SkillTotal
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Agent Skill Security Scanner

An agent skill — a SKILL.md plus its bundled scripts — runs inside your agent with its permissions. Paste its repository URL or package on the home page, or upload the skill folder as a ZIP, and see what its code actually does — and whether it exceeds what it declares — before you install it.

Scan a component — free →

Skill-specific risks it catches

  • Undeclared capabilities: the skill's allowed-tools say one thing, but the bundled code shells out, reaches the network, or writes files anyway — a least-privilege violation.
  • Hidden instructions: prompt-injection or tool-poisoning text in SKILL.md that steers your agent — caught even behind look-alike or zero-width characters.
  • Dangerous bundled scripts: shell/exec, credential-path access, or decode-and-run payloads in the scripts shipped alongside the skill.

Evidence, not guesswork

Detection is deterministic (regex + AST), your code is never executed, and every finding points at the exact file and line. The declared-vs-actual check is structural — it compares the skill's own declaration to what the code does, with no LLM inferring intent.

Scanned agent skills

Learn it hands-on

Try the interactive prompt injection lab to make a guarded agent leak its secret — then see the defenses.

FAQ

What is an agent skill?
An Anthropic Agent Skill is a folder with a SKILL.md (instructions plus frontmatter) and optional bundled scripts/resources, loaded by agents such as Claude Code, Gemini CLI and others. It runs with your agent's permissions.
What does “undeclared capability” mean?
A SKILL.md can declare allowed-tools — a least-privilege list. If the bundled code uses a capability those tools do not grant (for example it runs a shell while declaring only Read), SkillTotal flags the mismatch.
How do I scan a skill — and does it run the skill?
Nothing is installed or executed; analysis is fully static. Paste the skill's GitHub/GitLab repo URL (or npm/PyPI package) on the home page, or zip the skill folder and upload it on the Scan a skill or project page.