Ask PH: Worktrees or isolated sandboxes for multi-agent AI workloads?

Git worktrees have become the default recommendation for running parallel AI coding agents (Claude Code, Codex, Cursor, etc.), and I get the appeal — they're just directories, zero orchestration, instant setup. I've seen people running 5 worktrees in a tmux grid with a separate Claude instance in each pane and it looks great on paper.

But I keep running into the same wall: worktrees isolate code, not the environment. Port 3000/5432/8080 still gets fought over. Two agents installing conflicting deps stomp on each other. Secrets in the host env leak into every subprocess any agent spawns.

Containers fix all of this cleanly, but now you're managing image lifecycles, cleanup policies, and orchestration — which is a lot of overhead for what might be a solo dev workflow. Curious what people have actually found:

1/ At what scale or workload type did worktrees start visibly breaking down for you?

2/ Has anyone found a middle ground that doesn't require full container orchestration?

3/ For those who moved to proper sandboxes: was the management overhead actually as painful day-to-day as it sounds upfront?