Open CLI Framework

An open source framework for building command line interfaces in Node.js and TypeScript, created and maintained by a major cloud platform provider. The framework enables developers to scaffold fully functional CLIs with a single command, providing out-of-the-box functionality for argument parsing, flag handling, command testing, and automatic documentation generation including help text, man pages, and completion scripts for bash, zsh, and fish shells. The architecture supports both simple single-command tools and complex multi-command CLIs with nested subcommands, similar to how tools like docker, git, or gh structure their command trees. Commands are defined as TypeScript classes with typed properties for flags and arguments, automatically generating parsing logic, validation, and help output from decorator-style declarations. The plugin system allows extending existing CLIs with additional commands at runtime, supporting npm-based plugin distribution where users install plugins via a command like mycli plugins install plugin-name. This enables third-party extensibility for any CLI built with the framework. Hooks provide lifecycle integration points for executing code before or after commands, enabling cross-cutting concerns like analytics, telemetry, or setup validation. The framework includes built-in support for command discovery via file system scanning or explicit manifest configuration, topic-based command grouping, and command aliases. Production CLIs built with this framework include widely used developer tools from cloud platforms, communication APIs, and e-commerce platforms. The framework handles auto-updates through an update notifier system, supports both CommonJS and ESM output, and provides a comprehensive testing API for asserting command output, flag parsing, and exit codes.