Scope and Non-Goals

cl-cli aims for feature parity with the mainstream CLI frameworks (clap, cobra, click, argparse) on everything that is fundamentally a parsing, dispatch, help, or completion concern.

A few capabilities those frameworks offer are deliberately left to the application, because they are runtime-I/O or policy concerns rather than argument handling:

• Interactive prompting for missing values, hidden/password input, and confirmation prompts (click's prompt= / hide_input=). Reading a terminal with echo disabled is an I/O concern; clap and cobra defer it too. A handler can prompt from invocation-stdout / invocation-stderr as needed.
• Filesystem-touching validators (existence/readability checks). Declare intent with :value-hint :file / :dir for completion, and enforce with a custom :parser; whether a path must already exist is per-app policy.
• Config-file parsing (TOML/YAML). The :config layer accepts an already-parsed plist and slots it between environment variables and literal defaults (see option-value-source); choosing and reading the file format stays with the caller.
• Stdin values, progress bars, and completion-script installation are pure runtime behavior; the library gives you a --token you can special-case, the streams to draw on, and render-*-completion output to install where you like.

Everything else the reference frameworks expose — including terminal-aware color/width, value provenance, "did you mean" suggestions, and configurable exit codes — is built in and covered in the Guide.