Power BI MCP: re-auth fails after token expiry (no refresh token from Fabric endpoint) #1965

Summary

The powerbi-remote MCP server (Fabric Power BI endpoint) fails to re-authenticate after the access token expires (~1 hour), producing AADSTS50011 (redirect URI mismatch). This blocks all Power BI tool calls in sessions longer than 1 hour.

Dataverse MCP servers do not have this issue because they receive refresh tokens.

Reproduction

1. Start a new CLI session with a plugin that defines a type: "http" Power BI MCP server:

   {
     "powerbi-remote": {
       "type": "http",
       "url": "https://api.fabric.microsoft.com/v1/mcp/powerbi"
     }
   }

2. Authenticate when the browser prompt appears at session start — this succeeds.
3. Wait ~1 hour for the access token to expire (or work in the session until it expires naturally).
4. Call any Power BI tool (e.g., ExecuteQuery, GetSemanticModelSchema).
5. A new browser login prompt appears, then fails with:

   AADSTS50011: The redirect URI 'http://127.0.0.1:60759/' specified in the request
   does not match the redirect URIs configured for the application 'aebc6443-996d-45c2-90f0-388ff96faa56'.
   

Root Cause

Inspecting ~/.copilot/mcp-oauth-config/, the cached OAuth data reveals the difference:

When the Power BI access token expires:

1. There is no refresh token, so the CLI must do a full authorization code flow.
2. The CLI opens a local HTTP server on a new random port (e.g., :60759).
3. The Azure AD app (aebc6443-...) only has the original port (e.g., :53820 from session start) registered.
4. Azure AD rejects the new redirect URI.

Dataverse avoids this entirely by issuing a refresh token, allowing silent renewal without a browser flow.

Expected Behavior

Power BI tools should continue working after the initial 1-hour token expires, either by:

1. Obtaining a refresh token from the Fabric endpoint (preferred — matches Dataverse behavior)
2. Reusing the original redirect URI port when re-authentication is required
3. Re-registering the new redirect URI via Dynamic Client Registration before attempting re-auth

Environment

• CLI Version: 1.0.4
• OS: Windows 11
• Plugins affected: Any plugin using type: "http" with the Fabric Power BI endpoint
• Not affected: Dataverse MCP servers (they have refresh tokens), stdio MCP servers

Workaround

Restart the CLI session to get a fresh token. All Power BI calls must complete within ~1 hour of session start.