Have AI timelines suddenly moved? Re-examining Anthropic's acceleration and the flat frontier

A review of METR's report on AI R&D acceleration at Anthropic and the follow-on analyses finds Anthropic's capabilities growth shifted trend around October 2025, near Opus 4.5, but competing labs did not speed up and the overall frontier has stayed on its prior trend. The author weighs compute growth, which rose about 5.7-fold at Anthropic in 2025 versus 4.5-fold at OpenAI and 3.8-fold at Google DeepMind, against AI building AI, where METR attributes roughly 80% of the acceleration using redacted data outsiders cannot verify. Depending on which scenario holds, the chance of a superhuman AI researcher in 2027 ranges from about 70% under METR's headline figure to about 20% using only public Epoch numbers and the field's earlier trajectory.