PM Skills vs prompt marketplaces — an honest comparison

Paid prompt stores sell single-use text; this library ships versioned, tested, self-verifying skills — free.

Criterion	PM Skills	The alternative
Price	Free forever (MIT), 526 skills	Typically $2–10 per prompt
Quality bar	SkillSpec L3 CI gate: declared inputs, output templates, quality checks, anti-patterns	Marketplace review varies; often none
Verification	Open validator, security scan, public eval scores, worked examples	Star ratings
Updates	Versioned in git; installed copies refresh via `outdated`	Buy again, maybe
Portability	Claude, ChatGPT, Gemini, Cursor + 8 more via exports; MCP; API	Copy-paste, single tool

Where the alternative wins: Where marketplaces win: niche prompts for image models and one-off creative tasks — this library deliberately doesn't cover generative art. For professional documents and decisions, tested-and-free beats rated-and-paid.

▶ Judge for yourself — run a skill free