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 HoangNguyen0403/agent-skills-standard --skill database-schema-designgit clone --depth 1 https://github.com/HoangNguyen0403/agent-skills-standardWrote 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/hoangnguyen0403/agent-skills-standard/database-schema-design)<a href="https://agentmods.dev/skills/hoangnguyen0403/agent-skills-standard/database-schema-design"><img src="https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/database-schema-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/hoangnguyen0403/agent-skills-standard/database-schema-design"><img src="https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/database-schema-design.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00331 |
| Opus 5 | $0.00018 | $0.00166 |
| Sonnet 5 | $0.00007 | $0.00066 |
| Haiku 4.5 | $0.00004 | $0.00033 |
Grade A, and why
database-schema-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
Database Schema Design
Priority: P0 (CRITICAL)
Start from reads, writes, and ownership. Schema follows access patterns, not vice versa.
Rules
- Model one business concept per table/collection boundary.
- Choose embed vs reference or normalize vs denormalize from cardinality, update frequency, and read locality.
- Encode uniqueness, nullability, and foreign-key or ownership rules explicitly.
- Prefer additive evolution over destructive redesigns.
Verify
- Hot reads are supported without avoidable joins or fan-out.
- Cardinality and lifecycle were written down for major relationships.
- Constraints or validation rules exist for business invariants.
- IDs, timestamps, and soft-delete semantics are consistent.
Anti-Patterns
- No schema from ORM defaults: model business access patterns first.
- No many-to-many without owner rules: define source of truth and cleanup behavior.
- No nullable drift: nullable fields need lifecycle meaning.
References
What ships with it
2 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.
- 9d ago First seen · 47 lines · 36 tokens per session scan A 399d00c5fc35
database-schema-design is a skill published in the GitHub repository HoangNguyen0403/agent-skills-standard (565 stars, last pushed 3d ago), licensed MIT. It adds 36 tokens to every session and 331 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 2026-09-03.
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supabase
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sql
SELECT columns FROM table WHERE condition ORDER BY column LIMIT n.