Rubber Duck in GitHub Copilot CLI now supports more models

Source: GitHub Changelog

Rubber Duck, the cross‑family review agent in GitHub Copilot CLI, is now available using a Claude‑powered critic agent when your session is using a GPT model. For sessions using Claude as their orchestrator, the GPT model used to seek a second opinion has been upgraded.

What’s new

• Rubber Duck for GPT sessions: When you’ve selected a GPT model as your orchestrator and /experimental is enabled, Copilot will dispatch a Claude‑powered Rubber Duck agent to provide a second opinion. The same second‑opinion benefits (architectural catches, subtle bugs, and cross‑file conflicts) now apply to GPT‑driven sessions.

• Stronger reviewer models for Claude sessions: Claude orchestrator sessions can now pair with GPT‑5.5 as the Rubber Duck model for more effective second opinions.

To try it, run copilot and ensure /experimental on is toggled.

Learn more about how Rubber Duck combines model families to improve Copilot CLI’s performance in our recent blog post.