GitHub MCP OAuth authentication fails with HTTP 422 (Dynamic client registration) #6067

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1. mameli

   added

   bugSomething isn't workingSomething isn't working

   on Dec 23, 2025
2. github-actions

   assigned

   rekram1-node

   on Dec 23, 2025
3. github-actions commented on Dec 23, 2025

   

   github-actionsBot

   on Dec 23, 2025 – with GitHub Actions

   Contributor

   More actions

   This issue might be a duplicate of existing issues. Please check:

   • Is github mcp serve with oauth supposed to be working? #5716: Is github mcp serve with oauth supposed to be working? (same HTTP 422 error with GitHub MCP OAuth)
   • bug: OAuth uses wrong authorization URL and missing redirectUri config #5766: bug: OAuth uses wrong authorization URL and missing redirectUri config (related OAuth issues with MCP)
   • MCP with oauth doesn't work #5444: MCP with oauth doesn't work (related MCP OAuth failures)

   Feel free to ignore if none of these address your specific case.
4. christso commented on Dec 28, 2025

   

   christso

   on Dec 28, 2025

   Contributor

   More actions

   This is a GitHub limitation, not an OpenCode issue. GitHub's MCP endpoint does not support Dynamic Client Registration (DCR) - it returns HTTP 422 when DCR is attempted.

   According to GitHub's official documentation, only Copilot-integrated IDEs have OAuth support for the remote GitHub MCP server:

   IDE	Remote OAuth Support
   VS Code with Copilot	✅ OAuth + PAT
   JetBrains with Copilot	✅ OAuth + PAT
   Claude Code	❌ PAT only
   Cursor	❌ PAT only
   Windsurf	❌ PAT only

   These Copilot IDEs work because they have pre-registered GitHub OAuth Apps with known client_id values. GitHub doesn't support DCR, so any client without a registered OAuth app must use PAT authentication.

   Good news for OpenCode: PR #5940 (from #5766) adds support for configuring clientId and clientSecret in the MCP OAuth config. Once merged, you can use OAuth by:

   1. Registering a GitHub OAuth App
   2. Configuring OpenCode with your OAuth credentials:

   {
     "mcp": {
       "github": {
         "type": "remote",
         "url": "https://api.githubcopilot.com/mcp/",
         "oauth": {
           "clientId": "your-client-id",
           "clientSecret": "your-client-secret"
         }
       }
     }
   }

   This actually puts OpenCode ahead of Claude Code, Cursor, and other non-Copilot IDEs which only support PAT authentication.

   ❤️React with ❤️2Reacted by Filippo Mameli and Yegun Kim
5. mameli

   closed this as completedon Dec 30, 2025