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 sethdford/claude-skills --skill data-model-designgit clone --depth 1 https://github.com/sethdford/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/sethdford/claude-skills/data-model-design)<a href="https://agentmods.dev/skills/sethdford/claude-skills/data-model-design"><img src="https://agentmods.dev/badge/skills/sethdford/claude-skills/data-model-design/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/sethdford/claude-skills/data-model-design"><img src="https://agentmods.dev/badge/skills/sethdford/claude-skills/data-model-design.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 | $0.00030 | $0.00338 |
| Opus 5 | $0.00015 | $0.00169 |
| Sonnet 5 | $0.00006 | $0.00068 |
| Haiku 4.5 | $0.00003 | $0.00034 |
Grade A, and why
data-model-design 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.
What it actually says
Data Model Design
Design data models that correctly represent business domains and support required queries efficiently.
Context
You are modeling a business domain in a database. The data model must reflect business semantics and perform well.
Domain Context
Based on relational theory and domain-driven design:
- Entities: Things with identity (User, Order)
- Attributes: Properties of entities (name, email)
- Relationships: How entities connect (User has many Orders)
- Normalization: Reduce redundancy; improves write performance
- Denormalization: Intentionally duplicate data; improves read performance
Instructions
- Identify Entities: What are the main concepts? List with primary key.
- Identify Attributes: For each entity, list properties.
- Define Relationships: One-to-one, one-to-many, many-to-many.
- Normalize: Remove update anomalies through normal forms.
- Denormalize Strategically: Add calculated columns or tables for read performance.
Anti-Patterns
- Premature Normalization: Third-normal-form everywhere. Result: slow queries. Guard: Design for reads; denormalize if needed.
- Flat Tables: No normalization; entity data scattered. Result: update anomalies. Guard: At least second-normal-form.
Further Reading
- Relational Database Design — normalization fundamentals
- Domain-Driven Design — modeling business domains
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 · 41 lines · 30 tokens per session scan A c52365ee80ed
data-model-design is a skill published in the GitHub repository sethdford/claude-skills (40 stars, last pushed 6mo ago), licensed MIT. It adds 30 tokens to every session and 338 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 2026-08-30.
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