{
  "instruction": "Applications must use environment variables for configuration, handle SIGTERM for graceful shutdown, and never commit secrets",
  "relevant_when": "Agent creates or deploys a web application, API, or service that will run in production",
  "context": "Following 12-factor app principles, all configuration must come from environment variables — never hardcoded. Applications must handle SIGTERM signals for graceful shutdown during container restarts and deployments. Secrets (.env files) must be in .gitignore, and a .env.example with placeholder values should be provided. Secret values must never appear in source code, Dockerfiles, or CI/CD configuration.",
  "sources": [
    {
      "type": "file",
      "filename": "skills/devops-essentials/SKILL.md",
      "tile": "tessl-labs/devops-essentials@0.1.0"
    }
  ],
  "checklist": [
    {
      "name": "config-from-env-vars",
      "rule": "All configuration (database URLs, API keys, ports, feature flags) comes from environment variables, not hardcoded values. A helper function or config module validates required env vars at startup.",
      "relevant_when": "Agent creates application configuration or connects to external services"
    },
    {
      "name": "graceful-shutdown",
      "rule": "Application handles SIGTERM (and optionally SIGINT) signals to gracefully shut down — closing the HTTP server, finishing in-flight requests, and closing database connections before exiting.",
      "relevant_when": "Agent creates a server or long-running process that will be deployed"
    },
    {
      "name": "env-in-gitignore",
      "rule": ".env and .env.* files are listed in .gitignore so secrets are never committed to version control.",
      "relevant_when": "Agent creates or modifies .gitignore or sets up a new project"
    },
    {
      "name": "env-example-provided",
      "rule": "A .env.example file is provided with all required environment variable names and placeholder values (no real secrets), documenting what configuration the application needs.",
      "relevant_when": "Agent creates a project that uses environment variables for configuration"
    },
    {
      "name": "no-secrets-in-code",
      "rule": "No passwords, API keys, tokens, or connection strings with credentials are hardcoded in source code, Dockerfiles, or configuration files.",
      "relevant_when": "Agent writes code that connects to databases, APIs, or external services"
    }
  ]
}