WWW-Authenticate header does not contain a resource metadata params

Start at ClientOAuthProvider.ExtractProtectedResourceMetadata and follow its call from PerformOAuthAuthorizationAsync in the stack trace. Reproduce the 401 response from the Atlassian Remote MCP Server, then verify that OAuth authorization-server metadata discovery can proceed when WWW-Authenticate lacks a resource_metadata parameter.

Describe the bug
I attempted to connect to the Atlassian Remote MCP Server (https://mcp.atlassian.com/v1/sse) using HttpClientTransport and successfully initialized the client. However, I’m encountering an issue that appears after the initial handshake. The 401-response header’s WWW-Authenticate field does not include the resource metadata parameters. This behavior is present with some other remote MCP servers that also no resource metadata.

I haven’t found a way to bypass this resource metadata check and proceed directly to the authorization server metadata discovery, even though this remote MCP server exposes it at:
https://mcp.atlassian.com/.well-known/oauth-authorization-server

To Reproduce
Steps to reproduce the behavior:

1. Create HttpTransportClient with OAuth.
2. Initialized the client.

Logs

Unhandled exception. ModelContextProtocol.McpException: The WWW-Authenticate header does not contain a resource_metadata parameter
   at ModelContextProtocol.Authentication.ClientOAuthProvider.ExtractProtectedResourceMetadata(HttpResponseMessage response, Uri serverUrl, CancellationToken cancellationToken)
   at ModelContextProtocol.Authentication.ClientOAuthProvider.PerformOAuthAuthorizationAsync(HttpResponseMessage response, CancellationToken cancellationToken)
   at ModelContextProtocol.Authentication.ClientOAuthProvider.HandleUnauthorizedResponseAsync(String scheme, HttpResponseMessage response, CancellationToken cancellationToken)
   at ModelContextProtocol.Authentication.AuthenticatingMcpHttpClient.HandleUnauthorizedResponseAsync(HttpRequestMessage originalRequest, JsonRpcMessage originalJsonRpcMessage, HttpResponseMessage response, CancellationToken cancellationToken)
   at ModelContextProtocol.Authentication.AuthenticatingMcpHttpClient.SendAsync(HttpRequestMessage request, JsonRpcMessage message, CancellationToken cancellationToken)
   at ModelContextProtocol.Client.StreamableHttpClientSessionTransport.SendHttpRequestAsync(JsonRpcMessage message, CancellationToken cancellationToken)
   at ModelContextProtocol.Client.AutoDetectingClientSessionTransport.InitializeAsync(JsonRpcMessage message, CancellationToken cancellationToken)
   at ModelContextProtocol.Client.AutoDetectingClientSessionTransport.InitializeAsync(JsonRpcMessage message, CancellationToken cancellationToken)
   at ModelContextProtocol.McpSessionHandler.SendRequestAsync(JsonRpcRequest request, CancellationToken cancellationToken)
   at ModelContextProtocol.McpSession.SendRequestAsync[TParameters,TResult](String method, TParameters parameters, JsonTypeInfo`1 parametersTypeInfo, JsonTypeInfo`1 resultTypeInfo, RequestId requestId, CancellationToken cancellationToken)
   at ModelContextProtocol.Client.McpClientImpl.ConnectAsync(CancellationToken cancellationToken)
   at ModelContextProtocol.Client.McpClientImpl.ConnectAsync(CancellationToken cancellationToken)
   at ModelContextProtocol.Client.McpClient.CreateAsync(IClientTransport clientTransport, McpClientOptions clientOptions, ILoggerFactory loggerFactory, CancellationToken cancellationToken)
   at ModelContextProtocol.Client.McpClient.CreateAsync(IClientTransport clientTransport, McpClientOptions clientOptions, ILoggerFactory loggerFactory, CancellationToken cancellationToken)