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OAuth Flow not working for Atlassian MCP and Github MCP

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp, github

Research direction

Start with the ProtectedClient sample and its serverUrl set to https://api.githubcopilot.com/mcp/. Trace the OAuth metadata lookup that reports the missing .well-known/openid-configuration or .well-known/oauth-authorization-server metadata, then compare the GitHub and Atlassian flows. Done means the sample launches an authorization URL and completes authentication for the affected MCP servers.

Written by the indexing model from the issue text.

Description

area-auth bug needs confirmation P2

Describe the bug
The OAuth flow does not work for both Atlassian MCP and Github MCP when using the C# SDK. After initiating the authentication process, the redirect or token exchange does not complete successfully, resulting in authentication failure. It throws an error:

throw new McpException($"Failed to find .well-known/openid-configuration or .well-known/oauth-authorization-server metadata for authorization server: '{authServerUri}'");

Error Message is as follows:
ModelContextProtocol.McpException: 'Failed to find .well-known/openid-configuration or .well-known/oauth-authorization-server metadata for authorization server: 'https://github.com/login/oauth/''

To Reproduce
Steps to reproduce the behavior:

  1. Clone the csharp-sdk Repo
  2. Execute the "ProtectedClient" Repo and set the serverurl to var serverUrl = "https://api.githubcopilot.com/mcp/";
  3. Error is thrown, no OAuth flow gets initiated

Expected behavior
I expected it to launch an authorization URL that I can use to authenticate against Github or Atlassian, just like it works with FastMCP.

Dominant language
C#
Stars
4.5k
Forks
814
Avg merge
9d 19h
Merged PRs (30d)
4

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