vercel-labs/just-bash: Bash for Agents

just-bash is a TypeScript library from Vercel Labs that simulates a bash environment with an in-memory virtual filesystem, designed for AI agents needing a secure sandboxed shell. It supports a wide range of Unix commands (file ops, text processing, jq, sqlite3, Python via Pyodide), multiple filesystem backends (InMemoryFs, OverlayFs, ReadWriteFs, MountableFs), optional network access with URL allow-lists, execution protection against infinite loops, AST transform plugins, and a Vercel AI SDK integration via the companion bash-tool package. A CLI binary and interactive shell are also included.