The Agent Skills Directory

[CREDENTIALS_UNSAFE]: The skill correctly demonstrates the use of the Rails credentials system (Rails.application.credentials.dig) and environment variables to handle SMTP usernames and passwords, ensuring that no sensitive secrets are hardcoded within the source code.
[EXTERNAL_DOWNLOADS]: The skill references the letter_opener gem within the development group of the Gemfile. This is a well-known and standard industry tool used for previewing emails in a local browser environment without performing actual network-based delivery.
[COMMAND_EXECUTION]: File system access is limited to reading application assets (e.g., app/assets/images/logo.png) for inline attachments using File.read, which is a standard and safe operation within the context of generating emails.

rails-mailers