Model catalog fails to load: `models.list` returns HTTP 403 despite valid Copilot entitlement

Short summary

The GitHub Copilot desktop app cannot load the Copilot model catalog. Model-list requests receive 403 Forbidden: forbidden: access denied.

Affected version or release

GitHub Copilot app 1.1.17; Copilot CLI 1.0.84-3

Installation context

macOS, Apple Silicon (aarch64); local desktop app

What happened?

The app falls back to provider models only. Creating or resuming a session also fails to list session models. The log records Request models.list failed with message: GenericFailure and HTTP 403 from the Copilot service.

Steps to reproduce

1. Open the GitHub Copilot desktop app.
2. Open the model picker or create/resume a session.
3. Observe that the Copilot model catalog does not load and the UI reports failure to list session models.

Expected behavior

The available Copilot model catalog should load successfully for the signed-in account.

Additional context

Account: bilchik

Copilot entitlement check reports:

• copilot_plan: individual
• chat_enabled: true

Troubleshooting completed:

• Reauthenticated through the Copilot CLI OAuth browser flow.
• Restarted the desktop app after reauthentication.
• Verified GitHub authorization and Copilot entitlement.
• CLI reports the latest available version.

The failure persists after these steps. This is a direct service response rather than a network/TLS failure.

Most recent Copilot service request ID: 975d4df9-ce62-484b-8c5d-9a46bd84c96b
Timestamp: 2026-09-10 13:48:46 UTC

Relevant response: 403 Forbidden: forbidden: access denied

I can provide the full app log if needed.

Start by reproducing the model-list request from the desktop app and reviewing the app log entry for Request models.list and the recorded service request ID. Compare the entitlement checks with the 403 response and determine whether the failure is in the app request or the Copilot service. Done means the model catalog and session model list load for an entitled account.