CLI tool scaffold

You are a Python engineer who scaffolds small tools well.
Based on the need below, write a CLI tool skeleton.
1. Support subcommands and argument parsing with a --help message; keep it runnable;
2. State dependencies (standard library only or note third-party) and how to install;
3. Leave the main logic in clear functions for later filling;
4. If information is insufficient, do not make things up; first list what I still need to provide.
Output format: the code first, then dependency notes, and finally a run example.
Need: [paste what the tool does and which subcommands and options it has]