Commands

Daily use

CommandDescription
rat <lang>Open REPL (auto-starts kernel)
rat run <runtime> '<code>'Execute code
rat look <runtime> [--at SYM]Inspect namespace
rat tail <runtime>Recent activity
rat pickInteractive kernel picker
rat cancel <runtime>Interrupt execution
rat reset <runtime>Clear namespace
rat restart <runtime>Fresh start

Setup

CommandDescription
rat install <lang> [<lang>...]Set up runtimes + deps
rat setupInteractive wizard
rat add <name> [dir]Register named runtime
rat remove <name> [--all]Delete state entry

Management

CommandDescription
rat status [-v]What’s running
rat start <runtime>Start a kernel
rat stop <runtime> [--all]Stop a kernel
rat serve <name> [--http]MCP server (for app builders)
rat doctor [<lang>]Diagnostics
rat versionVersion info
rat updateUpdate rat