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 102,166 GitHub stars across a repository of 13 listed skills.
github.com/addyosmani/agent-skills/skills/security-and-hardening (opens in a new tab)
- Multi-skill repo
- Plugin marketplace
- Security
- Actively maintained
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-skillsIn 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 projectsStandalone 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 projectsSource (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.
Code Review And Qualityaddyosmani/agent-skills
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What is the Security And Hardening skill?
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 102,166 GitHub stars across a repository of 13 listed skills. Its SKILL.md lives at github.com/addyosmani/agent-skills/skills/security-and-hardening.
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 3, 2026. Its latest release is 0.6.12. appsgit only lists skills from repositories with a commit in the last six months.