# Sandcastle (AI) Sandcastle is a [[TypeScript]] library by [[Matt Pocock]] for orchestrating AI coding agents in isolated sandboxes. You invoke an agent with a single `sandcastle.run()` call; the library runs it in a sandbox on a configurable branch, then merges the resulting commits back into your repo. It targets parallelizing multiple AFK agents, building review pipelines, or orchestrating your own agents. ## Key aspects - **Provider-agnostic**: Docker, Podman, Vercel, or custom providers. Bind-mount providers (like Docker) mount worktrees directly; isolated providers sync via `copyIn` / `copyFileOut` - **Branch strategies**: head (direct write), merge-to-head (temporary branch), or explicit branch names - **Session capture and resume** for continued agent conversations - **Structured output** via Standard Schema validators - **Prompt system** with dynamic context (shell expressions, template substitution) and before/after lifecycle hooks - **Multi-iteration** support with completion signals and idle timeouts ## Agent support Claude Code, Codex, Pi, Cursor, OpenCode, and Copilot, each configurable (model, reasoning effort, permission modes). MIT licensed; TypeScript (tsup + vitest). ## References - https://github.com/mattpocock/sandcastle ## Related - [[Matt Pocock]] - [[AI Agents]] - [[Agentic Engineering]] - [[Docker Sandboxes]] - [[OpenSandbox]] - [[Vercel Sandboxes]] - [[Cloudflare Sandbox SDK]] - [[microVM]] - [[Claude Code]] - [[TypeScript]] - [[MIT License]]