Both in the frontend and the backend, I've usually used "If it calls your code, it's a framework, if you call its code, it's a library", and would seem to fit here too. An argument parser you'd call from your main method, then do stuff with what it returns. In Crust, it seems you instead setup the command + what will happen when it's called, then let the framework call your code.

Hi, I called it "CLI framework" because it is more of a ecosystem of modules that contains everything you need to build a CLI, argument parsing is just part of it. The @crustjs/core module is the argument parser, and there are more modules such as @crustjs/skills that would derive agent skills from your command definition, @crustjs/store that state persistent and so on

good point.

we’re using “framework” intentionally because it goes beyond argument parsing. crust handles parsing, but also:

type inference across args + flags end to end compile-time validation (so mistakes fail before runtime) plugin system with lifecycle hooks (help, version, autocomplete, etc.) composable modules (prompts, styling, validation, build tooling) auto-generates agent skills and modules from the CLI definitions

so it sits a layer above a traditional arg parser like yargs or commander, closer to something like oclif, but much lighter and bun-native.