Same experience here.

Documentation-based skills don’t really work in practice. They tend to waste tokens instead of adding value.

CLI skills are also redundant when the CLI already provides clear built-in help messages. Those help messages are usually up to date, unlike separate skills that need to be maintained independently.

If the CLI itself is confusing (and would likely be confusing for humans as well) then targeted skills can serve as a temporary workaround, a kind of band-aid.

Where skills truly shine is when agents need to understand non-generic terms and concepts: unique product names, brand-specific terminology, custom function names, and other domain-specific language.