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.
git clone --depth 1 https://github.com/j4flmao/agent-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/rules/j4flmao/agent-skills/database-design-standards)<a href="https://agentmods.dev/rules/j4flmao/agent-skills/database-design-standards"><img src="https://agentmods.dev/badge/rules/j4flmao/agent-skills/database-design-standards/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/rules/j4flmao/agent-skills/database-design-standards"><img src="https://agentmods.dev/badge/rules/j4flmao/agent-skills/database-design-standards.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 | $0.00021 | $0.00377 |
| Opus 5.5 | $0.00008 | $0.00151 |
| Sonnet 5.5 | $0.00004 | $0.00075 |
| Haiku 4.5 | $0.00002 | $0.00038 |
Grade A, and why
database-design-standards 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 1mo 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 Design Standards
Cursor/AI MUST follow these rules when writing SQL, Prisma schemas, TypeORM entities, or Database migrations.
1. Primary Key Generation (The UUIDv4 Ban)
- Rule: NEVER use
UUIDv4(fully random UUIDs) as a Primary Key in a relational database (PostgreSQL, MySQL). - Why: B-Tree storage engines suffer massive fragmentation (Page Splits) when inserting non-sequential random data.
- Action: Use sequential IDs (e.g.,
BIGSERIAL),UUIDv7(time-ordered),ULID, or Snowflake IDs.
2. No Soft Deletes via Booleans
- Rule: Avoid
is_deleted = booleanfor soft deletes in high-scale tables. - Action: Use
deleted_at = TIMESTAMP. It provides audibility (when was it deleted) and can still be easily filtered (WHERE deleted_at IS NULL).
3. Rely on the Database for Integrity
- Rule: Never enforce data integrity solely in application code (e.g., checking if a username exists before inserting).
- Action: Use
UNIQUEconstraints,FOREIGN KEYconstraints, andCHECKconstraints (e.g.,CHECK (price > 0)). Let the Database enforce ACID guarantees.
4. N+1 Query Prevention
- Rule: When generating ORM code or raw SQL to fetch a list of entities and their children, you MUST proactively implement batching (e.g.,
DataLoader) or SQLJOINs to prevent N+1 query loops.
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.
- 1mo ago First seen · 25 lines · 21 tokens per session scan A 62a63c0d09da
database-design-standards is a cursor rule published in the GitHub repository j4flmao/agent-skills (33 stars, last pushed 10d ago), licensed MIT. It adds 21 tokens to every session and 377 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 2026-09-05.
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