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 rootcastleco/rei-skills --skill api-security-best-practicesgit clone --depth 1 https://github.com/rootcastleco/rei-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/rootcastleco/rei-skills/api-security-best-practices)<a href="https://agentmods.dev/skills/rootcastleco/rei-skills/api-security-best-practices"><img src="https://agentmods.dev/badge/skills/rootcastleco/rei-skills/api-security-best-practices/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/rootcastleco/rei-skills/api-security-best-practices"><img src="https://agentmods.dev/badge/skills/rootcastleco/rei-skills/api-security-best-practices.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 | $0.00029 | $0.05975 |
| Opus 5 | $0.00015 | $0.02988 |
| Sonnet 5 | $0.00006 | $0.01195 |
| Haiku 4.5 | $0.00003 | $0.00598 |
Grade A, and why
api-security-best-practices 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 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.
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.
The source is not reproduced here
A licence we could not identify
The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.
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 · 918 lines · 29 tokens per session scan A 58cfae9e4898
api-security-best-practices is a skill published in the GitHub repository rootcastleco/rei-skills (6 stars, last pushed today), with no licence file. It adds 29 tokens to every session and 5,975 once invoked, about $0.0001 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.
Other skills, from other repositories
mcp-builder
Guide for creating high-quality MCP (Model Context Protocol) servers that enable LLMs to interact with external services through well-designed tools. Use when building MCP servers to integrate external APIs or services, whether in Python (FastMCP) or Node/TypeScript (MCP SDK).
fullstack-developer
Modern web development expertise covering React, Node.js, TypeScript, databases, and full-stack architecture patterns.
ai-sdk
Answer questions about the Vercel AI SDK and help build AI-powered features. Use when developers ask about AI SDK functions like generateText, streamText, ToolLoopAgent, embed, or tools, want to build AI agents, chatbots, RAG systems, or text generation features, have questions about AI providers (OpenAI, Anthropic…
chat-sdk
Build multi-platform chat bots with Chat SDK (chat npm package). Use when developers want to (1) Build a Slack, Teams, Google Chat, Discord, GitHub, or Linear bot, (2) Use the Chat SDK to handle mentions, messages, reactions, slash commands, cards, modals, or streaming, (3) Set up webhook handlers for chat platforms…
azure-communication-services
Expert knowledge for Azure Communication Services development including troubleshooting, best practices, decision making, architecture & design patterns, limits & quotas, security, configuration, integrations & coding patterns, and deployment. Use when building ACS calling/chat apps, SMS/email senders, Teams interop…
amazon-alexa-v2
AMAZON ALEXA — Voz Inteligente com Claude workflow skill. Use this skill when the user needs Integracao completa com Amazon Alexa para criar skills de voz inteligentes, transformar Alexa em assistente com Claude como cerebro (projeto Auri) e integrar com AWS ecosystem (Lambda, DynamoDB, Polly, Transcribe, Lex, Smart…