schema-analyzer

schema-analyzer is a skill for Claude Code, Codex from JansenAnalytics/claudex. It costs 29 tokens per session (355 once invoked), scanned A, original, MIT.

A database-schema analysis tool that maps tables and relationships, checks design quality, and suggests indexes. A schema is the structure that defines how a database stores related data.

In plain words
What is it for?
Use it to generate entity-relationship diagrams, audit schemas, find normalization issues, detect missing foreign keys, and review indexes.
Why use it?
It helps reveal missing relationships, inefficient lookups, and structural problems before they cause maintenance or performance issues.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is python3 scripts/schema-erd.py --db myapp.db --type sqlite --format mermaid.

Good fit Use it to generate entity-relationship diagrams, audit schemas, find normalization issues, detect missing foreign keys, and review indexes.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/JansenAnalytics/claudex
agentmods
npx agentmods add skills/jansenanalytics/claudex/schema-analyzer

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for schema-analyzer

README.md
[![agentmods](https://agentmods.dev/badge/skills/jansenanalytics/claudex/schema-analyzer.svg)](https://agentmods.dev/skills/jansenanalytics/claudex/schema-analyzer)
Your own site
<a href="https://agentmods.dev/skills/jansenanalytics/claudex/schema-analyzer"><img src="https://agentmods.dev/badge/skills/jansenanalytics/claudex/schema-analyzer.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 355 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00029 $0.00355
Opus 5 $0.00015 $0.00178
Sonnet 5 $0.00006 $0.00071
Haiku 4.5 $0.00003 $0.00036

Measured 4d ago against content hash e4a87899f294, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

schema-analyzer 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 4d 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.

skills/schema-analyzer/SKILL.md · 57 lines

What it actually says

schema-analyzer

Analyze database schemas: generate ERD diagrams, detect normalization issues, suggest indexes, find missing foreign keys, audit schema quality.

When to Use

  • Understanding a database structure
  • Generating entity-relationship diagrams
  • Optimizing schema design
  • Finding denormalization issues
  • Auditing database quality

Scripts

schema-erd.py

Generate ERD (Mermaid diagram) from a database.

python3 scripts/schema-erd.py --db myapp.db --type sqlite --format mermaid
python3 scripts/schema-erd.py --db myapp.db --type sqlite --format text
python3 scripts/schema-erd.py --db myapp.db --type sqlite --format json

schema-audit.py

Audit schema quality and find issues.

python3 scripts/schema-audit.py --db myapp.db --type sqlite

Reports: missing PKs, missing indexes on FKs, naming inconsistencies, missing timestamps, nullable issues.

index-advisor.py

Suggest optimal indexes.

python3 scripts/index-advisor.py --db myapp.db --type sqlite

Reports: existing indexes, suggested new indexes, foreign key columns without indexes.

References

  • normalization-guide.md — 1NF through 3NF with examples
  • indexing-guide.md — Index types, composite indexes, when indexes hurt
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. 4d ago First seen · 57 lines · 29 tokens per session scan A e4a87899f294

Subscribe to this mod's changes

schema-analyzer is a skill published in the GitHub repository JansenAnalytics/claudex (5 stars, last pushed 2mo ago), licensed MIT. It adds 29 tokens to every session and 355 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 2026-09-03.