GitHub Copilot

GitHub Copilot has no supported setting for a custom model backend. It can be pointed at a local proxy URL through a debug override, which the gateway can serve.

Heads up: this is an unsupported, best-effort setup. The override key lives under Copilot's advanced / debug settings and GitHub can remove or rename it at any release. Inline completions may ignore it. If you need something dependable, use Claude Code, OpenCode, or the generic recipe.

What you get

• Copilot Chat requests routed through the gateway onto your project's sponsor budget, on the releases where the override still works.

Prerequisites

• Your project access key and base URL from your project control panel — YOUR_PROJECT_KEY and https://v1.opentokenmarket.dev.
• VS Code with the GitHub Copilot and Copilot Chat extensions installed and signed in.

Configure

Open VS Code settings.json (Cmd/Ctrl + Shift + P → Preferences: Open User Settings (JSON)) and add:

{
  "github.copilot.advanced": {
    "debug.overrideProxyUrl": "https://v1.opentokenmarket.dev",
    "debug.testOverrideProxyUrl": "https://v1.opentokenmarket.dev"
  }
}

The gateway authenticates you from the request; there is no separate key field in Copilot's settings. If your editor build exposes a key/token field under github.copilot.advanced, set it to YOUR_PROJECT_KEY.

Restart VS Code fully after saving.

Run

Open Copilot Chat and send a message. Model selection, where available, uses Copilot's own model list.

Verify

Confirm the gateway itself is reachable with your key:

curl https://v1.opentokenmarket.dev/chat/completions \
  -H "Authorization: Bearer YOUR_PROJECT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-4o","messages":[{"role":"user","content":"ping"}]}'

If that succeeds but Copilot still uses GitHub's backend, the override isn't taking effect on your Copilot build — that's the limitation noted above.

Troubleshooting

• No change after editing settings — you didn't fully restart VS Code, or your Copilot version dropped the override key. There is no workaround; switch to a supported tool.
• 401 from the gateway — the key isn't your project access key.
• budget has been exceeded — ask your sponsor to top up the project.

Which model names to use

Copilot picks its own model names. The model catalog lists what this gateway can actually serve.