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 frank-luongt/faos-skills-marketplace --skill api-security-patternsgit clone --depth 1 https://github.com/frank-luongt/faos-skills-marketplaceWrote 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/frank-luongt/faos-skills-marketplace/api-security-patterns)<a href="https://agentmods.dev/skills/frank-luongt/faos-skills-marketplace/api-security-patterns"><img src="https://agentmods.dev/badge/skills/frank-luongt/faos-skills-marketplace/api-security-patterns/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/frank-luongt/faos-skills-marketplace/api-security-patterns"><img src="https://agentmods.dev/badge/skills/frank-luongt/faos-skills-marketplace/api-security-patterns.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00000 | $0.05219 |
| Opus 5 | $0.00000 | $0.02610 |
| Sonnet 5 | $0.00000 | $0.01044 |
| Haiku 4.5 | $0.00000 | $0.00522 |
Grade A, and why
api-security-patterns 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 12d 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 — 650 lines — stays where its author put it; the contents beside it link to each section on GitHub.
name: api-security-patterns description: Advanced API security patterns covering OWASP API Top 10, authentication, authorization, rate limiting, and gateway hardening tags: [api, security]
Advanced API Security Patterns
Overview
APIs are the primary attack surface for modern applications. Over 90% of web-enabled applications expose more attack surface through APIs than through traditional UI. This skill provides defense-in-depth patterns for API security, mapping OWASP API Security Top 10 risks to concrete prevention code.
Core principle: Every API endpoint is an entry point for attackers. Authenticate, authorize, validate, and rate-limit every request -- no exceptions.
This skill enhances the existing @owasp-api-top10 skill with implementation-level patterns for Python/FastAPI, OPA policy-as-code, Redis-based rate limiting, and GraphQL-specific defenses.
When to Use This Skill
- Designing a new API or microservice
- Conducting a security review of existing API endpoints
- Implementing authentication or authorization middleware
- Setting up rate limiting or abuse prevention
- Hardening a GraphQL or WebSocket API
- Responding to an API-related security finding or penetration test result
- Preparing for SOC 2, PCI DSS, or HIPAA compliance audits that cover API security
How It Works
Step 1: Threat Model the API Surface
Before writing security code, enumerate your attack surface:
API Threat Model Checklist:
============================
[ ] List all endpoints (including undocumented/debug endpoints)
[ ] Classify data sensitivity per endpoint (public, internal, confidential, restricted)
[ ] Identify authentication requirements per endpoint
[ ] Map authorization rules (who can access what)
[ ] Document rate limiting requirements per endpoint/consumer
[ ] Identify external dependencies and trust boundaries
[ ] Review OWASP API Top 10 against each endpoint:
API1 - Broken Object Level Authorization (BOLA)
API2 - Broken Authentication
API3 - Broken Object Property Level Authorization
API4 - Unrestricted Resource Consumption
API5 - Broken Function Level Authorization
API6 - Unrestricted Access to Sensitive Business Flows
API7 - Server-Side Request Forgery (SSRF)
API8 - Security Misconfiguration
API9 - Improper Inventory Management
API10 - Unsafe Consumption of APIs
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.
- 12d ago First seen · 650 lines · 0 tokens per session scan A 28ad760f8f6d
api-security-patterns is a skill published in the GitHub repository frank-luongt/faos-skills-marketplace (33 stars, last pushed 2mo ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 5,219 tokens. 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.
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