> ## Documentation Index
> Fetch the complete documentation index at: https://apidocs.ermbot.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Error Handling Protocol

> Comprehensive error handling specification

## Error Response Protocol

The API implements a standardized error response schema:

```typescript theme={null}
interface ErrorResponse {
  status: number;      // HTTP status code
  message: string;     // Human-readable description
  error_code: string;  // Machine-parseable identifier
}
```

## Error Classification Hierarchy

### Database Operation Failures (500)

MongoDB operation exception handling:

```json theme={null}
{
  "status": 500,
  "message": "Database operation failed: write concern error",
  "error_code": "DATABASE_ERROR"
}
```

### Resource Resolution Failures (404)

Entity resolution exception handling:

```json theme={null}
{
  "status": 404,
  "message": "Resource not found in collection",
  "error_code": "NOT_FOUND"
}
```

### Request Validation Failures (400)

Schema validation exception handling:

```json theme={null}
{
  "status": 400,
  "message": "Invalid input: constraint violation",
  "error_code": "INVALID_INPUT"
}
```

### System-Level Failures (500)

Runtime exception handling:

```json theme={null}
{
  "status": 500,
  "message": "Internal error: system constraint violation",
  "error_code": "INTERNAL_ERROR"
}
```

### Rate Limit Exceptions (429)

Throughput constraint violations:

```json theme={null}
{
  "status": 429,
  "message": "Rate limit exceeded: throughput constraint violation",
  "error_code": "RATE_LIMIT_EXCEEDED"
}
```

## Exception Handling Implementation

### Best Practices

1. Implement status code validation
2. Parse error\_code enum values
3. Log message content for debugging
4. Implement exponential backoff for 429
5. Handle 500-level errors with circuit breaking