Class McpProtocolException

Namespace

ModelContextProtocol

Assembly

ModelContextProtocol.Core.dll

Represents an exception that is thrown when a Model Context Protocol (MCP) protocol-level error occurs.

public class McpProtocolException : McpException, ISerializable

Inheritance

object

Exception

McpException

McpProtocolException

Implements

ISerializable

Derived

UrlElicitationRequiredException

Inherited Members

Exception.GetBaseException()

Exception.GetType()

Exception.ToString()

Exception.Data

Exception.HelpLink

Exception.HResult

Exception.InnerException

Exception.Message

Exception.Source

Exception.StackTrace

Exception.TargetSite

Exception.SerializeObjectState

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Remarks

This exception is used to represent failures related to protocol-level concerns, such as malformed JSON-RPC requests, unknown methods, unknown primitive names (tools/prompts/resources), or internal server errors. It is not intended to be used for tool execution errors, including input validation failures.

Tool execution errors (including input validation errors, API failures, and business logic errors) should be returned in the result object with IsError set to true, allowing language models to see error details and self-correct. Only protocol-level issues should throw McpProtocolException.

Message or ErrorCode from a McpProtocolException may be propagated to the remote endpoint; sensitive information should not be included. If sensitive details need to be included, a different exception type should be used.

Constructors

McpProtocolException()

Initializes a new instance of the McpProtocolException class.

public McpProtocolException()

McpProtocolException(string)

Initializes a new instance of the McpProtocolException class with a specified error message.

public McpProtocolException(string message)

Parameters

message string

The message that describes the error.

McpProtocolException(string, McpErrorCode)

Initializes a new instance of the McpProtocolException class with a specified error message and JSON-RPC error code.

public McpProtocolException(string message, McpErrorCode errorCode)

Parameters

message string

The message that describes the error.

errorCode McpErrorCode

An McpErrorCode.

McpProtocolException(string, Exception?)

Initializes a new instance of the McpProtocolException class with a specified error message and a reference to the inner exception that is the cause of this exception.

public McpProtocolException(string message, Exception? innerException)

Parameters

message string

The message that describes the error.

innerException Exception

The exception that is the cause of the current exception, or a null reference if no inner exception is specified.

McpProtocolException(string, Exception?, McpErrorCode)

Initializes a new instance of the McpProtocolException class with a specified error message, inner exception, and JSON-RPC error code.

public McpProtocolException(string message, Exception? innerException, McpErrorCode errorCode)

Parameters

message string

The message that describes the error.

innerException Exception

The exception that is the cause of the current exception, or a null reference if no inner exception is specified.

errorCode McpErrorCode

An McpErrorCode.

Properties

ErrorCode

Gets the error code associated with this exception.

public McpErrorCode ErrorCode { get; }

Property Value

McpErrorCode

Remarks

This property contains a standard JSON-RPC error code as defined in the MCP specification. Common error codes include:

• -32700: Parse error - Invalid JSON received
• -32600: Invalid request - The JSON is not a valid Request object
• -32601: Method not found - The method does not exist or is not available
• -32602: Invalid params - Malformed request or unknown primitive name (tool/prompt/resource)
• -32603: Internal error - Internal JSON-RPC error