Skill Portability Checker

What it does

Skills with companion scripts (.py, .sh) can silently fail on machines where their dependencies aren't installed. A skill written on macOS may call brew, pbcopy, or use /usr/local/bin paths that don't exist on Linux. A Python script may import pandas on a system without it.

Skill Portability Checker:

1. Scans companion scripts for OS-specific patterns and external binary calls
2. Checks whether those binaries are present on the current system (PATH lookup + which)
3. Cross-checks against the skill's declared os_filter: frontmatter field (if any)
4. Reports portability issues before the skill fails at runtime

Frontmatter field checked

---
name: my-skill
os_filter: [macos]   # optional: ["macos", "linux", "windows"]
---