Only 17.7% of the catalog is popular enough to be graded, 1 in 32 graded skills is unsafe, and the risk lives in the long tail — plus a new agent-native attack surface.
We Security-Graded 117,854 AI Agent Skills. Here's What We Found. | Agent Skills Hub
Only 17.7% are popular enough to be graded. Among graded skills, 1 in 32 is unsafe. The risk lives in the long tail.
agentskillshub.top
The uncomfortable part isn't the skills that are unsafe. It's how few have been checked at all.
Installing an AI agent skill or MCP server means handing untrusted code your shell, your environment variables, and increasingly your agent's own config and memory. Discovery is easy — there are tens of thousands to pick from. Knowing whether the one you found is safe to run is not.
So we scanned the whole catalog. Here's the honest picture.
📄 This is a cross-post. Canonical version (with charts): agentskillshub.top/blog/securing-117k-ai-skills
How we scanned
A rule-based scanner, modeled on SlowMist's Agent Security Framework and its 11 red-flag categories. It runs static checks over each skill's README and code, looking for concrete patterns: outbound data exfiltration (curl -d $(...)), credential harvesting (env | grep -i token), reading .env / .ssh / .aws, curl | sh install scripts, privilege escalation, persistence, and secret-exfil combos. Each skill gets a grade — safe / caution / unsafe / reject — plus the specific flags it tripped. Skills with no README or too new to fetch stay unknown.
This is deliberately a first layer: it catches patterns, not intent. At 117K scale, the pattern layer is what makes the catalog auditable at all.
Finding 1 — 82% of the catalog has never been graded
Of 117,854 indexed skills, only 20,853 (17.7%) clear 5 stars — the threshold where a skill is popular enough to be worth grading. The other ~97,000 are effectively unaudited.
"We have 117K skills" is not a feature. The number that matters is how many you can actually trust, and for the long tail the honest answer is: nobody has looked.
Finding 2 — Among graded skills, 1 in 32 is unsafe or worse
| Grade | Share |
|---|---|
| 🟢 safe | 85.5% |
| 🟡 caution | 5.3% |
| 🔴 unsafe | 3.0% |
| ⛔ reject | 0.1% |
| ⚪ unknown | 6.1% |
8.4% carry a security concern. 3.1% — about 1 in 32 — are unsafe or reject. At this catalog's size that's ~650 graded skills you genuinely should not run blind, sitting in the same search results as everything else.
Finding 3 — Popularity predicts safety. The risk lives in the long tail.
| Stars | Unsafe / reject |
|---|---|
| 5–20★ | 4.1% |
| 20–100★ | 3.7% |
| 100–1,000★ | 0.9% |
| 1,000★+ | 0.4% |
The skill you've heard of is almost certainly fine. The danger is the obscure 7-star repo you'd grab from a search for a niche task — exactly the moment a directory is supposed to help, and usually doesn't.
Finding 4 — The red flags include a new, agent-native attack surface
Most common flags among a sample of 1,000 flagged skills:
| Flag | Count |
|---|---|
| sudo usage | 483 |
| background service install | 152 |
| curl | shell | 99 |
| agent config theft | 87 |
| tunnel service | 66 |
| eval() | 52 |
| sensitive env vars | 34 |
| agent memory theft | 23 |
| backdoor install | 11 |
The classic shell risks dominate. But look at agent config theft (87) and agent memory theft (23): skills that read your agent's configuration and memory files. That's not a server exploit — it's a new attack surface that only exists because you're running an agent. Your Claude/MCP config, your stored context, your credentials-by-proxy. The threat model moved, and most directories haven't noticed.
What to do about it
Check the trust signal before you install, from where you already work:
npx @agentskillshub/cli search "postgres mcp" --safe
npx @agentskillshub/cli audit owner/repo
Every result carries its grade and the specific flags it tripped. --safe hides anything unaudited or worse.
The honest caveats (because that's the whole point)
- Our 3% is a floor, not a ceiling. Academic deep-analysis (Liu et al., 2026, arXiv:2601.10338) puts the agent-skill vulnerability rate at 26.1%, because they analyze semantics, not just patterns. Our rule-based first pass deliberately under-claims. Read 3% as the lower bound of a bigger problem.
- ⚪ unknown is not "probably fine." It means no one has checked. 97K of the catalog is unknown. We label it gray and don't dress it up.
- All numbers are reproducible. Every grade is visible on the site and via the CLI. Re-derive them yourself.
A trust layer that only told you the good news wouldn't be one. The most useful thing we can say about 97,000 skills is that we don't yet know — and we'll tell you that to your face.
Full writeup with charts: We security-graded 117,854 AI agent skills. Check any skill before you install: npx @agentskillshub/cli audit owner/repo.