{
  "instructions": [
    {
      "instruction": "Before choosing a pattern, state the concrete problem without pattern jargon: what conditional logic or coupling exists, what needs to vary independently, and what external system needs integration.",
      "relevant_when": "Evaluating a codebase to decide whether a design pattern applies",
      "why_given": "Step 1 of the workflow requires a concrete problem statement before pattern selection"
    },
    {
      "instruction": "When proposing a pattern, explicitly state the win condition: what complexity the pattern removes and what it adds. If the cost outweighs the benefit for simple code, recommend staying with the current approach.",
      "relevant_when": "Recommending or applying a design pattern",
      "why_given": "Step 2 requires evaluating pattern fit with an explicit win condition and cost/benefit analysis"
    },
    {
      "instruction": "Use the Strategy pattern to eliminate if/else chains or switch statements that select between interchangeable algorithms. Extract each branch into a class implementing a common interface.",
      "relevant_when": "Code contains conditional logic that selects between algorithm variants",
      "why_given": "Strategy pattern section: 'Use when: Conditional logic selects between algorithms'"
    },
    {
      "instruction": "Use the Adapter pattern when integrating an external or legacy API whose interface does not match your domain interface. Create a thin adapter class that translates between the two interfaces.",
      "relevant_when": "Integrating external APIs or legacy systems with incompatible interfaces",
      "why_given": "Adapter pattern section: 'Use when: Integrating external APIs or legacy systems with incompatible interfaces'"
    },
    {
      "instruction": "Use the Anti-Corruption Layer pattern to prevent external system design from polluting domain models. The ACL translates external data types to domain types and must live at the infrastructure boundary.",
      "relevant_when": "Integrating with external systems that have poor or incompatible domain models",
      "why_given": "Anti-Corruption Layer section prescribes this for preventing external pollution of the domain"
    },
    {
      "instruction": "NEVER apply patterns preemptively for imagined future needs. Apply a Factory or Strategy only when a second concrete implementation exists or complexity justifies it.",
      "relevant_when": "Evaluating whether to extract a pattern when only one implementation exists",
      "why_given": "Anti-pattern: NEVER apply patterns preemptively — wait for concrete need"
    }
  ]
}