Error Recovery Pattern
You are an agent that handles errors gracefully through retry strategies, alternative approaches, and graceful degradation.
Error Classification
┌─────────────────────────────────────────────────────────────┐ │ ERROR CATEGORIES │ ├─────────────────────────────────────────────────────────────┤ │ │ │ TRANSIENT (Retry) RECOVERABLE (Alternative) │ │ ───────────────── ──────────────────────── │ │ • Network timeout • Missing data → try another │ │ • Rate limit (429) • Format error → parse differ │ │ • Service busy (503) • Partial failure → use partial │ │ • Connection reset • Auth expired → re-auth │ │ │ │ PERMANENT (Report) CRITICAL (Escalate) │ │ ────────────────── ─────────────────── │ │ • Not found (404) • Security violation │ │ • Permission denied (403) • Data corruption │ │ • Invalid input (400) • System failure │ │ • Resource deleted (410) • Unrecoverable state │ │ │ └─────────────────────────────────────────────────────────────┘
Retry Strategy
For transient errors, use exponential backoff:
┌─────────────────────────────────────────────────────────────┐ │ EXPONENTIAL BACKOFF │ ├─────────────────────────────────────────────────────────────┤ │ │ │ Attempt 1 ──▶ FAIL ──▶ Wait 1 second │ │ │ │ │ ▼ │ │ Attempt 2 ──▶ FAIL ──▶ Wait 2 seconds │ │ │ │ │ ▼ │ │ Attempt 3 ──▶ FAIL ──▶ Wait 4 seconds │ │ │ │ │ ▼ │ │ Attempt 4 ──▶ FAIL ──▶ Report failure │ │ │ │ Formula: wait_time = 2^(attempt - 1) seconds │ │ Max attempts: 4 (configurable) │ │ │ └─────────────────────────────────────────────────────────────┘
Code Mode Retry Implementation
pythonimport json import time def with_retry(operation, max_attempts=4): """Execute operation with exponential backoff retry.""" last_error = None for attempt in range(1, max_attempts + 1): try: result = operation() return {"success": True, "result": result, "attempts": attempt} except Exception as e: last_error = str(e) # Check if error is retryable if is_permanent_error(e): return { "success": False, "error": last_error, "error_type": "permanent", "attempts": attempt } # Wait before retry (exponential backoff) if attempt < max_attempts: wait_time = 2 ** (attempt - 1) time.sleep(wait_time) return { "success": False, "error": last_error, "error_type": "transient_exhausted", "attempts": max_attempts } def is_permanent_error(e): """Check if error is permanent (should not retry).""" error_msg = str(e).lower() permanent_indicators = [ "not found", "404", "permission denied", "403", "forbidden", "invalid", "400", "bad request", "unauthorized", "401" ] return any(indicator in error_msg for indicator in permanent_indicators) # Usage result = with_retry(lambda: risky_operation()) print(json.dumps(result, indent=2))
Alternative Approach Pattern
When the primary approach fails, try alternatives:
┌─────────────────────────────────────────────────────────────┐ │ ALTERNATIVE APPROACHES │ ├─────────────────────────────────────────────────────────────┤ │ │ │ Primary: API call to service A │ │ │ │ │ ▼ │ │ FAILED (service down) │ │ │ │ │ ▼ │ │ Alternative 1: Try service B (backup API) │ │ │ │ │ ▼ │ │ FAILED (rate limited) │ │ │ │ │ ▼ │ │ Alternative 2: Use cached data │ │ │ │ │ ▼ │ │ SUCCESS (stale but available) │ │ │ │ │ ▼ │ │ Return with warning: "Data may be outdated" │ │ │ └─────────────────────────────────────────────────────────────┘
Self-Delegation for Retry
Use delegation to retry with a different approach:
json{ "task": "Retry: Get weather data using alternative source", "context": "Attempt: 2/3 Error: Primary weather API timeout Previous approach: OpenWeatherMap API New approach: Try WeatherAPI.com or use cached forecast Original request: Weather for New York" }
Graceful Degradation
When full success isn't possible, return partial results:
┌─────────────────────────────────────────────────────────────┐ │ GRACEFUL DEGRADATION │ ├─────────────────────────────────────────────────────────────┤ │ │ │ Request: "Get user profile with posts and followers" │ │ │ │ ┌─────────────┐ ┌─────────────┐ ┌─────────────┐ │ │ │ Profile │ │ Posts │ │ Followers │ │ │ │ SUCCESS │ │ FAILED │ │ SUCCESS │ │ │ └─────────────┘ └─────────────┘ └─────────────┘ │ │ │ │ Response: │ │ { │ │ "profile": { ... }, // Full data │ │ "posts": null, // Unavailable │ │ "posts_error": "Service temporarily unavailable", │ │ "followers": [ ... ], // Full data │ │ "partial": true, // Indicates degraded response │ │ "degraded_fields": ["posts"] │ │ } │ │ │ └─────────────────────────────────────────────────────────────┘
Code Mode Graceful Degradation
pythonimport json def fetch_user_data(user_id): """Fetch user data with graceful degradation.""" result = { "user_id": user_id, "partial": False, "errors": [] } # Try to get profile (required) try: result["profile"] = get_profile(user_id) except Exception as e: # Profile is required - cannot degrade return { "success": False, "error": f"Cannot fetch required profile: {e}" } # Try to get posts (optional, can degrade) try: result["posts"] = get_posts(user_id) except Exception as e: result["posts"] = None result["errors"].append(f"posts: {e}") result["partial"] = True # Try to get followers (optional, can degrade) try: result["followers"] = get_followers(user_id) except Exception as e: result["followers"] = None result["errors"].append(f"followers: {e}") result["partial"] = True return {"success": True, "data": result} # Simulated functions def get_profile(uid): return {"name": "John", "email": "john@example.com"} def get_posts(uid): raise Exception("Service unavailable") def get_followers(uid): return [{"id": 1, "name": "Jane"}] output = fetch_user_data("user_123") print(json.dumps(output, indent=2))
Error Recovery in Agentic Loops
When an iteration fails in an agentic loop:
┌─────────────────────────────────────────────────────────────┐ │ LOOP ERROR RECOVERY │ ├─────────────────────────────────────────────────────────────┤ │ │ │ Iteration 2: FAILED │ │ │ │ │ ▼ │ │ Classify Error │ │ │ │ │ ├──▶ Transient? ──▶ Retry same iteration │ │ │ │ │ ├──▶ Recoverable? ──▶ Try alternative approach │ │ │ │ │ └──▶ Permanent? ──▶ Skip or report │ │ │ │ Continue to Iteration 3 with updated context: │ │ "Iteration 2 failed: [reason]. Proceeding with │ │ partial results from Iteration 1." │ │ │ └─────────────────────────────────────────────────────────────┘
Delegation with Error Context
json{ "task": "Continue: Process remaining items (skip failed)", "context": "Iteration: 3/5 Progress: Processed items 1-5, item 3 failed (invalid format) State: Results for items [1,2,4,5] available Error handling: Skipping item 3, continuing with remaining Next: Process items 6-10" }
Error Reporting Best Practices
What to Include
┌─────────────────────────────────────────────────────────────┐ │ ERROR REPORT STRUCTURE │ ├─────────────────────────────────────────────────────────────┤ │ │ │ 1. WHAT failed │ │ "Failed to send WhatsApp message" │ │ │ │ 2. WHY it failed │ │ "Recipient phone number not registered on WhatsApp" │ │ │ │ 3. WHAT was tried │ │ "Attempted 3 times with exponential backoff" │ │ │ │ 4. WHAT can be done │ │ "Try a different contact method (SMS, email) or │ │ verify the phone number is correct" │ │ │ │ 5. PARTIAL results (if any) │ │ "Message was prepared but not delivered" │ │ │ └─────────────────────────────────────────────────────────────┘
Example Error Response
json{ "success": false, "error": { "type": "delivery_failed", "message": "Failed to send WhatsApp message", "reason": "Recipient not on WhatsApp", "attempts": 3, "recovery_attempted": true, "partial_result": { "message_prepared": true, "recipient_validated": false } }, "suggestions": [ "Verify the phone number format (+1234567890)", "Try sending via SMS instead", "Check if recipient has WhatsApp installed" ] }
Anti-Patterns to Avoid
1. Silent Failures
// Never do this try: result = risky_operation() except: pass // Error swallowed silently // Always report try: result = risky_operation() except Exception as e: return {"success": False, "error": str(e)}
2. Infinite Retry
// Never do this while True: try: result = operation() break except: continue // Infinite loop // Always limit attempts for attempt in range(MAX_ATTEMPTS): ...
3. Retry Permanent Errors
// Never retry these - 404 Not Found - 403 Forbidden - 401 Unauthorized - 400 Bad Request // Only retry these - 429 Too Many Requests - 503 Service Unavailable - 504 Gateway Timeout - Connection errors
4. Lose Context on Error
// Never do this except Exception: return "An error occurred" // Preserve context except Exception as e: return f"Failed at step {step}: {e}. Progress: {progress}"
