The moment you assemble a command as a string and hand it to a shell, every metacharacter in it becomes live: a semicolon, backtick, $(), or pipe in user input runs a second command of the attacker's choosing. Quoting and escaping are a losing arms race against shell parsing rules. The durable fix is to never involve a shell: pass the program and its arguments as a list so the operating system executes exactly one binary with exactly those args.
Command Injection Defense is a community-contributed Claude Code skill in the general-misc sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/command-injection-defense/ and loads when your prompt matches the skill's trigger.
When to invoke it: Use when a program shells out to another binary, especially with any value that came from a user, a file, or the network.
The Command Injection Defense Claude Code skill is built for Claude Code users and developers across all disciplines looking for general-purpose AI assistance. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 196,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).
mkdir -p ~/.claude/skills/command-injection-defense curl -L https://claudskills.com/skills/command-injection-defense/SKILL.md \ -o ~/.claude/skills/command-injection-defense/SKILL.md
Or just download SKILL.md directly and drop it into ~/.claude/skills/command-injection-defense/. Claude Code auto-discovers it on next session.
Skills live at ~/.claude/skills/command-injection-defense/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\command-injection-defense\SKILL.md on Windows. See the full install guide for step-by-step instructions.
Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →
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.
For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.
SKILL.md from the source repository to ~/.claude/skills/command-injection-defense/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Command Injection Defense is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the General category. Learn more at /learn/what-is-a-claude-skill/.If you reference this skill in a blog post, paper, or documentation, you can cite it as:
@misc{command-injection-defense-2026,
author = {Amey-Thakur},
title = {Command Injection Defense [Claude Code skill]},
year = {2026},
publisher = {ClaudSkills},
url = {https://claudskills.com/skills/command-injection-defense/}
}Grade A · scanned 2026-09-28 — free static scan against the OWASP Agentic Skills Top 10.
The scan flagged 1 of 10 categories (execution), including lower-severity patterns. Patterns shown inside code fences are weighted as examples rather than instructions — read the grading methodology for what this does and does not guarantee.
Browse all General skills in the ClaudSkills registry, or explore these other picks from the same category:
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SKILL.md files, not affiliated with, endorsed by, or sponsored by Anthropic.