Borrowing it
Nothing to install: this file belongs to KbWen/agentic-os. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/KbWen/agentic-os/main/.agents/skills/database-design/SKILL.mdgit clone --depth 1 https://github.com/KbWen/agentic-osWrote 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/kbwen/agentic-os/database-design)<a href="https://agentmods.dev/skills/kbwen/agentic-os/database-design"><img src="https://agentmods.dev/badge/skills/kbwen/agentic-os/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/kbwen/agentic-os/database-design"><img src="https://agentmods.dev/badge/skills/kbwen/agentic-os/database-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 | $0.00013 | $0.01135 |
| Opus 5.5 | $0.00005 | $0.00454 |
| Sonnet 5.5 | $0.00003 | $0.00227 |
| Haiku 4.5 | $0.00001 | $0.00113 |
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 14d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- database-design — 100% identical, 2 lines differ
How it starts
The opening of the file, as written. The whole thing — 108 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Database Design
When to Apply
- Classification: feature (if new tables/columns), architecture-change (schema redesign), hotfix (data-related bug)
- Phase: /plan (schema design), /implement (migration creation), /review (schema review), /test (data integrity)
- Trigger: Task involves creating tables, modifying schema, writing migrations, or changing data access patterns
Conventions
Customize after /app-init: Replace these generic conventions with your project's ADR and ORM-specific patterns.
Table Design
- Every table MUST have:
id(primary key),created_at,updated_at - Use UUIDs or auto-increment IDs consistently (per ADR decision)
- Soft delete: add
deleted_atcolumn if ADR specifies soft delete - Table names: plural, snake_case (e.g.,
users,order_items) - Column names: snake_case (e.g.,
first_name,is_active)
Relationship Patterns
| Relationship | Implementation | Example |
|---|---|---|
| One-to-Many | Foreign key on "many" side | orders.user_id → users.id |
| Many-to-Many | Junction table | user_roles (user_id, role_id) |
| One-to-One | Foreign key + unique constraint | user_profiles.user_id (UNIQUE) → users.id |
| Self-referencing | Foreign key to same table | categories.parent_id → categories.id |
Index Strategy
- Every foreign key column MUST have an index
- Columns used in WHERE clauses frequently → add index
- Composite indexes: put the most selective column first
- Unique constraints for business uniqueness rules (email, username, etc.)
- DO NOT over-index: every index slows writes
Migration Rules
- One migration per logical change (don't mix table creation with data backfill)
- Migrations MUST be reversible: every
upmust have a correspondingdown - Never modify a shipped migration: create a new migration instead
- Data migrations separate from schema migrations: schema first, data second
- Test rollback: after writing migration, verify
downworks cleanly
What ships with it
1 file 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.
- 14d ago Changed 89110bfff468
- 1mo ago First seen · 108 lines · 13 tokens per session scan A 31eb0d403f37
database-design is a skill published in the GitHub repository KbWen/agentic-os (220 stars, last pushed yesterday), licensed MIT. It adds 13 tokens to every session and 1,135 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 2026-08-30.
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