The move is internal toolchain consolidation, not a falling-out with Anthropic — Claude Sonnet 4.5, Opus 4.1, and Haiku will remain accessible inside Copilot CLI. Engineers lose the standalone Claude Code interface; they keep the models. It's a telling sign of where Microsoft sees the leverage: owning the shell matters more than which LLM sits behind it. Teams on standalone Claude Code licenses before June 30 should validate that their workflows translate cleanly to the Copilot CLI equivalents.