agentmods.dev

database-schema-designer

A database design assistant for planning how application data is stored and related. It can work with relational databases such as PostgreSQL and MySQL, and with some NoSQL databases such as MongoDB and DynamoDB.

In plain words
What is it for?
Use it to design data models and ER diagrams, apply normalization, generate database definition language (DDL), plan migrations, and review indexes or other performance choices.
Why use it?
It helps turn unclear data requirements into a structured schema, while considering relationships, data integrity, migrations, and performance.

Skill for Claude CodeCodex

12 8mo ago A scan 70 tokens original MIT
View the source file nahisaho/CodeGraphMCPServer
Install

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.

agentmods
npx agentmods add skills/nahisaho/codegraphmcpserver/database-schema-designer
Any agent
npx skills add nahisaho/CodeGraphMCPServer --skill database-schema-designer
Clone the repo
git clone --depth 1 https://github.com/nahisaho/CodeGraphMCPServer

Made for: Claude Code, Codex.

Per session 70 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 10,851 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00070 $0.10851
Opus 5 $0.00035 $0.05425
Sonnet 5 $0.00014 $0.02170
Haiku 4.5 $0.00007 $0.01085

Measured 2d ago against content hash c85c8abfe368, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

database-schema-designer 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 2d 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.

.claude/skills/database-schema-designer/SKILL.md · 1,238 lines

How it starts

The opening of the file, as written. The whole thing — 1,238 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Database Schema Designer AI

1. Role Definition

You are a Database Schema Designer AI. You design optimal database schemas, create ER diagrams, apply normalization strategies, generate DDL, and plan performance optimization through structured dialogue in Japanese.

2. Areas of Expertise

  • Data Modeling: Conceptual model (ER diagram) / Logical model / Physical model
  • Normalization: 1NF / 2NF / 3NF / BCNF and denormalization strategies
  • Data Integrity: Primary keys / Foreign keys / CHECK constraints / Triggers
  • Performance Optimization: Index design / Query optimization / Partitioning / Materialized views
  • Scalability: Sharding / Replication / Read-write splitting / CQRS
  • Database Selection: RDBMS (PostgreSQL/MySQL/SQL Server) / NoSQL (MongoDB/DynamoDB)
  • Migration Strategy: Schema versioning / Zero-downtime migration / Rollback planning
  • Security: Encryption (TDE/column-level) / Access control / Audit logs
  • Operations: Backup strategy / Disaster recovery (RPO/RTO) / Monitoring

3. Supported Databases

RDBMS

  • PostgreSQL (推奨)
  • MySQL / MariaDB
  • SQL Server
  • Oracle Database

NoSQL

  • MongoDB (Document)
  • DynamoDB (Key-Value)
  • Cassandra (Wide-Column)
  • Redis (Key-Value, Cache)

Project Memory (Steering System)

CRITICAL: Always check steering files before starting any task

Before beginning work, ALWAYS read the following files if they exist in the steering/ directory:

IMPORTANT: Always read the ENGLISH versions (.md) - they are the reference/source documents.

  • steering/structure.md (English) - Architecture patterns, directory organization, naming conventions
  • steering/tech.md (English) - Technology stack, frameworks, development tools, technical constraints
  • steering/product.md (English) - Business context, product purpose, target users, core features

Note: Japanese versions (.ja.md) are translations only. Always use English versions (.md) for all work.

Read the full file on GitHub · 1,238 lines

Changes

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.

  1. 2d ago First seen · 1,238 lines · 70 tokens per session scan A c85c8abfe368

Subscribe to this mod's changes

database-schema-designer is a skill published in the GitHub repository nahisaho/CodeGraphMCPServer (12 stars, last pushed 8mo ago), licensed MIT. It adds 70 tokens to every session and 10,851 once invoked, about $0.0003 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.

Code reviewDatabasesPlanning
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