Semgrep Custom Rule Builder 3

Quality score: 70/100 · Category: Security · Sub-category: appsec-tools

lang:javascript

Creates custom Semgrep SAST rules using the semgrep CLI and rule schema YAML format. Supports pattern-either, metavariable-regex, and taint-mode tracking for detecting framework-specific vulnerabilities in Python, Go, and JavaScript.

What this skill does

Semgrep Custom Rule Builder 3 is a production-ready Claude Code skill (quality score 70/100) in the appsec-tools sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/semgrep-custom-rule-builder-3/ and loads when your prompt matches the skill's trigger.

Who uses this skill

The Semgrep Custom Rule Builder 3 skill is built for security engineers, penetration testers, DevSecOps practitioners, and development teams hardening codebases and infrastructure. It is part of the open ClaudSkills registry, a community-curated catalog of 15,000+ capabilities you can install for Claude Code — the Claude CLI agent.

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/semgrep-custom-rule-builder-3
curl -L https://claudskills.com/skills/semgrep-custom-rule-builder-3/SKILL.md \
  -o ~/.claude/skills/semgrep-custom-rule-builder-3/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/semgrep-custom-rule-builder-3/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/semgrep-custom-rule-builder-3/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\semgrep-custom-rule-builder-3\SKILL.md on Windows. See the full install guide for step-by-step instructions.

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

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Part of ClaudSkills — the open registry for Claude Code skills. · What's New · Install guide · About · llms.txt

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