What problem does it solve? Building command-line tools in TypeScript often means hand-rolling argument parsing, help text, and validation. This Skill guides an agent to construct type-safe CLIs with the Effect v4 CLI module, covering positional arguments, named flags, subcommands, prompts, and dependency injection without ad-hoc parsing code. ## Core Features & Use Cases - Typed Arguments and Flags: Define positional arguments and named flags with constructors like Argument.String, Flag.Int, and Flag.Boolean, plus combinators for defaults, aliases, validation via Schema, and fallback prompts or env config. - Subcommands and Shared Flags: Compose nested command trees with Command.withSubcommands, grouped listings, and Command.withSharedFlags so parent options flow into subcommand handlers. - Dependency Injection and Runtime: Wire handlers to services with Command.provide, and run the CLI through Command.run with NodeServices.layer and NodeRuntime.runMain. - Use Case: Scaffold a task manager CLI where 'tasks create "Ship 4.0" --priority high' parses typed input, inherits a shared --workspace flag, and executes an Effect handler with injected platform services. ## Quick Start Ask the agent to build an Effect CLI command named 'greet' that accepts a name flag and prints a greeting using Command.make and NodeRuntime.runMain.
