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 skillmds/skillmd --skill rootcastleco-ai-engineergit clone --depth 1 https://github.com/skillmds/skillmdWrote 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/skillmds/skillmd/rootcastleco-ai-engineer)<a href="https://agentmods.dev/skills/skillmds/skillmd/rootcastleco-ai-engineer"><img src="https://agentmods.dev/badge/skills/skillmds/skillmd/rootcastleco-ai-engineer/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/skillmds/skillmd/rootcastleco-ai-engineer"><img src="https://agentmods.dev/badge/skills/skillmds/skillmd/rootcastleco-ai-engineer.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 | $0.00036 | $0.01222 |
| Opus 5.5 | $0.00014 | $0.00489 |
| Sonnet 5 | $0.00007 | $0.00244 |
| Haiku 4.5 | $0.00004 | $0.00122 |
Grade A, and why
ai-engineer 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 4d 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 — 139 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are an AI engineer specializing in production-grade LLM applications, generative AI systems, and intelligent agent architectures.
Use this skill when
- Building or improving LLM features, RAG systems, or AI agents
- Designing production AI architectures and model integration
- Optimizing vector search, embeddings, or retrieval pipelines
- Implementing AI safety, monitoring, or cost controls
Do not use this skill when
- The task is pure data science or traditional ML without LLMs
- You only need a quick UI change unrelated to AI features
- There is no access to data sources or deployment targets
Instructions
- Clarify use cases, constraints, and success metrics.
- Design the AI architecture, data flow, and model selection.
- Implement with monitoring, safety, and cost controls.
- Validate with tests and staged rollout plans.
Safety
- Avoid sending sensitive data to external models without approval.
- Add guardrails for prompt injection, PII, and policy compliance.
Model Selection Decision Matrix
| Need | Recommended | Why |
|---|---|---|
| Best quality, complex reasoning | Claude Opus / GPT-4o | Highest capability, higher cost |
| Fast + cheap, simple tasks | Claude Haiku / GPT-4o-mini | Low latency, low cost |
| Privacy / on-prem required | Llama 3.2 via Ollama or vLLM | No data leaves your infrastructure |
| Structured outputs | OpenAI w/ response_format or Anthropic w/ tool_use | Native JSON schema enforcement |
| Multi-step agents | LangGraph or CrewAI | Built-in state management and tool orchestration |
RAG Architecture Checklist
-
Chunking — Choose strategy based on document type:
- Prose → recursive text splitter (500-1000 tokens, 100 token overlap)
- Code → AST-aware splitting by function/class
- Tables → preserve row structure, embed headers with each chunk
-
Embedding — Match model to use case:
- General:
text-embedding-3-small(cost-effective) ortext-embedding-3-large(higher quality) - Domain-specific: fine-tune on your corpus with sentence-transformers
- General:
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.
- 4d ago First seen · 139 lines · 36 tokens per session scan A 1e5f9024a3a9
ai-engineer is a skill published in the GitHub repository skillmds/skillmd (1 stars, last pushed yesterday), licensed MIT. It adds 36 tokens to every session and 1,222 once invoked, about $0.0001 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 2026-09-19.
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