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 svngoku/coding-agents-skills --skill database-designgit clone --depth 1 https://github.com/svngoku/coding-agents-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/svngoku/coding-agents-skills/database-design)<a href="https://agentmods.dev/skills/svngoku/coding-agents-skills/database-design"><img src="https://agentmods.dev/badge/skills/svngoku/coding-agents-skills/database-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/svngoku/coding-agents-skills/database-design"><img src="https://agentmods.dev/badge/skills/svngoku/coding-agents-skills/database-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 | $0.00163 | $0.04202 |
| Opus 5.5 | $0.00065 | $0.01681 |
| Sonnet 5.5 | $0.00033 | $0.00840 |
| Haiku 4.5 | $0.00016 | $0.00420 |
Grade A, and why
database-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 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.
How it starts
The opening of the file, as written. The whole thing — 299 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Database Design
Database design turns a domain into a schema that stays fast, correct, and easy to evolve for years. This skill covers the full pipeline — requirements analysis, entity modeling, normalization, keys, constraints, indexes, and safe migrations — plus deciding when a document, wide-column, or graph store beats a relational database.
Quick Reference
| Topic | Reference |
|---|---|
| Normalization worked examples, natural vs surrogate keys, UUID vs bigint | normalization-and-keys.md |
| B-tree internals, composite/covering/partial indexes, reading EXPLAIN | indexing-and-query-tuning.md |
| Migration tools (Alembic, Prisma, Flyway), expand-contract, backfilling | migrations-zero-downtime.md |
Core Workflow
Work through these steps in order — each informs the next, and skipping requirements analysis is the most common source of bad schemas.
- Gather requirements. List entities, attributes, and relationships. Note cardinalities and whether each read is CRUD (single-row) or reporting (aggregate). Ask about scale, growth, retention, and compliance (e.g. GDPR erasure).
- Model entities and relationships. Draw an ER sketch. Normalize to 3NF by default; denormalize only later, with a measured reason.
- Choose keys. Prefer surrogate
BIGINT IDENTITYprimary keys unless a natural key is genuinely stable. Decide UUID vs bigint now — changing it later is painful. - Add constraints. NOT NULL, UNIQUE, CHECK, defaults, and foreign keys belong in the database, not just in the ORM.
- Design indexes. Start with the indexes backing PK/FK/UNIQUE constraints, then add query-driven indexes for the hot paths found in step 1.
- Validate with EXPLAIN. Run
EXPLAIN (ANALYZE, BUFFERS)against realistic data. Fix the plan, not the schema, before considering denormalization. - Plan migrations. Versioned migrations in code; expand-contract for anything touching a live table. Never hand-edit production.
What ships with it
8 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.
- 1mo ago First seen · 299 lines · 163 tokens per session scan A ae57142b82ea
database-design is a skill published in the GitHub repository svngoku/coding-agents-skills (12 stars, last pushed 3d ago), licensed MIT. It adds 163 tokens to every session and 4,202 once invoked, about $0.0007 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 2026-08-31.
Other skills, from other repositories
postgresql-development-cloudbase
Use when building, debugging, or evaluating CloudBase PostgreSQL / CloudBase PG / PG mode apps, including Postgres schema setup, queryPgDatabase/managePgDatabase, JS SDK v3 app.rdb() CRUD/RPC, PG HTTP API fallback, RLS-style permissions, username-password auth, and Web CMS/admin CRUD flows backed by CloudBase PG.
cloudbase-document-database-web-sdk
Use CloudBase document database Web SDK only for confirmed NoSQL collection work. Query, create, update, and delete document data; if the task mentions PostgreSQL / CloudBase PG / app.rdb(), route to postgresql-development instead.
minimal-web-baas-demo
A quick setup path for a small CloudBase web application with a database. CloudBase is a backend service that provides hosting and data storage, while CRUD means creating, reading, updating, and deleting records.
data-model-creation
Sibling CloudBase skills ship beside this skill. Use local relative paths such as ../auth-tool-cloudbase/SKILL.md.
relational-database-mcp-cloudbase
Sibling CloudBase skills ship beside this skill. Use local relative paths such as ../auth-tool-cloudbase/SKILL.md.
relational-database-web-cloudbase
Sibling CloudBase skills ship beside this skill. Use local relative paths such as ../auth-tool-cloudbase/SKILL.md.