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igmarinigmarin/rails-agent-skills/skills/seed-database/SKILL.md

seed-database

Skill26 starsChanged 4 months agoMITView on GitHub

Use when choosing seeds, fixtures, or factories for Rails dev/test data. Seeds must be idempotent. Trigger words: seeds, fixtures, test data, development data.

  • Reads credentials

The file

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2 rules. About 0 are common, 2 are distinctive, and 0 are very specific to this project.

  • ≈0

    Common · estimate

    Many files like this have a rule of this kind.

  • ≈2

    Distinctive · estimate

    This author's own choices. Worth a look.

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    Very specific

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  • Common
  • Distinctive
  • Very specific
  1. Distinctive:

    Use idiomatic Rails seeding patterns.

    line 82
  2. Distinctive:

    Follow the credential and idempotency rules in HARD-GATE without exception.

    line 84

≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

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Files
SKILL.md

Seed Database

Manage development and test data effectively.

Quick Reference

UseSolution
Static reference datadb/seeds.rb with find_or_create_by!
Test scenariosFactoryBot in spec/factories/
Complex relationshipsBoth combined

HARD-GATE

NEVER commit production data to seeds
ALWAYS use factories for test-specific scenarios
ALWAYS make seeds idempotent (can run multiple times safely)
NEVER hardcode credentials (passwords, API keys, secrets) in seeds, factories, or examples
  - Use ENV variables (e.g., ENV.fetch('DEFAULT_SEED_PASSWORD')) or SecureRandom.hex(16) for non-production data
  - Use `rails credentials:edit` to manage production secrets, never commit them in code

Core Process

  1. Write idempotent seeds — use find_or_create_by! so re-runs are safe.
  2. Scope by environment — guard non-production data with Rails.env checks.
  3. Run seeds — execute rails db:seed (or rails db:setup for a fresh database).
  4. Validate idempotency — run rails db:seed a second time and confirm no duplicates or errors.
  5. Verify data — open rails console and spot-check expected records exist with correct attributes.

Minimal Inline Example

A copy-paste ready db/seeds.rb covering idempotency, environment scoping, and safe credentials:

# db/seeds.rb

# Static reference data — safe to run repeatedly
Role.find_or_create_by!(name: 'admin') do |r|
  r.description = 'Full system access'
end

Role.find_or_create_by!(name: 'member') do |r|
  r.description = 'Standard user access'
end

# Development-only seed data — never runs in production
if Rails.env.development?
  User.find_or_create_by!(email: 'admin@example.com') do |u|
    u.role       = Role.find_by!(name: 'admin')
    u.password   = ENV.fetch('DEFAULT_SEED_PASSWORD', SecureRandom.hex(16))
  end
end

For FactoryBot factory definitions and more complex relationship patterns, see EXAMPLES.md.

Extended Resources (Progressive Disclosure)

Load these files only when their specific content is needed:

  • EXAMPLES.md — Use when you need complete seeding examples with environment-specific patterns and FactoryBot factory definitions
  • references/workflow.md — Use when implementing complex seeding workflows or migration-dependent seed data

Output Style

  1. Use idiomatic Rails seeding patterns.
  2. Structure factories clearly.
  3. Follow the credential and idempotency rules in HARD-GATE without exception.
  4. Include verification commands: rails db:seed, a second idempotency run, and a rails console spot-check.
  5. Language — Must be in English unless explicitly requested otherwise.

Integration

SkillWhen to chain
write-testsWhen setting up test scenarios
review-migrationWhen ensuring DB schema is aligned

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