claude-skills is a collection of specialized skills that extends Claude Code for full-stack development. Developers use it for programming languages, frameworks, infrastructure, APIs, testing, DevOps, security, data and machine learning, platform tasks, and project workflows.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add Jeffallan/claude-skills --skill secure-code-guardiangit clone --depth 1 https://github.com/Jeffallan/claude-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/jeffallan/claude-skills/secure-code-guardian)<a href="https://agentmods.dev/skills/jeffallan/claude-skills/secure-code-guardian"><img src="https://agentmods.dev/badge/skills/jeffallan/claude-skills/secure-code-guardian.svg" alt="Measured on agentmods" height="20"></a>- Socket pass
- Snyk pass
- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00113 | $0.01648 |
| Opus 5 | $0.00056 | $0.00824 |
| Sonnet 5 | $0.00023 | $0.00330 |
| Haiku 4.5 | $0.00011 | $0.00165 |
Grade A, and why
secure-code-guardian scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
- **Headers/CORS**: Validate with a security scanner (e.g., `curl -I`, Mozilla Observatory) that security headers are present and CORS origin allowlist is correct. How it starts
The opening of the file, as written. The whole thing — 194 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Secure Code Guardian
Core Workflow
- Threat model — Identify attack surface and threats
- Design — Plan security controls
- Implement — Write secure code with defense in depth; see code examples below
- Validate — Test security controls with explicit checkpoints (see below)
- Document — Record security decisions
Validation Checkpoints
After each implementation step, verify:
- Authentication: Test brute-force protection (lockout/rate limit triggers), session fixation resistance, token expiration, and invalid-credential error messages (must not leak user existence).
- Authorization: Verify horizontal and vertical privilege escalation paths are blocked; test with tokens belonging to different roles/users.
- Input handling: Confirm SQL injection payloads (
' OR 1=1--) are rejected; confirm XSS payloads (<script>alert(1)</script>) are escaped or rejected. - Headers/CORS: Validate with a security scanner (e.g.,
curl -I, Mozilla Observatory) that security headers are present and CORS origin allowlist is correct.
Reference Guide
Load detailed guidance based on context:
| Topic | Reference | Load When |
|---|---|---|
| OWASP | references/owasp-prevention.md |
OWASP Top 10 patterns |
| Authentication | references/authentication.md |
Password hashing, JWT |
| Input Validation | references/input-validation.md |
Zod, SQL injection |
| XSS/CSRF | references/xss-csrf.md |
XSS prevention, CSRF |
| Headers | references/security-headers.md |
Helmet, rate limiting |
Constraints
MUST DO
- Hash passwords with bcrypt/argon2 (never MD5/SHA-1/unsalted hashes)
- Use parameterized queries (never string-interpolated SQL)
- Validate and sanitize all user input before use
- Implement rate limiting on auth endpoints
- Set security headers (CSP, HSTS, X-Frame-Options)
- Log security events (failed auth, privilege escalation attempts)
- Store secrets in environment variables or secret managers (never in source code)
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 194 lines · 113 tokens per session scan A 19153a339a49
secure-code-guardian is a skill published in the GitHub repository Jeffallan/claude-skills (11,361 stars, last pushed 1mo ago), licensed MIT. It adds 113 tokens to every session and 1,648 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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