Description

When a remote MCP server requiring OAuth 2.1 + PKCE is configured (Datadog), OpenCode registers a client ID successfully and writes it to mcp-auth.json, but never initiates the browser-based authorization flow.

The MCP toggles to "loading" then "failed" with:

• No auth URL surfaced to the user.
• No browser window opened.
• No error logged.

The mcp-auth.json entry is left with a clientId but no tokens. For comparison, the Atlassian remote MCP (same type: remote config) completes OAuth successfully and logs transport=StreamableHTTP connected with a full token set.

Plugins

• opencode-anthropic-auth@0.0.13
• @slkiser/opencode-quota@2.1.0

OpenCode version

1.2.15

Steps to reproduce

1. Add a remote MCP server that requires OAuth to opencode.json:

   {
     "mcp": {
       "datadog": {
         "enabled": true,
         "type": "remote",
         "url": "[https://mcp.datadoghq.eu/api/unstable/mcp-server/mcp?toolsets=core,apm,software-delivery](https://mcp.datadoghq.eu/api/unstable/mcp-server/mcp?toolsets=core,apm,software-delivery)"
       }
     }
   }