I worked on this, and Opus 5.5 is our first model model release with targeted improvements on sentence clarity and overly-dense info dumps.
It's a hard problem to solve, and we'll continue to make improvements. But I haven't been as happy about a model's writing since Opus 4.6.
Opus 5.5 communicates more naturally, addressing some of the most common feedback we heard on Opus 5.
It puts the most important information up front and follows the writing rules you give it, which makes long sessions easier to follow.