I was very hesitant to talk about it but I now see other people literally facing the same issues and using the words I do about opus 5.
Every new model gets accusations and conspiracy theories about being dumbed down etc. I never went along with them and never really noticed it. I care only about...
Claude Opus 5 launched on July 24, 2026. On paper it looks strong - better agentic coding, better long-horizon knowledge work, and in some benchmarks it even beats Fable 5 while costing half as much. In practice, a large group of power users immediately started reporting that it:
There are multiple open GitHub issues on the Claude Code repo specifically about Opus models ignoring detailed CLAUDE.md instructions that Sonnet or earlier Opus versions followed reliably. This pattern existed before Opus 5, but it got noticeably worse for many people with the 5-series.