External Validation

Protocol for invoking external LLM validation to provide unbiased critique of artifacts.

Core Principle

WHY External Validation: Internal validation (same model that created the artifact) can suffer from:

• •Model blindness (model won't catch its own mistakes)
• •Confirmation bias (validating own reasoning)
• •Pattern repetition (same model, same blind spots)

External validation uses a DIFFERENT model to provide fresh perspective.

When to Use External Validation

Model Selection Strategy

Rule: External validator MUST be a different model family than the creator.

Feedback Merging Protocol

When combining internal and external validation feedback:

1. •Status: FAIL if either validator fails
2. •Issues: Combine and deduplicate from both validators
3. •Trust external: If external finds critical issues internal missed

Status File Integration

{
  "stages": {
    "validate-prd": {
      "status": "completed",
      "output": "PRD validated",
      "validator": "internal + gemini-3.0-pro"
    }
  },
  "externalValidation": {
    "prdValidation": {
      "status": "completed",
      "model": "gemini-3.0-pro",
      "result": "PASS",
      "issues": 0
    }
  }
}

Error Handling

If external service is unavailable:

• •Fall back to internal validation only
• •Record skipped status with reason
• •Continue pipeline with warning

Anti-Patterns

• •❌ Using same model for external validation
• •❌ Skipping external validation on complex PRDs
• •❌ Ignoring external feedback when internal passes

Environment Variables

EXTERNAL_VALIDATE=true              # Enable external validation
EXTERNAL_VALIDATION_MODEL="gemini-3.0-pro"  # Model to use
EXTERNAL_VALIDATION_TIMEOUT=30000   # 30 seconds