GitHub Copilot Ships Multi-Agent VS Code and Replaces GPT-4 with In-House Project Polaris

Summary

At Microsoft Build 2026, GitHub unveiled two structural changes to Copilot. First, Project Polaris — Microsoft's proprietary mixture-of-experts coding model — will replace GPT-4 Turbo as the default engine for all Copilot subscribers starting in August 2026, ending Copilot's reliance on OpenAI models for its baseline experience. Microsoft claims Polaris outperforms GPT-4 Turbo on coding benchmarks, particularly for low-resource languages like Rust and Haskell, though independent verification is