BlogInside ARX
Fable 5.1, now live in ARX
Anthropic's latest model is running inside ARX from today. What changes for the agents doing your work, and a plain-English tour of what ARX actually is.
Anthropic released Claude Fable 5.1 this week, the latest model in the Claude 5 family and the strongest model they have shipped. As of today it is live in ARX. If your ARX is up to date, it is already there, doing the work.
What changes in ARX
The agents in ARX draft investor updates, chase debtors, read a month of sales calls, and assemble the Friday numbers. All of that runs through a model. When the model gets better, every one of those jobs gets better on the same day, without anyone in your company lifting a finger.
That is the quiet advantage of running your company on an AI Operating System rather than a pile of point tools. A tool you bought last year is the same tool today. ARX inherits every model release the week it lands, and Fable 5.1 is the biggest step since we moved to the Claude 5 family.
In our own use, the difference shows most on long, document-heavy work: the multi-source briefs, the contract stacks, the month-end packs where the old failure mode was losing the thread halfway through. We will publish more from our own workspaces as the results come in, and we would rather show you real output than quote a leaderboard.
What is ARX?
If you are arriving from the announcement, a short version.
ARX is Imperium's flagship desktop app: the AI Operating System as one installed application. One window with your company's knowledge, live numbers and agents behind it. You ask a question, you get an answer from your real data. You hand over a job, you get drafted work back, waiting for your approval.
ARX also ships white-labeled. GeoNet's team opens GeoNet OS. Trident's team opens Trident OS. Same engine underneath, each company's own name, mark and colours on top, installed on their machines and run by Imperium. ARX II, released this month, is the second generation of that app.
How to get it
If you are an Imperium client, you already have it. Open ARX and the newest model is doing your work now.
If you are not yet, the front door is the same as ever: the three-minute audit. It tells you what an AI Operating System would do inside your company, and whether ARX is the right shape for it.
