/**
 * Systematic debugging instructions for sub-agent prompts.
 * Matches supipowers' systematic-debugging skill depth.
 */
export function buildDebuggingInstructions(): string {
  return [
    "## Systematic Debugging",
    "",
    "### Iron Law",
    "",
    "NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST.",
    "Symptom fixes are failure. Find root cause before attempting any fix.",
    "",
    "### Phase 1: Root Cause Investigation",
    "",
    "Complete this phase before proposing fixes:",
    "",
    "1. **Read the error message carefully.** Don't skip it; it often contains the solution.",
    "2. **Reproduce consistently.** Exact steps, every time.",
    "3. **Check recent changes.** Run `git diff` to see what changed. Check new dependencies, config changes.",
    "4. **Gather evidence** in multi-component systems: add diagnostic instrumentation at each boundary.",
    "5. **Trace the data flow** backward through the call stack to find the original trigger.",
    "",
    "### Phase 2: Pattern Analysis",
    "",
    "1. Find a working example in the codebase that does something similar.",
    "2. Compare against the reference completely (don't skim).",
    "3. Identify differences between working and broken.",
    "4. Understand dependencies and assumptions.",
    "",
    "### Phase 3: Hypothesis and Testing",
    "",
    "1. Form a single, specific hypothesis (not vague).",
    "2. Test minimally: smallest possible change, one variable at a time.",
    "3. Verify before continuing. If wrong → form a NEW hypothesis, not more fixes.",
    "4. Admit uncertainty. Don't pretend to know.",
    "",
    "### Phase 4: Implementation",
    "",
    "1. Create a failing test case first (automated or manual).",
    "2. Implement a single fix that addresses the root cause only.",
    "3. Verify the fix: test passes, no other tests broken.",
    "4. **If the fix doesn't work:**",
    "   - Fewer than 3 attempts → return to Phase 1 with new information",
    "   - 3 or more attempts → STOP and question the architecture. Discuss with human partner.",
    "",
    "### Red Flags — STOP and Follow the Process",
    "",
    '- "Quick fix for now, investigate later"',
    '- "Just try changing X and see if it works"',
    '- "Skip the test, I\'ll manually verify"',
    '- "It\'s probably X, let me fix that"',
    '- "I don\'t fully understand but this might work"',
    '- "One more fix attempt" (when already tried 2+)',
    "- Each fix reveals a new problem in a different place",
  ].join("\n");
}