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 LeahyCC/claude-skills --skill api-securitygit clone --depth 1 https://github.com/LeahyCC/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/leahycc/claude-skills/api-security)<a href="https://agentmods.dev/skills/leahycc/claude-skills/api-security"><img src="https://agentmods.dev/badge/skills/leahycc/claude-skills/api-security.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00044 | $0.02153 |
| Opus 5 | $0.00022 | $0.01077 |
| Sonnet 5 | $0.00009 | $0.00431 |
| Haiku 4.5 | $0.00004 | $0.00215 |
Grade A, and why
api-security 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 7d 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 — 166 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Security — OWASP API Security Top 10 (2023) for Next.js
Production-grade API security patterns for Next.js App Router. Covers every category in the OWASP API Security Top 10 (2023) with cross-references to the OWASP Web Top 10 (2021). Verified against the official OWASP specifications.
Architecture
Request → proxy.ts (auth gate) → Route Handler / Server Action
↓
Input Validation (Zod)
↓
Data Access Layer (auth + authz + DTO)
↓
Database (parameterized queries)
↓
Filtered Response (DTO, no raw records)
The Data Access Layer (DAL) is the central security architecture recommended by Next.js. All database access, authorization checks, and response filtering happen in one server-only module — never in components or actions directly.
Quick Reference
| Resource | OWASP API | OWASP Web | What It Covers |
|---|---|---|---|
| Access Control | API1, API5 | A01 | BOLA/IDOR, function-level auth, ownership checks |
| Authentication | API2 | A07, A02 | Session management, JWT, Clerk/Auth0, proxy.ts |
| Input Validation | API3, API8 | A03 | Zod schemas, SQL injection, XSS, Server Action validation |
| Rate Limiting | API4 | A04 | Per-endpoint limits, cost attacks, Upstash patterns |
| Security Headers | API8 | A05 | CSP, HSTS, CORS, Permissions-Policy, next.config |
| Data Exposure | API3, API6 | A04 | DAL pattern, DTOs, error sanitization, response filtering |
| Supply Chain | API9, API10 | A06, A08 | Dependencies, env vars, CI/CD, third-party APIs |
| SSRF & Logging | API7 | A09, A10 | URL validation, fetch safety, secure logging, audit trails |
What ships with it
9 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.
- 7d ago First seen · 166 lines · 44 tokens per session scan A 5ee636274e57
api-security is a skill published in the GitHub repository LeahyCC/claude-skills (3 stars, last pushed 1mo ago), licensed MIT. It adds 44 tokens to every session and 2,153 once invoked, about $0.0002 per session on Opus 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 2026-08-31.
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