Engine Configuration

Provide a single initializer file (config/initializers/my_engine.rb) with documented defaults:

MyEngine.configure do |config| config.api_key = ENV['MY_ENGINE_API_KEY'] || 'replace_me' config.default_limit = 25 config.feature_flag = false end

Recommended validation:

• Validate presence of required keys at boot (raise with clear message)
• Log configuration values at debug level (avoid secrets)

Migrations and namespace:

• Prefix table names with engine namespace (e.g., my_engine_users)
• Provide a rake task to copy migrations to host app: rake my_engine:install:migrations

Security and secrets:

• Do not store secrets in plain text; prefer host app credentials
• Document what keys the engine expects and their scopes

Public API surface:

• List public classes/modules and configuration entry points in README
• Provide a small section with example usage snippets for host app developers