Coasts is an open‑source tool that creates isolated local runtimes—called Coasts—for each Git worktree, giving each stack its own ports, network, and services. By containerizing each worktree, developers can run multiple AI‑assisted coding agents or development stacks in parallel on a single machine without port collisions or resource contention, using simple CLI commands and a TOML‑based Coastfile.
Funding
Funding not disclosed
Founders
Product
Problem
Developers using Git worktrees can isolate code changes, but all worktrees share the same local runtime, leading to port collisions, shared resource contention, and cumbersome environment switching when multiple agents or processes run in parallel.
Solution
Coasts provides a free, open‑source tool that creates fully isolated local runtimes—called Coasts—for each worktree. Each Coast runs in its own containerized host with independent ports, networks, and services, allowing multiple agents or development stacks to operate side‑by‑side on a single machine. The system integrates with any agentic coding tool that works with Git worktrees, requiring only a Coastfile to define runtime configuration. Developers can build, test, and iterate concurrently without manual port remapping or resource conflicts, and can switch between isolated environments instantly via simple CLI commands.
Target Audience
Primary users are software engineers and development teams that employ Git worktrees and AI‑assisted coding agents, especially those running complex docker‑compose stacks or needing parallel development environments.
Features
- Containerized host per worktree delivering independent ports, networks, and volumes
- Simple TOML‑based Coastfile to map existing docker‑compose or non‑containerized setups
- CLI commands (`coast build`, `coast run`, `coast checkout`) for fast creation, execution, and switching of isolated runtimes
- Dynamic port allocation with optional canonical port remapping for seamless access
- Compatibility with any AI coding agent (Claude Code, Cursor, Codex, etc.) that uses worktrees—no harness‑side changes required
- Supports both macOS and Linux with Docker Desktop or Docker Engine + Compose plugin
- Open‑source MIT license with optional custom local configurations, cloud deployments, and infrastructure support for teams