GitHub Copilot removed Claude Opus 4.6 from Pro mid-billing-cycle in April 2026 with minimal notice, breaking established prompt workflows developers had built on that specific model

In April 2026 GitHub Copilot moved Claude Opus 4.6 (previously available on the $10/month Pro plan) to Pro-only exclusion and introduced Opus 4.7 on Pro+ ($39/month) at a 7.5x token multiplier. Existing annual Pro subscribers found their established coding workflows using Opus broken mid-cycle with no automated migration path. The HN thread 'Changes to GitHub Copilot Individual Plans' reached 126 points with 100-plus comments, with multiple developers calling it 'quite the rug pull' and noting effective cost for Opus access increased 10-fold when accounting for tier differences. Developers who had built prompt chains and codebase-specific instructions tuned for a specific model version have no tool to automatically detect when a model they depend on is downgraded, removed, or moved to a higher tier, and no tool to evaluate which available alternative model produces the closest output on their existing prompt set.