modbender scan-skill -- Individual Skill Analyzer
Perform deep security analysis of a single skill directory before installation. Checks for all known injection techniques from AI agent security research.
What to do
Run the scanner against the target skill directory:
python3 "$SKILL_DIR/scripts/scan_skill.py" "$ARGUMENTS"
Where $ARGUMENTS is the path to the skill directory to analyze.
If no argument is provided, prompt the user for the path to the skill they want to scan.
What it checks
- SKILL.md frontmatter analysis (dangerous field combinations, hidden skills, pre-approved tools)
- Hidden HTML comments with imperative instructions
- Shell command patterns (remote-code-pipe-to-shell, encoded payloads)
- Description persistence triggers (forced repeated execution keywords)
- Supporting files analysis (scripts/ directory contents, executable permissions)
- Dynamic context injection (preprocessor command execution)
- Encoding and obfuscation (base64, hex, zero-width characters)
- Instruction override attempts (context manipulation, role impersonation)
Output
Structured report with severity-ranked findings and specific recommendations per finding. Includes frontmatter analysis summary and supporting file inventory.
When to use
- Before installing a skill from a public repository or marketplace
- When reviewing a skill contributed by an external party
- As part of security review before adding skills to your agent configuration