Remove error codes - we don't use those

Author: localden

src/ModelContextProtocol/McpAuthorizationException.cs

@@ -13,7 +13,7 @@ public class McpAuthorizationException : McpException
     /// Initializes a new instance of the <see cref="McpAuthorizationException"/> class.
     /// </summary>
     public McpAuthorizationException() 
-        : base("Authorization failed", McpErrorCode.Unauthorized)
+        : base("Authorization failed", McpErrorCode.InvalidRequest)
     {
     }
 
@@ -22,7 +22,7 @@ public McpAuthorizationException()
     /// </summary>
     /// <param name="message">The message that describes the error.</param>
     public McpAuthorizationException(string message) 
-        : base(message, McpErrorCode.Unauthorized)
+        : base(message, McpErrorCode.InvalidRequest)
     {
     }
 
@@ -32,37 +32,29 @@ public McpAuthorizationException(string message)
     /// <param name="message">The message that describes the error.</param>
     /// <param name="innerException">The exception that is the cause of the current exception, or a null reference if no inner exception is specified.</param>
     public McpAuthorizationException(string message, Exception? innerException) 
-        : base(message, innerException, McpErrorCode.Unauthorized)
+        : base(message, innerException, McpErrorCode.InvalidRequest)
     {
     }
 
     /// <summary>
     /// Initializes a new instance of the <see cref="McpAuthorizationException"/> class with a specified error message and error code.
     /// </summary>
     /// <param name="message">The message that describes the error.</param>
-    /// <param name="errorCode">The MCP error code. Should be either <see cref="McpErrorCode.Unauthorized"/> or <see cref="McpErrorCode.AuthenticationFailed"/>.</param>
+    /// <param name="errorCode">The MCP error code. Should use one of the standard error codes.</param>
     public McpAuthorizationException(string message, McpErrorCode errorCode) 
         : base(message, errorCode)
     {
-        if (errorCode != McpErrorCode.Unauthorized && errorCode != McpErrorCode.AuthenticationFailed)
-        {
-            throw new ArgumentException($"Error code must be either {nameof(McpErrorCode.Unauthorized)} or {nameof(McpErrorCode.AuthenticationFailed)}", nameof(errorCode));
-        }
     }
 
     /// <summary>
     /// Initializes a new instance of the <see cref="McpAuthorizationException"/> class with a specified error message, inner exception, and error code.
     /// </summary>
     /// <param name="message">The message that describes the error.</param>
     /// <param name="innerException">The exception that is the cause of the current exception, or a null reference if no inner exception is specified.</param>
-    /// <param name="errorCode">The MCP error code. Should be either <see cref="McpErrorCode.Unauthorized"/> or <see cref="McpErrorCode.AuthenticationFailed"/>.</param>
+    /// <param name="errorCode">The MCP error code. Should use one of the standard error codes.</param>
     public McpAuthorizationException(string message, Exception? innerException, McpErrorCode errorCode) 
         : base(message, innerException, errorCode)
     {
-        if (errorCode != McpErrorCode.Unauthorized && errorCode != McpErrorCode.AuthenticationFailed)
-        {
-            throw new ArgumentException($"Error code must be either {nameof(McpErrorCode.Unauthorized)} or {nameof(McpErrorCode.AuthenticationFailed)}", nameof(errorCode));
-        }
     }
 
     /// <summary>

src/ModelContextProtocol/McpErrorCode.cs

@@ -46,20 +46,4 @@ public enum McpErrorCode
     /// This error is used when the endpoint encounters an unexpected condition that prevents it from fulfilling the request.
     /// </remarks>
     InternalError = -32603,
-
-    /// <summary>
-    /// Indicates that the client is not authorized to access the requested resource.
-    /// </summary>
-    /// <remarks>
-    /// This error is returned when the client lacks the necessary credentials or permissions to access a resource.
-    /// </remarks>
-    Unauthorized = -32401,
-
-    /// <summary>
-    /// Indicates that the authentication process failed.
-    /// </summary>
-    /// <remarks>
-    /// This error is returned when the client provides invalid or expired credentials, or when the authentication flow fails.
-    /// </remarks>
-    AuthenticationFailed = -32402,
 }

src/ModelContextProtocol/Protocol/Auth/DefaultAuthorizationHandler.cs

@@ -193,7 +193,7 @@ public async Task<bool> HandleUnauthorizedResponseAsync(HttpResponseMessage resp
             _logger.LogError(ex, "Failed to complete authorization flow");
 
             var authException = new McpAuthorizationException(
-                $"Failed to complete authorization flow: {ex.Message}", ex, McpErrorCode.AuthenticationFailed);
+                $"Failed to complete authorization flow: {ex.Message}", ex, McpErrorCode.InvalidRequest);
 
             authException.ResourceUri = resourceMetadata.Resource;
             authException.AuthorizationServerUri = authServerUrl;

src/ModelContextProtocol/Protocol/Transport/SseClientTransport.cs

@@ -120,12 +120,12 @@ public SseClientTransport(SseClientTransportOptions transportOptions, HttpClient
                     if (!string.IsNullOrEmpty(error))
                     {
                         responseHtml = $"<html><body><h1>Authorization Failed</h1><p>Error: {error}</p></body></html>";
-                        authCodeTcs.SetException(new McpException($"Authorization failed: {error}", McpErrorCode.AuthenticationFailed));
+                        authCodeTcs.SetException(new McpException($"Authorization failed: {error}", McpErrorCode.InvalidRequest));
                     }
                     else if (string.IsNullOrEmpty(code))
                     {
                         responseHtml = "<html><body><h1>Authorization Failed</h1><p>No authorization code received.</p></body></html>";
-                        authCodeTcs.SetException(new McpException("No authorization code received", McpErrorCode.AuthenticationFailed));
+                        authCodeTcs.SetException(new McpException("No authorization code received", McpErrorCode.InvalidRequest));
                     }
                     else
                     {