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Security And Hardening

Security And Hardening is an agent skill (a SKILL.md file) from addyosmani/agent-skills. Hardens code against vulnerabilities. Use when auditing an input handler for vulnerabilities, when handling user input, authentication, data storage, or external… It works with Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot and OpenCode and has 110,586 GitHub stars across a repository of 13 listed skills.

github.com/addyosmani/agent-skills/skills/security-and-hardening (opens in a new tab)

Data as of from the GitHub API and skills.sh; description from the skill's SKILL.md. Report an error

View on GitHub (opens in a new tab)View on skills.sh (opens in a new tab)

Add this skill

Claude

This repository is a Claude Code plugin marketplace. In Claude Code:

/plugin marketplace add addyosmani/agent-skills
/plugin install agent-skills@addy-agent-skills

In the Claude apps, zip the security-and-hardening folder and upload it under Customize > Skills > + > Upload a skill (code execution must be on).

ChatGPT / Codex

Codex reads skills from .agents/skills/ in a repo or ~/.agents/skills/ for every project:

git clone --depth 1 https://github.com/addyosmani/agent-skills.git
cp -r agent-skills/skills/security-and-hardening .agents/skills/security-and-hardening   # repo; ~/.agents/skills for all projects

Standalone skills also load in the ChatGPT desktop app.

Cursor

Cursor loads skills from .cursor/skills/ (or ~/.cursor/skills/) and also reads .claude/skills/:

git clone --depth 1 https://github.com/addyosmani/agent-skills.git
cp -r agent-skills/skills/security-and-hardening .cursor/skills/security-and-hardening   # project; ~/.cursor/skills for all projects

Source (checked Oct 7, 2026): code.claude.com/docs/en/skills (opens in a new tab), code.claude.com/docs/en/plugin-marketplaces (opens in a new tab), support.claude.com/en/articles/12512180-using-skills-in-claude (opens in a new tab), learn.chatgpt.com/docs/build-skills (opens in a new tab), cursor.com/docs/context/skills (opens in a new tab)

What this skill does

Hardens code against vulnerabilities. Use when auditing an input handler for vulnerabilities, when handling user input, authentication, data storage, or external integrations, or when checking a login flow is safe against the OWASP Top Ten. Use when building any feature that accepts untrusted data, manages user sessions, or interacts with third-party services.

When it triggers

  • Use when auditing an input handler for vulnerabilities, when handling user input, authentication, data storage, or external integrations, or when checking a login flow is safe against the OWASP Top Ten.
  • Use when building any feature that accepts untrusted data, manages user sessions, or interacts with third-party services.
  • Use when auditing dependencies for known vulnerabilities, triaging package-manager audit findings, or assessing supply-chain risk in a new package.

More skills in addyosmani/agent-skills

13 skills are listed from this repository.

Similar skills

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All Security

FAQ

Security And Hardening FAQ

Still curious? Email info@appsgit.com.

How do I install the Security And Hardening skill?

In Claude Code, run /plugin marketplace add addyosmani/agent-skills and then /plugin install agent-skills@addy-agent-skills. For Codex or Cursor, copy the security-and-hardening folder into .agents/skills/ or .cursor/skills/.

Is the Security And Hardening skill free?

Yes. The repository is open source under the MIT license.

Is Security And Hardening maintained?

The repository's most recent commit was on Oct 13, 2026. Its latest release is 0.6.13. appsgit only lists skills from repositories with a commit in the last six months.