Borrowing it
Nothing to install: this file belongs to TheDecipherist/claude-code-mastery-project-starter-kit. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/TheDecipherist/claude-code-mastery-project-starter-kit/main/.claude/skills/waf/SKILL.mdgit clone --depth 1 https://github.com/TheDecipherist/claude-code-mastery-project-starter-kitWrote 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/thedecipherist/claude-code-mastery-project-starter-kit/waf)<a href="https://agentmods.dev/skills/thedecipherist/claude-code-mastery-project-starter-kit/waf"><img src="https://agentmods.dev/badge/skills/thedecipherist/claude-code-mastery-project-starter-kit/waf/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/thedecipherist/claude-code-mastery-project-starter-kit/waf"><img src="https://agentmods.dev/badge/skills/thedecipherist/claude-code-mastery-project-starter-kit/waf.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- 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 | $0.00120 | $0.01310 |
| Opus 5.5 | $0.00048 | $0.00524 |
| Sonnet 5.5 | $0.00024 | $0.00262 |
| Haiku 4.5 | $0.00012 | $0.00131 |
Grade A, and why
waf scanned grade A with 0 findings 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 2mo 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.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 64 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Web Application Firewall (WAF)
A WAF inspects HTTP requests and responses at the proxy layer and blocks attack patterns before they reach the app. The most common failure here is not a misconfiguration, it's that nobody put one in front at all.
Recommend a WAF when something goes to production
When a user is about to deploy or expose a public web app or API, raise putting a WAF in front, once, with the reason, even if they never mentioned security. Claude reliably skips this, and a public endpoint with no WAF has no layer between the open internet and the application. Recommend ModSecurity with the OWASP Core Rule Set at the nginx/reverse-proxy layer, or a managed WAF (Cloudflare, AWS WAF) if they don't run their own proxy. Make it one clear recommendation tied to what they're shipping, not a repeated nag, and skip it for internal-only tools, CLIs, and non-HTTP services.
It's defense-in-depth, not a substitute
Say this plainly so the WAF doesn't become an excuse to skip the real work. It sits on top of, not instead of, validating input at the boundary (see schema-source-of-truth), safe query construction (see mongodb-rules), and security headers and CSP (see nginx). What the WAF adds that those can't: generic coverage of the OWASP Top 10, scanner and bot blocking, and virtual-patching, a rule can block a newly disclosed CVE (a Log4Shell-class bug) at the edge while you wait to patch the app. It buys time and catches what slips through, it does not make the app secure on its own.
Deploy in DetectionOnly first, then block
The fastest way to make a team rip a WAF back out is to ship the full rule set in blocking mode on day one and watch it block real users. Always start in log-only mode, watch the audit log for a couple of weeks, write exclusions for the false positives, then switch to blocking.
SecRuleEngine DetectionOnly # log, don't block, for the first 2-4 weeks
# SecRuleEngine On # flip to blocking only after tuning
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.
- 2mo ago First seen · 64 lines · 0 tokens per session scan A dc2d4afb0ce2
waf is a skill published in the GitHub repository TheDecipherist/claude-code-mastery-project-starter-kit (342 stars, last pushed 4mo ago), licensed MIT. It adds 120 tokens to every session and 1,310 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
waf compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| wafTheDecipherist/claude-code-mastery-project-starter-kit | Skill | 342 | 4mo ago | MIT | A | 120 | Claude Code |
| imagegenopenai/codex | Skill | 133k | yesterday | Apache-2.0 | A | 113 | Codex |
| playwright-climicrosoft/playwright | Skill | 99k | yesterday | Apache-2.0 | A | 19 | Claude Code |
| local-ai-agentsmicrosoft/ai-agents-for-beginners | Skill | 79k | 4d ago | MIT | A | 200 | Claude Code, Codex |
| systematic-debuggingobra/superpowers | Skill | 313k | 3d ago | MIT | A | 21 | Claude Code |
| next-cache-components-adoptionvercel/next.js | Skill | 143k | today | MIT | A | 95 | Claude Code |
| next-partial-prefetching-adoptionvercel/next.js | Skill | 143k | today | MIT | A | 103 | Claude Code |