What Is GitHub Copilot Fusion and Which Effort Level Should You Pick?
Copilot Fusion, generally available since October 28, 2026, is a runtime model router that picks a model and an execution pattern (Single, Cascade, or Critique) per prompt. Here is how the three patterns work, what Fusion Standard, High, and Max cost you in AI credits, how to lock the effort level with managed-settings.json, and the gotchas the docs bury.