GitHub Copilot CLI Introduces Rubber Duck Dual-Model Review System

GitHub Copilot CLI is an AI tool that helps developers write, modify and debug code in the terminal. A single model, however, may perpetuate earlier errors, allowing problems to accumulate over multiple rounds of generation. To reduce risks in complex refactoring and other demanding tasks, GitHub has introduced an independent cross-model review that gives developers a second opinion at critical stages.

GitHub recently introduced an experimental feature called Rubber Duck, a dual-model system that uses AI models from different families. For example, Claude can perform a development task before GPT-5.4 independently reviews the work. GitHub has not announced a formal launch date, comprehensive performance data or pricing. For now, the focus is on testing whether cross-model checks can improve the quality of complex tasks.