Coasts
Containerized Hosts
Horizontal scaling for localhost.
Free, OSS, works with any harness, no AI upsells.
// the problem
Worktrees isolate code, not runtimes.
Your agents work in parallel, but your machine doesn't. Every worktree still runs on the same local environment — causing potential migration conflicts, port collisions, and competition for shared resources. So you validate sequentially, spin up cloud resources, or buy another laptop — while the bulk of your hardware sits idle.
Coasts are the local-first, free and open source solution to spawning parallel runtimes for your agents. A coast is a full runtime — its own ports, its own network, its own services. Run each stack in full isolation, or choose which resources to share across your coasts. Coasts work with any agentic coding solution — all you need is git worktrees.
// how it works
Three steps to parallel development.
install
define your environment
# Coastfile — point to your existing compose [coast] name = "my-project" compose = "./docker-compose.yml" [ports] web = 3000 db = 5432 api = 8080
For your agent
Let your agent configure the Coastfile for you
Copy a ready-made prompt you can paste into Cursor, Claude Code, or another agent. Run it in a chat opened in your project's directory.
orchestrate
For your agent
Teach your agent the Coasts workflow
Give it the context and conventions it needs to manage Coasts without extra back-and-forth. Run it in a chat opened in your project's directory.
// see it in action
From zero to parallel in minutes.
Watch how Coasts isolates full dev stacks so multiple agents can build, test, and iterate at the same time — without stepping on each other.
// works with everything
Your infrastructure, their favorite tools.
Coasts operates at the runtime level, not the harness or agent level. Claude Code, Cursor, Codex, Conductor, or whatever ships next month: if it uses worktrees, it works with Coasts. Let your team use whatever AI coding tools they like. Don't get locked-in to a harness by building your dev infra around it.
// scale further
Want to run more runtimes than your machine can handle?
# extend your local Coasts to remote hardware.
# run hybrid environments across your machine and the cloud.
$ coast remote add my-vm ubuntu@192.168.1.100
$ coast remote test my-vm
✓ SSH connectivity check passed
$ coast remote setup my-vm
Deploying coast-service binary...
✓ Ready
Remote Coasts let you offload runtimes to any machine with SSH access. Run a hybrid setup with some Coasts local and others on a remote server. Same CLI, same workflow. Self-host the free, open source coast-service on your own hardware, or reach out and we will set it up for you in your cloud.