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AI Governance, Resilience & Resilience Engineering

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1. Multi-Tier Safety Guardrails

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Tier 1: Identity & Quota Control

• Per-Lesson Quotas: Restricts in-lesson AI tutoring requests (AI_TUTOR_LESSON_LIMIT = 5 requests per lesson) to prevent automated scraping and encourage independent problem solving.
• Daily Quotas: Caps total daily requests per user (AI_TUTOR_DAILY_LIMIT = 20) to ensure equitable GPU resource allocation.
• Redis Atomic Tracking: Tracked atomically using Redis keys with automatic daily midnight expirations.

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Tier 2: Pre-Inference Sanitization & Profanity Filtering

• Incoming text is evaluated through containsProfanity() (ai-tutor.profanity.ts).
• Abusive or violating prompts are rejected immediately with a 400 Bad Request without consuming LLM inference tokens or backend latency.

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2. Upstream Resilience: Circuit Breakers & Timeout Races

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5-Second Latency Race (Promise.race)

private async callGeminiWithTimeout(prompt: string, timeoutMs: number = 5000): Promise<string> {
  const geminiCall = this.model.generateContent(prompt);
  const timeoutRace = new Promise<never>((_, reject) =>
    setTimeout(() => reject(new Error('AI generation timeout')), timeoutMs)
  );

  const response = await Promise.race([geminiCall, timeoutRace]);
  return response.response.text();
}

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Redis Circuit Breaker State Machine

1. Error Tracking: Consecutive failures increment ai:circuit:errors in Redis.
2. Tripping Threshold: When errors exceed the threshold (AI_TUTOR_CIRCUIT_ERROR_THRESHOLD = 5), the circuit trips open (ai:circuit:open).
3. Fail-Fast Fallback: While the circuit is open, subsequent AI requests immediately return graceful fallback messages without attempting upstream connections.
4. Automatic Reset: The circuit automatically resets after a cooldown period (AI_TUTOR_CIRCUIT_RESET_TTL = 120 seconds) to probe upstream recovery.

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3. Comprehensive AI Audit Telemetry (ai_analytics_logs)