Agent skill

Security Hardening

by bolivian-peru in bolivian-peru/os-moda

Continuous security posture assessment. An agent skill from bolivian-peru/os-moda.

Apache-2.0Auto-check passedSecurity

Install Security Hardening

skills CLI

$ npx skills add bolivian-peru/os-moda --skill security-hardening -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install bolivian-peru/os-moda security-hardening --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/bolivian-peru/os-moda.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/security-hardening .claude/skills/security-hardening && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "security-hardening" agent skill from https://github.com/bolivian-peru/os-moda/tree/main/skills/security-hardening into .claude/skills/security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "security-hardening", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/bolivian-peru/os-moda/tree/main/skills/security-hardening

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add bolivian-peru/os-moda --skill security-hardening -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install bolivian-peru/os-moda security-hardening --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/bolivian-peru/os-moda.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/security-hardening .agents/skills/security-hardening && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "security-hardening" agent skill from https://github.com/bolivian-peru/os-moda/tree/main/skills/security-hardening into .agents/skills/security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "security-hardening", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add bolivian-peru/os-moda --skill security-hardening -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install bolivian-peru/os-moda security-hardening --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/bolivian-peru/os-moda.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/security-hardening .cursor/skills/security-hardening && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "security-hardening" agent skill from https://github.com/bolivian-peru/os-moda/tree/main/skills/security-hardening into .cursor/skills/security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "security-hardening", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/bolivian-peru/os-moda.git --path skills/security-hardening

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add bolivian-peru/os-moda --skill security-hardening -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install bolivian-peru/os-moda security-hardening --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/bolivian-peru/os-moda.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/security-hardening .gemini/skills/security-hardening && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "security-hardening" agent skill from https://github.com/bolivian-peru/os-moda/tree/main/skills/security-hardening into .gemini/skills/security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "security-hardening", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install bolivian-peru/os-moda security-hardening

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add bolivian-peru/os-moda --skill security-hardening -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/bolivian-peru/os-moda.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/security-hardening .github/skills/security-hardening && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "security-hardening" agent skill from https://github.com/bolivian-peru/os-moda/tree/main/skills/security-hardening into .github/skills/security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "security-hardening", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add bolivian-peru/os-moda --skill security-hardening -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install bolivian-peru/os-moda security-hardening --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/bolivian-peru/os-moda.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/security-hardening .opencode/skills/security-hardening && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "security-hardening" agent skill from https://github.com/bolivian-peru/os-moda/tree/main/skills/security-hardening into .opencode/skills/security-hardening/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "security-hardening", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: security-hardening
GitHub stars: 119
Token cost: ~819 tokens
SKILL.md length: 173 words
Files: 1
Skills in repo: 17
Repo updated: Jun 24, 2026
First seen: Oct 7, 2026
Licence: Apache-2.0

At a glance

Continuous security posture assessment. An agent skill from bolivian-peru/os-moda.

Tasks that involve Security review
SKILL.md covers Security Scan Checklist, Scoring, Auto-Fix Actions (safe, always… and Approval-Required Actions, plus 1 more section
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Security Hardening is an agent skill from bolivian-peru/os-moda. Continuous security posture assessment. Scores the system, auto-fixes safe issues, proposes fixes for risky ones. Every change audited.

Its SKILL.md is about 820 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Security, covering Security review. The repository describes itself as: An operating system built for AI agents — talk to your NixOS server instead of SSH-ing in. Typed, audited tool access with atomic rollback on every change. Research-grade; run it… The licence is Apache-2.0.

When your agent uses it

Tasks that involve Security review

Example prompts

“/security-hardening”

What it can do on your machine

Read from SKILL.md and the folder at commit b8e418f. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are nix).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Security Hardening loads about 819 tokens when it runs. Until then it costs about 39 tokens; SKILL.md has 173 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~39
When it runs · the whole SKILL.md, loaded when a task matches: ~819

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from bolivian-peru/os-moda at commit b8e418f, republished under its Apache-2.0 licence (© bolivian-peru). 173 words, ~819 tokens.

Download SKILL.mdSave it as .claude/skills/security-hardening/SKILL.md (or your agent's skills folder).

name: security-hardening
description: Continuous security posture assessment. Scores the system, auto-fixes safe issues, proposes fixes for risky ones. Every change audited.
tools: shell_exec, system_health, journal_logs, service_status, network_info, file_read, file_write, memory_store, memory_recall, event_log
activation: auto

Security Hardening Skill

Continuous security scoring and automated hardening.

Security Scan Checklist

Run these checks and score each one:

Network (30 points)

shell_exec({ command: "ss -tlnp" })

No unnecessary ports exposed (+10)
PostgreSQL/Redis/etc bound to localhost only (+10)
Firewall enabled with explicit allowlist (+10)

SSH (25 points)

shell_exec({ command: "sshd -T 2>/dev/null | grep -E 'passwordauth|permitroot|x11forwarding|maxauthtries'" })

Password auth disabled (+10)
Root login disabled or key-only (+5)
X11 forwarding disabled (+5)
MaxAuthTries <= 3 (+5)

Failed auth attempts

journal_logs({ unit: "sshd", since: "7 days ago", priority: "warning" })
shell_exec({ command: "journalctl -u sshd --since '7 days ago' | grep -c 'Failed password'" })

System (25 points)

Automatic security updates enabled (+10)
No world-writable files in /etc (+5)
NixOS generations < 30 (clean system) (+5)
No setuid binaries outside expected set (+5)

Audit (20 points)

agentd ledger intact (hash chain valid) (+10)
All recent changes have audit entries (+10)

Scoring

Calculate: (earned_points / 100) * 100

Present as:

Security Score: 78/100

Auto-fixed (safe, no approval needed):
  ✅ Enabled fail2ban (NixOS config added)
  ✅ Set MaxAuthTries to 3
  ✅ Blocked 5 IPs with repeated failed logins

Needs your approval:
  ⚠️ Port 5432 exposed publicly — close it? (saves 10 pts)
  ⚠️ Enable automatic nixpkgs security channel

Won't touch without discussion:
  🔴 Root SSH enabled (you may need this for deploys)

Auto-Fix Actions (safe, always do these)

Enable fail2ban

nix

services.fail2ban = {
  enable = true;
  maxretry = 3;
  bantime = "1h";
};

Block brute-force IPs

shell_exec({ command: "journalctl -u sshd --since '24h ago' | grep 'Failed' | awk '{print $(NF-3)}' | sort | uniq -c | sort -rn | head -10" })

For IPs with > 10 attempts:

nix

networking.firewall.extraCommands = ''
  iptables -A INPUT -s <IP> -j DROP
'';

Close unused ports

nix

networking.firewall.allowedTCPPorts = [ 22 80 443 ];
# Remove any port that doesn't have a matching service

Approval-Required Actions

Present a clear diff and explain the security impact:

Switching SSH to certificate auth
Enabling automatic updates
Changing firewall rules that affect application access

Weekly Report

Generate a trending security report:

Security Report — Week of Feb 17

Score: 78/100 (↑ from 65 last week)

This week:
- Blocked 142 brute-force SSH attempts from 23 IPs
- Applied 2 NixOS security patches (OpenSSH, curl)
- Closed port 3306 (MySQL was accidentally exposed)
- 0 incidents, 0 unauthorized changes

Trend: Improving. Main gap: root SSH still enabled.

Store the report in memory for historical tracking.

Files

Just SKILL.md in skills/security-hardening of bolivian-peru/os-moda.

Open the folder on GitHubat commit b8e418f

Compare with similar skills

Security Hardening next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Security Hardening compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Security Hardening this skillbolivian-peru/os-moda	119	—	~819	Automated safety check: Pass	Apache-2.0	3 mo ago
Deepsec Documentation Guidevercel-labs/deepsec	8.1k	—	~956	Automated safety check: Pass	Apache-2.0	12 days ago
Kubernetes Network Security Auditkubeshark/kubeshark	12k	—	~7.3k	Automated safety check: Notes	Apache-2.0	yesterday
Native Dependency Updatemono/SkiaSharp	5.6k	—	~4.1k	Automated safety check: Pass	MIT	yesterday
Semgrep Security Scantrailofbits/skills	7.5k	—	~3.7k	Automated safety check: Notes	CC-BY-SA-4.0	yesterday
Skillward AuditFangcun-AI/SkillWard	143	—	~2.9k	Automated safety check: Pass	Custom licence	2 mo ago

Similar skills

Deepsec Documentation Guide
vercel-labs/deepsec
Official
Points the agent at deepsec's own docs to answer questions about initializing, configuring, resuming, scanning with and extending the vulnerability scanner.
8.1k GitHub stars~956 tokensUpdated 12 days ago
SecurityAuto-check passed
Kubernetes Network Security Audit
kubeshark/kubeshark
Hunts for compromised workloads and malicious traffic in a Kubernetes cluster by sweeping network data through Kubeshark MCP, mapped to MITRE ATT&CK.
12k GitHub stars~7.3k tokensUpdated yesterday
SecurityAuto-check: notes
Native Dependency Update
mono/SkiaSharp
Update native dependencies (libpng, libexpat, zlib, libwebp, harfbuzz, freetype, libjpeg-turbo, etc.) in SkiaSharp's Skia fork.
5.6k GitHub stars~4.1k tokensUpdated yesterday
SecurityAuto-check passed
Semgrep Security Scan
trailofbits/skills
Official
Detects languages, proposes rulesets for approval, then runs the approved Semgrep scan across a codebase and merges the output into one SARIF file.
7.5k GitHub stars~3.7k tokensUpdated yesterday
SecurityAuto-check: notes
Skillward Audit
Fangcun-AI/SkillWard
Security-audit a third-party skill bundle (folder with SKILL.md, or .zip / .tar.gz archive) before installing it, using the SkillWard cloud scanner.
143 GitHub stars~2.9k tokensUpdated 2 mo ago
SecurityAuto-check passed
Security Audit
TheDecipherist/claude-code-mastery
Checks a codebase for hardcoded secrets, vulnerable dependencies, weak input handling, weak authentication and unsafe transport settings before deployment or merge.
551 GitHub stars~1.3k tokensUpdated 5 mo ago
SecurityAuto-check: notes

Questions about Security Hardening

What does Security Hardening do?

Continuous security posture assessment. An agent skill from bolivian-peru/os-moda. Security Hardening is an agent skill from bolivian-peru/os-moda. Continuous security posture assessment.

When should I use Security Hardening?

Security Hardening fits situations like: tasks that involve Security review.

How do I install Security Hardening in Claude Code?

Run `npx skills add bolivian-peru/os-moda --skill security-hardening -a claude-code`. Or copy the skill folder (skills/security-hardening in bolivian-peru/os-moda) into .claude/skills/security-hardening in your project. Claude Code loads it when a task matches its description.

How do I install Security Hardening in Codex?

Run `npx skills add bolivian-peru/os-moda --skill security-hardening -a codex`. Or copy the skill folder (skills/security-hardening in bolivian-peru/os-moda) into .agents/skills/security-hardening in your project. Codex loads it when a task matches its description.

Can I use Security Hardening in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add bolivian-peru/os-moda --skill security-hardening -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/security-hardening, .gemini/skills/security-hardening, .github/skills/security-hardening and .opencode/skills/security-hardening in your project.

What does Security Hardening need to run?

SKILL.md names no scripts, command-line tools or credentials: Security Hardening is instructions for the agent only.

Does Security Hardening access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Security Hardening safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Security Hardening use?

Security Hardening is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Security Hardening use?

About 819 tokens (SKILL.md is roughly 3.3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Security Hardening?

Skills that share tags, products or a category with Security Hardening: Deepsec Documentation Guide (vercel-labs/deepsec, 8.1k stars), Kubernetes Network Security Audit (kubeshark/kubeshark, 12k stars), Native Dependency Update (mono/SkiaSharp, 5.6k stars) and Semgrep Security Scan (trailofbits/skills, 7.5k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Security Hardening?

bolivian-peru (a GitHub user) maintains it in bolivian-peru/os-moda, which has 119 GitHub stars. The repository holds 17 skills in this directory. The repository was last updated on June 24, 2026.

Source: bolivian-peru/os-moda on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Security Hardening

Facts

At a glance

What it does

When your agent uses it

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Security Hardening Skill

Security Scan Checklist

Network (30 points)

SSH (25 points)

Failed auth attempts

System (25 points)

Audit (20 points)

Scoring

Auto-Fix Actions (safe, always do these)

Enable fail2ban

Block brute-force IPs

Close unused ports

Approval-Required Actions

Weekly Report

Files

Compare with similar skills

Similar skills

More from bolivian-peru/os-moda

Related

Questions about Security Hardening