Vercel AI SDK adds GitHub Copilot harness adapter
Vercel’s AI SDK harness layer (Sept 10) now supports GitHub Copilot via @ai-sdk/harness-github-copilot, so apps can swap Copilot in through the same HarnessAgent interface as Claude Code, Codex, Cursor, and others. The adapter talks ACP under the hood; no app-code change is needed to switch harnesses.
