthropic compatible endpoint and for Google and OpenAI's models you can get a compatible endpoint with a proxy like Bifrost. No need to change your harness.

The vscode chat is great. Not sure if it's also called copilot, but you can plug in any models there and they get sandboxed, tools and link to your code. Great stuff.

Antigravity has been also rapidly improving lately, and your can also use any of the open coding harnesses. But I mostly meant “harness” as in your workflow/loop setup.