When to use each Claude model: Opus 5.5, Fable 5.2, Sonnet 5.5 and Haiku 5.5

Anthropic's guidance matches each Claude model to the scale of the work: Opus 5.5 for planning and building full features, and Fable 5.2 for the most ambitious, open-ended technical work. Sonnet 5.5 covers everyday tasks such as fixing a bug or drafting a doc, while Haiku 5.5 handles the smaller tasks done again and again.