Anthropic makes Claude Opus 5.5 the default model on Pro, Max, Ultra and Team plans

Claude Opus 5.5 is now the default model in Claude on Pro, Max, Ultra and Team plans, and Anthropic recommends it as the daily driver for research, analysis and finished documents, decks and spreadsheets. Anthropic says Opus 5.5 at Medium effort matched or beat Opus 5 at High on its coding and knowledge-work evaluations, and in an internal merger-analysis test it finished in 63 minutes at half the cost of Opus 5 on the same task. The post also lists prompting changes for the new model, including dropping 'think hard' instructions, starting at Medium effort and attaching charts instead of retyping their values.