Currently, mo cannot open directories.

$ mo ./.kiro/specs/example-spec
Error: file not found: /Users/syumai/src/github.com/syumai/example/.kiro/specs/example-spec
Usage:
...

However, when a directory is specified, the intent is almost always "I want to open and watch all Markdown files added to this directory."

While it would be fine to automatically watch **/*.md (or just *.md) in the given directory, simply suggesting the command and letting the user proceed with Enter key would be convenient enough.

$ mo ./.kiro/specs/example-spec
Error: .kiro/specs/example-spec is a directory, not a file.

Would you like to watch this directory instead?
  mo --watch '.kiro/specs/example-spec/**/*.md'

Proceed? [Y/n]: 

Watching .kiro/specs/example-spec/**/*.md ...

It would be great if you could consider this. Thanks!