- [The Coding Harness Behind GitHub Copilot in VS Code](https://code.visualstudio.com/blogs/2026/05/15/agent-harnesses-github-copilot-vscode) — VS Code team's breakdown of the coding harness behind GitHub Copilot: three core loop responsibilities (context assembly, tool exposure, tool execution), multi-provider model routing across Anthropic, Google, OpenAI, xAI, and Mistral, and the VSC-Bench eval suite with PR-gated assessment. The clearest published account of how a major product treats harness changes as first-class code review criteria — "the model is the engine, the harness is the car."