# Claude Code CLI - Error Handling Specifications

## Error Classification

### Severity Levels

| Level | Description | User Impact | Handling Approach |
|-------|-------------|------------|-------------------|
| Critical | Application cannot continue | Application termination | Immediate logging, clean shutdown, detailed recovery instructions |
| Major | Feature completely broken | Feature unavailable | Graceful degradation, alternative suggestion, detailed error message |
| Minor | Partial feature limitation | Reduced functionality | Warning message, continue with limited functionality |
| Informational | Non-disruptive issue | Minimal to none | Subtle notification, continue normal operation |

### Error Categories

| Category | Description | Examples |
|----------|-------------|----------|
| Authentication | Issues with user authentication | Invalid token, expired credentials, permission denied |
| Network | Connection and communication errors | API timeout, connection refused, SSL certificate error |
| File System | Issues with reading/writing files | Permission denied, file not found, locked file |
| Command Execution | Problems running terminal commands | Command not found, execution failure, timeout |
| AI Service | Issues with AI processing | Rate limit exceeded, invalid request, model error |
| Configuration | Problems with application setup | Invalid config format, missing required settings |
| Resource | System resource limitations | Out of memory, disk space exhausted |

## Error Handling Strategies

### Retry Mechanisms

- Exponential backoff for transient errors
- Configurable retry limits
- Progress notification during retries
- Fallback mechanisms after exhausting retries

### Graceful Degradation

- Feature-specific fallback modes
- Reduced functionality operation
- Local-only operation when cloud services unavailable
- Cache utilization for resilience

### User Notification

- Clear, actionable error messages
- Technical details available on demand
- Suggested remediation steps
- Links to relevant documentation

### Recovery Procedures

- Session state preservation
- Auto-save mechanisms
- Crash recovery on restart
- Transaction rollback for failed operations

## Error Tracking and Reporting

### Telemetry Collection

- Error frequency and patterns
- Environment context capture
- Anonymized error reports
- User-permitted crash reports

### Sentry Integration

- Real-time error tracking
- Exception grouping and analysis
- Performance impact assessment
- Release correlation

### Error Aggregation

- Pattern recognition across instances
- Prioritization based on impact
- Trend analysis for recurring issues
- User impact assessment

## Specific Error Handling Cases

### Authentication Errors

- Clear re-authentication instructions
- Token refresh attempts
- Credential validation checks
- Security-focused error messages

### API Communication Errors

- Connection diagnostics
- Network environment checks
- Request/response logging
- API status verification

### File System Errors

- Permission verification
- Path validation
- Resource availability checks
- Alternative storage suggestions

### Command Execution Errors

- Shell environment validation
- Dependency verification
- Command path verification
- Output/error stream capture

### AI Processing Errors

- Query validation
- Context size management
- Rate limit handling
- Model fallback options

## Error Logging

### Log Levels

| Level | Description | Information Included |
|-------|-------------|----------------------|
| ERROR | Significant problems | Error details, stack trace, context, user action |
| WARN | Potential issues | Warning details, related context, potential impact |
| INFO | Normal but significant events | Event description, relevant parameters |
| DEBUG | Detailed diagnostic information | Verbose execution details, state information |
| TRACE | Very detailed diagnostic information | Full execution path, variable states |

### Log Structure

```json
{
  "timestamp": "ISO-8601 timestamp",
  "level": "ERROR|WARN|INFO|DEBUG|TRACE",
  "message": "Human-readable message",
  "category": "Error category",
  "code": "Error code",
  "user": {
    "id": "Anonymized user identifier",
    "action": "User action that triggered the error"
  },
  "context": {
    "command": "Executed command",
    "file": "Relevant file path",
    "operation": "Operation being performed"
  },
  "technical": {
    "stack": "Stack trace (if applicable)",
    "raw": "Raw error details"
  },
  "session": {
    "id": "Session identifier",
    "duration": "Session duration in seconds"
  }
}
```

### Log Storage and Rotation

- Local log files with rotation
- Size and time-based rotation policies
- Compression of archived logs
- Automated cleanup of old logs

## User-Facing Error Messages

### Message Structure

- Clear problem statement
- Probable cause
- Suggested action
- Further information reference

### Localization

- Error message translation framework
- Locale-specific error resources
- Fallback to English for missing translations
- Cultural sensitivity in error messaging

### Visual Presentation

- Color-coding by severity
- Icons for error categories
- Progressive disclosure of technical details
- Contextual help links