vet-skills

Check agent skills and MCP servers before they run. Verdicts come from KillerSkills; the policy is yours or your org's.

npm i -g vet-skills                          # the CLI (Node 20+)
vet-skills hook install claude-code          # intercept every install in Claude Code
vet-skills check <skill>                     # or just ask before you add one
vet-skills publish ./my-skill                # org members: detonate + list in the private registry

Use it as an MCP server

Give any agent the verdicts directly, so it checks a skill or MCP server before installing it and can pick a verified alternative. Read-only, no account, no API key. Tools: check_skill (verdict, score, what the sandbox saw, top findings, last safe version) and search_skills (the index by keyword, with verdicts).

Claude Code

claude mcp add killerskills -- npx -y vet-skills mcp

Cursor: ~/.cursor/mcp.json (or .cursor/mcp.json in a project)

{
  "mcpServers": {
    "killerskills": { "command": "npx", "args": ["-y", "vet-skills", "mcp"] }
  }
}

Claude Desktop: Settings → Developer → Edit Config (claude_desktop_config.json)

{
  "mcpServers": {
    "killerskills": { "command": "npx", "args": ["-y", "vet-skills", "mcp"] }
  }
}

VS Code: .vscode/mcp.json

{
  "servers": {
    "killerskills": { "type": "stdio", "command": "npx", "args": ["-y", "vet-skills", "mcp"] }
  }
}

Windsurf: ~/.codeium/windsurf/mcp_config.json, same mcpServers block as Cursor. Codex: ~/.codex/config.toml

[mcp_servers.killerskills]
command = "npx"
args = ["-y", "vet-skills", "mcp"]

Then ask your agent: "Before you add that MCP server, check it with KillerSkills." Requires Node 20+. Index: 16,000+ skills and MCP servers from skills.sh, ClawHub, npm, PyPI, the Docker MCP Catalog and Claude Code plugin marketplaces, each run in a honeypot sandbox. Browse them at killerskills.ai.

See what is already configured

vet-skills discover            # every MCP server, skill, plugin and hook on this machine, with verdicts

Reads Claude Code, Cursor, Windsurf, Claude Desktop, Gemini CLI and Codex configs locally. Each server and skill name is looked up for its verdict; nothing else leaves the machine. When you are enrolled in an org, the list of names is also reported to your team's Discovery page. Environment values, arguments and file contents never are.

What it does

Every skills add, claude plugin install, and claude mcp add is resolved to an artifact hash, looked up, and evaluated against your policy before it runs:

$ vet-skills check deploy-helper
Resolving deploy-helper …
vet-skills 0.7.4 · policy acme/default-strict

 BLOCKED  14/100 deploy-helper@2.3.1 · devtools-cloud · 4,210 installs

Observed in sandbox (3 scenarios, 38s):
  ✕ network    telemetry-cdn.xyz — undeclared
  ✕ memory     wrote agent memory (1)
  ✕ filesystem reads ~/.ssh/id_ed25519, ~/.aws/credentials, ~/.npmrc
  ! tools      shadows github.create_pr

Policy acme/default-strict:
  ✕ publisher blocked      devtools-cloud is on the block list

✕ Blocked deploy-helper@2.3.1 · publisher devtools-cloud is blocked by policy
Pin instead: deploy-helper@2.2.4 (score 88)

Decisions: allow, sandbox (install with restrictions), approval required (the install waits for a reviewer), block (with the last safe version named), defer (unscored: detonate first), observe (org enforcement off; logged only).

Fail-open

If the verdict API is unreachable and nothing is cached, the policy's offline rule applies. The default is allow with a warning: an outage on our side never stops your work. Set offline: block in your policy to fail closed.

Solo vs. org

Solo: a personal policy in ~/.vet-skills/policy.yaml (vet-skills policy show). Nothing is sent except verdict lookups (skill name, version, hash) and an anonymous client id.

Org: vet-skills join <org> --token <enroll token> --email you@company.com switches to the org policy. From then on the hook also reports installed skill names, versions, hashes, and decisions to your org dashboard. Never code, prompts, environment variables, or file contents. vet-skills leave reverts.

Commands

Environment: KILLERSKILLS_API (default https://killerskills.ai), VET_SKILLS_HOME (default ~/.vet-skills), NO_COLOR.