cakemail-mcp-server/docs/AUTHENTICATION_ENHANCEMENT.md

Enterprise MCP server for Cakemail API integration with Claude AI - includes comprehensive template management, list management, sub-account management, BEEeditor visual email design, and advanced analytics

# Authentication Token Management Enhancement

This document outlines the comprehensive improvements made to the Cakemail MCP Server's authentication token management system.

## Problems Addressed

### 1. **No tools to check token status**
**Before**: No way to inspect token validity, expiry, or refresh status
**After**: New `cakemail_get_token_status` tool provides detailed token information

### 2. **No way to manually refresh tokens**
**Before**: Token refresh only happened automatically and couldn't be triggered manually
**After**: New `cakemail_refresh_token` tool allows manual token refresh with force option

### 3. **Token expiry handling could be more robust**
**Before**: Basic token refresh with limited error handling
**After**: Comprehensive token management with automatic refresh, fallback authentication, and detailed error handling

## New Authentication Tools

### 🔍 `cakemail_get_token_status`
Get comprehensive information about the current authentication token.

**Returns:**
- Token validity status
- Expiry date and time until expiry
- Refresh token availability
- Token type information

```json
{
  "hasToken": true,
  "isExpired": false,
  "expiresAt": "2025-06-19T15:30:00.000Z",
  "timeUntilExpiryMinutes": 45,
  "needsRefresh": false,
  "tokenType": "Bearer",
  "hasRefreshToken": true
}
```

### 🔄 `cakemail_refresh_token`
Manually refresh the authentication token with optional force parameter.

**Parameters:**
- `force` (boolean, optional): Force refresh even if token is still valid

**Returns:**
- Success/failure status
- Previous and new expiry times
- Error details if refresh fails

### ✅ `cakemail_validate_token`
Validate the current token by making a test API call.

**Returns:**
- Token validity confirmation
- Account information (if valid)
- Error details (if invalid)

### 🔐 `cakemail_get_token_scopes`
Get information about token permissions and available accounts.

**Returns:**
- Available account IDs
- Inferred permissions
- Scope information

## Enhanced BaseApiClient Features

### Automatic Token Management
- **Smart Token Refresh**: Automatically refreshes tokens 5 minutes before expiry
- **Fallback Authentication**: Falls back to password authentication if refresh fails
- **Token Validation**: Ensures valid token before every API request

### Robust Error Handling
- **Exponential Backoff**: Retry authentication with increasing delays
- **Invalid Token Detection**: Automatically clears invalid refresh tokens
- **Detailed Error Messages**: Comprehensive error reporting for debugging

### Enhanced Security
- **Token Expiry Buffer**: 1-minute safety buffer for token expiry
- **Secure Token Storage**: Tokens are not exposed in debug logs
- **Scope Management**: Proper scope handling for token requests

## Implementation Details

### Token Status Checking
```typescript
public getTokenStatus(): {
  hasToken: boolean;
  isExpired: boolean;
  expiresAt: Date | null;
  timeUntilExpiry: number | null;
  needsRefresh: boolean;
  tokenType: string | null;
  hasRefreshToken: boolean;
}
```

### Enhanced Authentication Flow
1. **Check Token Status**: Verify if current token is valid and not near expiry
2. **Smart Refresh**: Use refresh token if available and valid
3. **Fallback Authentication**: Use password authentication if refresh fails
4. **Retry Logic**: Implement exponential backoff for failed attempts
5. **Error Handling**: Provide detailed error information for debugging

### Request-Level Token Management
Every API request now:
1. Calls `ensureValidToken()` before execution
2. Automatically refreshes expired tokens
3. Falls back to full authentication if needed
4. Provides detailed error reporting

## Usage Examples

### Check Token Status
```javascript
// Get detailed token information
const status = await cakemail_get_token_status();
console.log(`Token expires in ${status.timeUntilExpiryMinutes} minutes`);
```

### Manual Token Refresh
```javascript
// Refresh token if needed
const result = await cakemail_refresh_token();

// Force refresh regardless of expiry
const forceResult = await cakemail_refresh_token({ force: true });
```

### Token Validation
```javascript
// Validate current token
const validation = await cakemail_validate_token();
if (validation.isValid) {
  console.log('Token is valid for account:', validation.accountInfo.id);
}
```

### Get Token Permissions
```javascript
// Check available permissions
const scopes = await cakemail_get_token_scopes();
console.log('Available accounts:', scopes.accounts);
console.log('Permissions:', scopes.permissions);
```

## Benefits

### For Developers
- **Better Debugging**: Detailed token status information
- **Manual Control**: Ability to force token refresh when needed
- **Error Transparency**: Clear error messages and status codes

### For Operations
- **Improved Reliability**: Automatic token management prevents authentication failures
- **Better Monitoring**: Token status can be checked programmatically
- **Reduced Downtime**: Fallback authentication ensures continuous operation

### For Security
- **Token Lifecycle Management**: Proper handling of token expiry and refresh
- **Scope Awareness**: Understanding of token permissions and limitations
- **Secure Defaults**: Conservative token handling with safety buffers

## Migration Notes

### Existing Code Compatibility
- All existing API calls continue to work without changes
- Token management is handled transparently
- No breaking changes to existing functionality

### New Capabilities
- Four new authentication tools are now available
- Enhanced debugging and monitoring capabilities
- Improved error handling and recovery

## Configuration

No additional configuration is required. The enhanced token management works with existing Cakemail API credentials:

```javascript
const api = new CakemailAPI({
  username: 'your-email@example.com',
  password: 'your-password',
  debug: true // Enable for detailed token management logs
});
```

## Testing

Run the authentication test suite to verify the implementation:

```bash
node tests/auth-test.js
```

This comprehensive enhancement makes the Cakemail MCP Server's authentication system much more robust, transparent, and developer-friendly while maintaining full backward compatibility.