Great question! You can configure multiple coasts, so you could have a coast running with isolated dbs/state and also a shared version (you can either share the volume amongst the running coasts or move your db to run host-side as a singleton). So its sort of left to the orchestration layer: you put rules in your md file about when to use each. There's trade-offs to each scenario. I've been using isolated dbs for integration tests, but then for UI things I end up going with shared services.
>Re: For example, if two agents are both making schema changes to a shared database service
Obviously things can still go wrong here in the shared scenario, but it's worked fine for us and I haven't hit anything so far. It's just like having developers introducing schema changes across feature branches.
>Also, the per-service strategy config (none/hot/restart/rebuild) seems like the right abstraction. Most of the overhead in switching worktrees comes from unnecessary full restarts of services that don't actually care about the code change.
Totally, at first switching worktrees for our 1m+ loc repo was like 2 minutes. Then we introduced the hot/none strategies and got it down to like 8s. This is by far one of the best features we have.