seed-data

seed-data is a skill for Claude Code, Codex from JansenAnalytics/claudex. It costs 26 tokens per session (562 once invoked), scanned A, original, MIT.

A data generator that creates realistic sample records from a database schema, including users, products, orders, time series, and financial data.

In plain words
What is it for?
Use it to populate development databases, create test fixtures and demo environments, and export sample data as SQL, JSON, or CSV.
Why use it?
It gives developers usable data for testing and interface work without manually filling databases with placeholder records.

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/seed-gen.py --schema schema.json --format sql --output seed.sql.

Good fit Use it to populate development databases, create test fixtures and demo environments, and export sample data as SQL, JSON, or CSV.

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/seed-data

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 seed-data

README.md
[![agentmods](https://agentmods.dev/badge/skills/jansenanalytics/claudex/seed-data.svg)](https://agentmods.dev/skills/jansenanalytics/claudex/seed-data)
Your own site
<a href="https://agentmods.dev/skills/jansenanalytics/claudex/seed-data"><img src="https://agentmods.dev/badge/skills/jansenanalytics/claudex/seed-data.svg" alt="Measured on agentmods" height="20"></a>
Per session 26 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 562 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 $0.00026 $0.00562
Opus 5 $0.00013 $0.00281
Sonnet 5 $0.00005 $0.00112
Haiku 4.5 $0.00003 $0.00056

Measured 4d ago against content hash 63708a42ef1f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

seed-data 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/seed-data/SKILL.md · 78 lines

What it actually says

seed-data

Generate realistic test and seed data for any database schema: users, products, orders, time series, financial data.

When to Use

  • Populating databases for testing
  • Creating demo data
  • Generating fixtures for development
  • Seeding development environments
  • Creating realistic datasets for UI development

Scripts

seed-gen.py

Universal seed data generator with zero dependencies.

python3 scripts/seed-gen.py --schema schema.json --format sql --output seed.sql
python3 scripts/seed-gen.py --schema schema.json --format json
python3 scripts/seed-gen.py --schema schema.json --format csv --output data.csv

Schema format:

{
  "tables": [
    {
      "name": "users",
      "count": 100,
      "columns": [
        { "name": "id", "type": "serial" },
        { "name": "email", "type": "email" },
        { "name": "name", "type": "name" },
        { "name": "created_at", "type": "datetime", "range": ["2024-01-01", "2024-12-31"] }
      ]
    }
  ]
}

Supported types: serial, uuid, name, email, phone, address, company, text, integer, float, boolean, datetime, date, choice, foreign_key

timeseries-gen.py

Generate realistic time series data.

python3 scripts/timeseries-gen.py --type stock --start 2024-01-01 --end 2024-12-31 --interval 1h
python3 scripts/timeseries-gen.py --type temperature --start 2024-01-01 --end 2024-12-31 --interval 1d
python3 scripts/timeseries-gen.py --type pageviews --interval 1h --output views.csv

Types: stock, temperature, pageviews, sensor

schema-to-seed.sh

Generate seed schema JSON from existing database.

bash scripts/schema-to-seed.sh --db myapp.db --type sqlite --output schema.json
bash scripts/schema-to-seed.sh --db "postgresql://user:pass@host/db" --type postgres --output schema.json

References

  • data-patterns.md — Realistic data patterns and distributions
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 · 78 lines · 26 tokens per session scan A 63708a42ef1f

Subscribe to this mod's changes

seed-data is a skill published in the GitHub repository JansenAnalytics/claudex (5 stars, last pushed 2mo ago), licensed MIT. It adds 26 tokens to every session and 562 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.

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