claude --worktree is great for isolating a single session, but you're still juggling terminal tabs manually — starting each one, switching between them to check progress, reviewing diffs by hand.

ChatML is basically the management layer on top of that. You get a dashboard where you can run 3-5 agents at once, each in its own worktree, and see what they're all doing without tab-switching. It also handles the worktree lifecycle for you (creation, branching, cleanup), has a built-in diff viewer with code review, tracks cost per session, and lets you open PRs directly.

Closest analogy: running containers manually vs. having Compose manage them. Same underlying primitive, but the orchestration matters once you're doing it regularly.

Yes. In November/December timeframe when Opus 4.5 came out, I realized I was trusting it to write the code. I was doing light reviews. I had tried a few MacOS products that does this orchestration, but I was needing more and they weren't answering my emails.

It was then I realized I had to build ChatML. The first commit was on January 17, so it took about 45 days to get this out, so people can use...

One weekend I closed 120 PR's with on average 10-15 Worktree sessions at any given time. The hardest was to learn how to context-switch in your mind. I built some MacOS Notifications and audible alerts to catch my attention when new plan was proposed in a session, an agent asking questions, etc....

It worked really well for ChatML, since I developed ChatML with ChatML. 750+ Pull Request done 100% by AI.

That's awesome. Let me know if you have any questions setting it up.

Yes. Each session get it's up to 5 Terminal sessions. So if I want to test a particular session I was just spinning servers for that session. I had to prepare the code in development to attempt to use multiple ports in case we had another session running.... But I had no problems.... I am writing a feature that you can configure init and tear tasks, so you can do things like "npm install", "docker-compose up", etc.... I had it working, but needed more test, so I commented out from the initial release. I will be adding that shortly after some more testing.

Thanks. Let me know what you think.