seed-data-and-fixtures

seed-data-and-fixtures is a skill for Claude Code from aneja5/forge-skills. It costs 56 tokens per session (1,617 once invoked), scanned A, original, MIT.

A workflow for creating realistic demo data, test fixtures, seed scripts, and reusable factory functions. It includes edge cases and can be run repeatedly without creating duplicate records.

In plain words
What is it for?
Use it to populate development environments, prepare sales-demo data, reproduce bugs with specific records, and share consistent fixtures across tests.
Why use it?
It removes placeholder data, inconsistent test setups, missing edge cases, and seed scripts that fail when run more than once.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the forge-skills plugin — 42 skills, 36 commands, 1 hook shipped together

Good fit Use it to populate development environments, prepare sales-demo data, reproduce bugs with specific records, and share consistent fixtures across tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/aneja5/forge-skills/seed-data-and-fixtures
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.

Any agent
npx skills add aneja5/forge-skills --skill seed-data-and-fixtures
Clone the repo
git clone --depth 1 https://github.com/aneja5/forge-skills

Made for: Claude Code.

Or install forge-skills, the plugin that ships this one along with the rest of its 42 skills, 36 commands, 1 hook.

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-and-fixtures

README.md
[![agentmods](https://agentmods.dev/badge/skills/aneja5/forge-skills/seed-data-and-fixtures/github.svg)](https://agentmods.dev/skills/aneja5/forge-skills/seed-data-and-fixtures)
Your own site
<a href="https://agentmods.dev/skills/aneja5/forge-skills/seed-data-and-fixtures"><img src="https://agentmods.dev/badge/skills/aneja5/forge-skills/seed-data-and-fixtures/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.

agentmods 80×15 button for seed-data-and-fixtures

Your own site · 80×15
<a href="https://agentmods.dev/skills/aneja5/forge-skills/seed-data-and-fixtures"><img src="https://agentmods.dev/badge/skills/aneja5/forge-skills/seed-data-and-fixtures.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,617 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 $0.00056 $0.01617
Opus 5 $0.00028 $0.00809
Sonnet 5 $0.00011 $0.00323
Haiku 4.5 $0.00006 $0.00162

Measured 9d ago against content hash 003cf847bdf2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

seed-data-and-fixtures 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.

skills/seed-data-and-fixtures/SKILL.md · 121 lines

How it starts

The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Seed Data and Fixtures

Overview

Produce realistic data for demos, dev environments, and tests — before lorem ipsum makes it to a screenshot. Output is .forge/seed-data.md (the entity inventory, distributions, demo scenarios, and the factory contract) plus the seed scripts themselves. Seeds must be realistic (real-feeling names, plausible timestamps, domain-appropriate content), comprehensive (edge cases included), reproducible (seeded RNG), and idempotent (re-runnable without dupes). Consumed by incremental-implementation (factories for tests), demo-narrative (demo scenes), and testing-strategy (golden-test fixtures).

When to Use

  • A new dev environment is being set up and there's no seed data
  • A demo is coming up and the screenshots have lorem ipsum or "Test User"
  • Test fixtures are inconsistent across the test suite — every test rebuilds its own data
  • A bug only reproduces with specific data and no seed covers that case
  • Multiple developers are stepping on each other's seed data in shared dev DB

When NOT to Use

  • Production data migration — that's database-design + a one-off backfill ADR
  • Schema design — that's database-design
  • Loading anonymized production data for analytics — separate concern, distinct safety rules

Common Rationalizations

Thought Reality
"Lorem ipsum is fine for now" Lorem ipsum in a demo makes the product look fake. The buyer notices in 4 seconds and you've already lost the deal.
"Just use 'Test User'" Homogeneous seed data hides bugs that only appear with real-world variance — long names, accents, no last name, multi-byte chars, all-caps.
"Seeds don't need to be idempotent" Non-idempotent seeds crash on the second run and corrupt the dev DB. Every developer ends up with a different shape.
"Edge cases in seed data are overkill" The bug you ship is always in the edge case you didn't seed. Empty list, single item, 10k items, missing optional field, deleted-but-referenced.
"We can use production data, it's anonymized" Anonymization is not a checkbox. Re-identification from indirect identifiers is trivial. Use synthesized data.
"Timestamps don't matter, just use now()" All-now() timestamps hide ordering bugs, time-based logic bugs, and "what does this look like with a year of history" bugs.

Read the full file on GitHub · 121 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. 9d ago First seen · 121 lines · 56 tokens per session scan A 003cf847bdf2

Subscribe to this mod's changes

seed-data-and-fixtures is a skill published in the GitHub repository aneja5/forge-skills (3 stars, last pushed 3mo ago), licensed MIT. It adds 56 tokens to every session and 1,617 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 2026-09-03.

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