Spencer Handley’s online guitar school, Sonora—which claims professional musicians such as Tom Misch and Billy Strings among its students—had been growing steadily for seven years, mostly unaffected by the spread of AI. Then came Claude Opus 4.5. The AI model, released by Anthropic in late November and trained on specialized data that taught it to complete long running agentic tasks, such as software engineering and administrative work, marked a step change in AI capability, according to