Class McpException

Namespace

ModelContextProtocol

Assembly

ModelContextProtocol.Core.dll

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

public class McpException : Exception, ISerializable

Inheritance

object

Exception

McpException

Implements

ISerializable

Derived

McpProtocolException

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

The Message from a McpException might 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.

This exception type can be thrown by MCP tools or tool call filters to propagate detailed error messages from Message when a tool execution fails via a CallToolResult. This includes input validation errors, business logic errors, or any other failure that the model should be informed about. For example, if a required field is missing or a value is out of range, throwing an McpException with a descriptive message allows the model to understand the issue and potentially self-correct in a subsequent request.

For non-tool calls, this exception controls the message propagated via a JsonRpcError.

McpProtocolException is a derived type that can be used to also specify the McpErrorCode that should be used for the resulting JsonRpcError.

Constructors

McpException()

Initializes a new instance of the McpException class.

public McpException()

McpException(string)

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

public McpException(string message)

Parameters

message string

The message that describes the error.

McpException(string, Exception?)

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

public McpException(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.