Error Codes Reference

This page documents all standard error codes used across ACP implementations.

Error Response Patterns

AdCP uses different error handling patterns depending on the severity and context:

Task-Level Errors (Non-Fatal Warnings)

Use the optional errors array in successful responses for warnings and non-blocking issues:

{
  "message": "Operation completed with warnings",
 
  "context_id": "ctx-123",
  // ... task-specific success data ...
  "errors": [
    {
      "code": "ERROR_CODE",
      "message": "Human-readable description",
      "field": "field.path.with.issue",  // Optional
      "suggestion": "Recommended action",  // Optional
      "details": {
        // Additional context (optional)
      },
      "retry_after": 30  // Seconds to wait before retry (optional)
    }
  ]
}

Protocol-Level Errors (Fatal)

For operations that cannot be completed, use protocol-specific error mechanisms: MCP (Model Context Protocol):

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "content": [
      {
        "type": "text", 
        "text": "Failed to process request: Invalid credentials provided"
      }
    ],
    "isError": true
  }
}

A2A (Agent-to-Agent Protocol):

{
  "taskId": "task_123",
  "status": "failed",
  "message": {
    "parts": [{
      "kind": "text",
      "text": "Unable to complete operation: Authentication failed"
    }]
  }
}

Authentication Errors

INVALID_CREDENTIALS

Invalid or malformed authentication credentials. Example:

{
  "success": false,
  "error": {
    "code": "INVALID_CREDENTIALS",
    "message": "API key is invalid or has been revoked",
    "details": {
      "provided_key": "ak_live_123..."
    }
  }
}

Resolution: Verify API key is correct and active.

TOKEN_EXPIRED

Authentication token has expired. Example:

{
  "success": false,
  "error": {
    "code": "TOKEN_EXPIRED", 
    "message": "OAuth token expired",
    "details": {
      "expired_at": "2025-01-20T10:30:00Z"
    }
  }
}

Resolution: Refresh OAuth token or re-authenticate.

INSUFFICIENT_PERMISSIONS

Account lacks required permissions for the operation. Example:

{
  "success": false,
  "error": {
    "code": "INSUFFICIENT_PERMISSIONS",
    "message": "Account does not have activation permissions",
    "details": {
      "required_permission": "activate_signal",
      "account_permissions": ["get_signals", "check_signal_status"]
    }
  }
}

Resolution: Contact administrator to upgrade account permissions.

Validation Errors

MISSING_REQUIRED_FIELD

Required request parameter is missing. Example:

{
  "success": false,
  "error": {
    "code": "MISSING_REQUIRED_FIELD",
    "message": "prompt is required for signal discovery",
    "details": {
      "field": "prompt",
      "provided_fields": ["platform", "max_results"]
    }
  }
}

Resolution: Include all required fields in request.

INVALID_FIELD_VALUE

Field value doesn’t meet validation requirements. Example:

{
  "success": false,
  "error": {
    "code": "INVALID_FIELD_VALUE",
    "message": "max_results must be between 1 and 50",
    "details": {
      "field": "max_results",
      "provided_value": 100,
      "valid_range": "1-50"
    }
  }
}

Resolution: Provide valid field values per specification.

INVALID_FIELD_FORMAT

Field format is incorrect. Example:

{
  "success": false,
  "error": {
    "code": "INVALID_FIELD_FORMAT",
    "message": "reporting_date must be in YYYY-MM-DD format",
    "details": {
      "field": "reporting_date",
      "provided_value": "01/20/2025",
      "expected_format": "YYYY-MM-DD"
    }
  }
}

Resolution: Use correct field format as specified.

Resource Errors

SEGMENT_NOT_FOUND

Specified segment ID doesn’t exist or is no longer available. Example:

{
  "success": false,
  "error": {
    "code": "SEGMENT_NOT_FOUND",
    "message": "Segment ID not found or has expired",
    "details": {
      "segment_id": "seg_invalid_123",
      "suggestion": "Use get_signals to find current segment IDs"
    }
  }
}

Resolution: Use current segment ID from recent get_signals response.

SIGNAL_UNAVAILABLE

Signal exists but is not available for the requested platform/seat. Example:

{
  "success": false,
  "error": {
    "code": "SIGNAL_UNAVAILABLE",
    "message": "Signal not available for the specified platform",
    "details": {
      "segment_id": "seg_12345",
      "requested_platform": "unavailable_platform",
      "available_platforms": ["scope3", "thetradedesk"]
    }
  }
}

Resolution: Use available platform or check with provider.

Authorization Errors

PLATFORM_UNAUTHORIZED

Account lacks access to specified platform. Example:

{
  "success": false,
  "error": {
    "code": "PLATFORM_UNAUTHORIZED",
    "message": "Account not authorized for platform",
    "details": {
      "requested_platform": "restricted_platform",
      "authorized_platforms": ["scope3", "liveramp"]
    }
  }
}

Resolution: Use authorized platform or upgrade account access.

SEAT_UNAUTHORIZED

Account cannot access specified seat. Example:

{
  "success": false,
  "error": {
    "code": "SEAT_UNAUTHORIZED",
    "message": "Account cannot access seat",
    "details": {
      "requested_seat": "competitor_seat_001",
      "authorized_seats": ["brand_us_001", "brand_emea_002"]
    }
  }
}

Resolution: Use authorized seat or request access.

Operation Errors

ALREADY_ACTIVATED

Signal is already active for the specified platform/seat. Example:

{
  "success": false,
  "error": {
    "code": "ALREADY_ACTIVATED",
    "message": "Signal already activated for this platform and seat",
    "details": {
      "segment_id": "seg_12345",
      "platform": "scope3",
      "seat": "brand_us_001",
      "activated_at": "2025-01-15T10:30:00Z",
      "status": "deployed"
    }
  }
}

Resolution: Use existing activation or check status with check_signal_status.

ACTIVATION_FAILED

Signal activation process failed. Example:

{
  "success": false,
  "error": {
    "code": "ACTIVATION_FAILED",
    "message": "Failed to activate signal due to provider error",
    "details": {
      "segment_id": "seg_12345",
      "provider_error": "Segment temporarily unavailable",
      "retry_suggested": true
    },
    "retry_after": 300
  }
}

Resolution: Wait and retry, or contact support if persistent.

INVALID_PRICING_MODEL

Requested pricing model is not available for this signal. Example:

{
  "success": false,
  "error": {
    "code": "INVALID_PRICING_MODEL",
    "message": "CPM pricing not available for this signal",
    "details": {
      "segment_id": "seg_12345",
      "requested_model": "cpm",
      "available_models": ["revenue_share"]
    }
  }
}

Resolution: Use available pricing model or choose different signal.

Schema Version Errors

UNSUPPORTED_VERSION

Requested AdCP schema version is not supported by the server. Example:

{
  "success": false,
  "error": {
    "code": "UNSUPPORTED_VERSION",
    "message": "AdCP version '2.1.0' is not supported. Server supports versions compatible with 1.0.0 per semantic versioning.",
    "details": {
      "requested_version": "2.1.0",
      "current_server_version": "1.0.0",
      "compatibility_info": "Use versions 1.x.x for backward compatibility"
    }
  }
}

Resolution: Use a compatible schema version or upgrade to a server that supports the requested version.

Rate Limiting Errors

RATE_LIMIT_EXCEEDED

Too many requests within the rate limit window. Example:

{
  "success": false,
  "error": {
    "code": "RATE_LIMIT_EXCEEDED",
    "message": "Too many requests. Rate limit: 100 requests per minute",
    "details": {
      "limit": 100,
      "window": "60 seconds",
      "reset_time": "2025-01-20T15:31:00Z"
    },
    "retry_after": 45
  }
}

Resolution: Wait for rate limit window to reset before retrying.

System Errors

INTERNAL_SERVER_ERROR

Unexpected server error occurred. Example:

{
  "success": false,
  "error": {
    "code": "INTERNAL_SERVER_ERROR",
    "message": "An internal error occurred while processing the request",
    "details": {
      "request_id": "req_789123456",
      "timestamp": "2025-01-20T15:30:00Z"
    }
  }
}

Resolution: Retry request. Contact support if error persists.

SERVICE_UNAVAILABLE

External service dependency is temporarily unavailable. Example:

{
  "success": false,
  "error": {
    "code": "SERVICE_UNAVAILABLE", 
    "message": "Data provider service is temporarily unavailable",
    "details": {
      "provider": "LiveRamp",
      "estimated_recovery": "2025-01-20T16:00:00Z"
    },
    "retry_after": 900
  }
}

Resolution: Wait for service recovery and retry.

TIMEOUT

Request exceeded maximum processing time. Example:

{
  "success": false,
  "error": {
    "code": "TIMEOUT",
    "message": "Request exceeded 30 second timeout",
    "details": {
      "timeout_seconds": 30,
      "suggestion": "Try a more specific prompt or contact support"
    }
  }
}

Resolution: Refine request parameters or retry.

Data Errors

DATA_QUALITY_ISSUE

Data quality problem detected. Example:

{
  "success": false,
  "error": {
    "code": "DATA_QUALITY_ISSUE",
    "message": "Signal size data is stale",
    "details": {
      "segment_id": "seg_12345",
      "last_updated": "2024-12-01T00:00:00Z",
      "max_age_days": 30
    }
  }
}

Resolution: Contact provider for updated signal data.

USAGE_REPORT_REJECTED

Usage report failed validation. Example:

{
  "success": false,
  "error": {
    "code": "USAGE_REPORT_REJECTED",
    "message": "Negative impression count not allowed",
    "details": {
      "segment_id": "seg_12345",
      "field": "impressions",
      "provided_value": -1000,
      "validation_rule": "must be >= 0"
    }
  }
}

Resolution: Correct data and resubmit usage report.

Error Handling Best Practices

Retry Logic

Implement exponential backoff for retryable errors:

async function retryRequest(fn: Function, maxRetries = 3) {
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    try {
      return await fn();
    } catch (error) {
      if (error.code === 'RATE_LIMIT_EXCEEDED' && attempt < maxRetries) {
        const delay = Math.pow(2, attempt) * 1000; // Exponential backoff
        await new Promise(resolve => setTimeout(resolve, delay));
        continue;
      }
      throw error;
    }
  }
}

Error Categorization

Group errors by type for appropriate handling:

const RETRYABLE_ERRORS = [
  'RATE_LIMIT_EXCEEDED',
  'TIMEOUT', 
  'SERVICE_UNAVAILABLE',
  'INTERNAL_SERVER_ERROR'
];

const PERMANENT_ERRORS = [
  'INVALID_CREDENTIALS',
  'INSUFFICIENT_PERMISSIONS',
  'SEGMENT_NOT_FOUND',
  'PLATFORM_UNAUTHORIZED',
  'UNSUPPORTED_VERSION'
];

function isRetryable(errorCode: string): boolean {
  return RETRYABLE_ERRORS.includes(errorCode);
}

User-Friendly Messages

Convert technical errors to user-friendly messages:

const USER_MESSAGES = {
  'SEGMENT_NOT_FOUND': 'This signal is no longer available. Please search for signals again.',
  'RATE_LIMIT_EXCEEDED': 'Too many requests. Please wait a moment and try again.',
  'INSUFFICIENT_PERMISSIONS': 'Your account does not have permission for this action. Contact your administrator.',
  'UNSUPPORTED_VERSION': 'The requested schema version is not supported. Please use a compatible version.',
  // ... more mappings
};

function getUserMessage(errorCode: string): string {
  return USER_MESSAGES[errorCode] || 'An unexpected error occurred. Please try again.';
}

Getting Help

If you encounter errors not documented here:

Check the details field for additional context
Review request format against the specification
Contact platform support with the request_id if provided
Report new error patterns to help improve documentation

For technical support: support@adcontextprotocol.org

Getting Started

Protocols

Signals Protocol

Curation Protocol

Media Buy Protocol

Creative

Reference

​Error Codes Reference

​Error Response Patterns

​Task-Level Errors (Non-Fatal Warnings)

​Protocol-Level Errors (Fatal)

​Authentication Errors

​INVALID_CREDENTIALS

​TOKEN_EXPIRED

​INSUFFICIENT_PERMISSIONS

​Validation Errors

​MISSING_REQUIRED_FIELD

​INVALID_FIELD_VALUE

​INVALID_FIELD_FORMAT

​Resource Errors

​SEGMENT_NOT_FOUND

​SIGNAL_UNAVAILABLE

​Authorization Errors

​PLATFORM_UNAUTHORIZED

​SEAT_UNAUTHORIZED

​Operation Errors

​ALREADY_ACTIVATED

​ACTIVATION_FAILED

​INVALID_PRICING_MODEL

​Schema Version Errors

​UNSUPPORTED_VERSION

​Rate Limiting Errors

​RATE_LIMIT_EXCEEDED

​System Errors

​INTERNAL_SERVER_ERROR

​SERVICE_UNAVAILABLE

​TIMEOUT

​Data Errors

​DATA_QUALITY_ISSUE

​USAGE_REPORT_REJECTED

​Error Handling Best Practices

​Retry Logic

​Error Categorization

​User-Friendly Messages

​Getting Help