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 martinholovsky/claude-skills-generator --skill database-designgit clone --depth 1 https://github.com/martinholovsky/claude-skills-generatorWrote 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/martinholovsky/claude-skills-generator/database-design)<a href="https://agentmods.dev/skills/martinholovsky/claude-skills-generator/database-design"><img src="https://agentmods.dev/badge/skills/martinholovsky/claude-skills-generator/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/martinholovsky/claude-skills-generator/database-design"><img src="https://agentmods.dev/badge/skills/martinholovsky/claude-skills-generator/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 | $0.00028 | $0.03644 |
| Opus 5 | $0.00014 | $0.01822 |
| Sonnet 5 | $0.00006 | $0.00729 |
| Haiku 4.5 | $0.00003 | $0.00364 |
Grade A, and why
Database Design Expert 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.
How it starts
The opening of the file, as written. The whole thing — 488 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Database Design Expert
0. Mandatory Reading Protocol
CRITICAL: Before implementing ANY database schema, you MUST read the relevant reference files:
Trigger Conditions for Reference Files
Read references/advanced-patterns.md WHEN:
- Designing schemas for new features
- Implementing complex relationships (many-to-many, polymorphic)
- Setting up inheritance patterns
- Designing for high-performance queries
Read references/security-examples.md WHEN:
- Storing sensitive user data
- Designing audit trails
- Implementing access control at database level
- Handling PII or financial data
1. Overview
Risk Level: MEDIUM
Justification: Database schema design impacts data integrity, query performance, and application security. Poor design can lead to data corruption, performance bottlenecks, and difficulty in maintaining data consistency. Schema changes in production require careful migration planning.
You are an expert in database schema design, specializing in:
- Normalization with appropriate denormalization for performance
- Indexing strategies for query optimization
- Full-Text Search (FTS5) schema design
- Constraint design for data integrity
- Migration-friendly schemas that evolve safely
Core Principles
- TDD First - Write tests for schema and queries before implementation
- Performance Aware - Design for query patterns, optimize indexes, profile regularly
- Normalize then denormalize - Start with 3NF, denormalize based on measured needs
- Constraint everything - Use database constraints as the last line of defense
- Migration safety - All schema changes must be reversible and tested
Primary Use Cases
- Desktop application data modeling
- Local-first application architecture
- Efficient search and retrieval patterns
- Audit and history tracking
- Configuration and settings storage
2. Core Responsibilities
2.1 Data Integrity Principles
- Normalize to eliminate redundancy - Then denormalize strategically for performance
- Use appropriate constraints - Primary keys, foreign keys, unique, check constraints
- Design for referential integrity - Foreign keys with appropriate cascade rules
- Plan for schema evolution - Design migrations that preserve data
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 · 488 lines · 28 tokens per session scan A 69822487c240
Database Design Expert is a skill published in the GitHub repository martinholovsky/claude-skills-generator (45 stars, last pushed 9mo ago), licensed Unlicense. It adds 28 tokens to every session and 3,644 once invoked, about $0.0001 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.
Other skills, from other repositories
database-engineer
!cat skills/shared/protocols/ux-protocol.md 2>/dev/null || true !cat skills/shared/protocols/input-validation.md 2>/dev/null || true !cat skills/shared/protocols/tool-efficiency.md 2>/dev/null || true !cat .production-grade.yaml 2>/dev/null || echo "No config — using defaults" !cat .forgewright/codebase-context.md…
relational-database-design
Designs or reviews a relational database schema for a given domain. Covers table structure, normalization, indexes, constraints, and migration strategy. Invoked when the user asks to design a schema, review a database structure, or optimize a data model.
sql-agent
Write, optimize, and explain SQL queries. Use when user needs to write a query, debug slow SQL, understand a query plan, or design a schema.
database-design-patterns
Database schema design patterns and optimization strategies for relational and NoSQL databases. Use when designing database schemas, optimizing query performance, or implementing data persistence layers at scale.
Schema Design
Principles for designing database schemas that stay additive, constraint-driven, and safe to evolve as the application grows.
Database Performance Testing
Database performance testing including query optimization, index analysis, connection pooling, slow query detection, and N+1 query prevention.