Opus 5.5 Puts "the Important Part First" — and Your Writing Requests Land Better

What changed: replies now put "the important part first"

According to Anthropic's announcement, Opus 5.5 greatly improves "writing," one of the more common pieces of feedback on the previous model (Opus 5). There are three changes.

First, it puts the important information first. Second, it is less likely to use jargon or idiosyncratic phrases. Third, it follows the writing rules you give it.

The announcement says early testers felt its writing had become clearer and easier to take in at a glance. The most important thing comes in the first few lines of the reply. That is the heart of this change.

Why it helps people starting from zero knowledge

When you hand off work with zero knowledge, you often can't understand everything in a reply. What you rely on then is being able to tell right away "did it work in the end?" and "what should I do next?"

The announcement also shares early users' feedback that replies you can grasp at a glance helped during long working sessions. In work that goes back and forth dozens of times, the difference in reading effort per reply adds up.

Less jargon matters a lot too. Cut down "time spent looking up unfamiliar words" and you can focus that much more on what you want to build. You can decide your next move without reading the reply all the way through.

How to ask first: add one line of writing rules

Of the three changes, "follows the writing rules you give it" is worth using actively. If replies feel hard to read, it's a good idea to state the format that's easy for you to read up front.

Here's what the instruction actually looks like.

$ claude
> In your replies, write the conclusion in one line first.
> When you use technical terms, rephrase them in words someone with zero knowledge can understand.

Rather than just "write clearly," it gets across better when you shape it into concrete rules, like "conclusion in one line first" and "rephrase technical terms." You can order the way replies are written, just like you order the thing you want built.

Summary

With Opus 5.5, replies start with the important part and use less jargon. Add your writing rules, and they come back in the form that's easiest for you to read. You spend less time decoding replies and more time on what you want to build.

Telling it "how you want the reply" is also a way of thinking you can keep using as models get updated. Ordering the shape of the reply pays off every time you ask for something, whether it's building a page, design, or writing.

The next time you ask for something, try adding one line: "conclusion in one line first."