AGENT SKILLS · PRE-INSTALL REVIEW

A valid skill can still be dangerous.

Paste SKILL.md and review two separate questions: does it follow a portable structure, and does its content request risky tools, hidden authority, credential access, or remote execution?

FrontmatterPrompt injectionTool scopeLocal-only

STATIC SKILL AUDIT

SKILL.md scanner

SKILL.md0 lines · ~0 tokens

Checks portable frontmatter, activation quality, tool permissions, suspicious instructions, secret patterns, remote URLs, shell execution, and context size.

Structure

Required delimiters, name and description, portable naming, unknown fields, and instruction body.

Authority

Hidden overrides, attempts to suppress approval, requests for credentials, and instructions to conceal actions.

Execution

Shell downloads, privilege escalation, destructive commands, tool scope, and untrusted remote dependencies.

Context quality

Activation phrases, actionable steps, references, excessive length, and claims the scanner cannot verify.

TRUST BOUNDARY

Skills are instructions plus supply chain.

A skill can influence when an agent activates, which tools it uses, what files it reads, and where it sends data. Static text review catches visible warning signs, but installation trust also depends on the publisher, referenced files, scripts, version history, and the behavior of every allowed tool.

Scan before install

Read the entire selected skill
Inspect scripts and referenced resources
Review allowed tools against the task
Search for network destinations and secrets
Pin the source and record provenance

Recheck after updates

Diff instructions and frontmatter
Audit new scripts and binary assets
Review expanded tool permissions
Retest activation boundaries
Remove abandoned or duplicated skills

SKILL.md validatorPortable frontmatter and structure →Agent Skill security guideThreat model and review checklist →Skill description guideWrite reliable activation text →

PURPOSE & METHODOLOGY

A focused tool, with the context to use it well

Skill Guard was created to review agent skill packages and SKILL.md files for security and quality issues. It is intended for developers evaluating reusable AI-agent skills before installation. The tool is free, requires no account, and is paired with original explanations so you can understand the result rather than copy an unexplained output.

How to use the result

Start with a sample or a non-sensitive copy of your data, run the check, and review every finding before changing a production project. Findings distinguish suspicious behavior from ordinary tooling and include manual-review guidance. Automated checks reduce review time but do not replace inspecting code and permissions. Specifications and software evolve, so confirm high-impact decisions against the linked primary documentation.

Privacy and limitations

skill instructions and package metadata is processed in your browser wherever the tool page states that local processing is used. Avoid entering passwords, access tokens, personal data, or confidential material. Automated output may be incomplete because it cannot know your entire deployment, threat model, or organizational policy.

Independent and transparent

This is an independent developer resource, not an official certification service. Source code and issue tracking are available on GitHub. Read more about the project, review the privacy policy, or report an error.