Anthropic recently gave me early access to a mystery model. They didn't tell me the name. I was sure it had to be Fable 5.5 or Fable 6, because it was such a massive leap over what I was getting from Fable.

It was Claude Opus 5.5. It's smarter than Fable and ChatGPT 6 Astra, faster, and cheaper. I’ve been using it for everything from reviewing code to building games and coming up with new projects.

When they took my access away before launch, I legitimately felt sad. That's how much I'd been using it.

You almost never get speed, intelligence, and cost all improving at once. Opus 5.5 is cheaper per task than any other model out there, and Anthropic actually cut the straight-up price. In the benchmarks, the high setting on Opus 5.5 beats the max setting on Astra 6.

Here are four ways to put Opus 5.5 to work, with prompts to try each one yourself.

1. Get a clear explanation

Since Opus 4.8 came out around May, basically every new model from every company has been unbearable to talk to. ChatGPT, Grok, all of them.

They drift into this weird jargon. "The smoke test has passed" a thousand times. You read paragraphs of it, get to the end, and think... what did I just read?

Opus 5.5 fixed that. It feels warm, human, and concise again, the way Sonnet 3.5 and Opus 4.5 used to.

Here's a real update it gave me mid-build:

"The full build and four tests are running in the background. About 30 minutes. I'll be notified when they finish."

That's it. When it's done, it tells you what it improved in simple bullets and tables. Give it something you want to understand (a piece of code, a project plan, or a technical concept) and ask it to explain it clearly. Use that explanation to decide what to do next.

Try this prompt:

Explain [code, plan, or concept] in plain English. Start with a short overview, then walk me through the important parts using a concrete example. Explain any technical terms as you go. Point out assumptions or gaps in the information I've given you. Finish with the most useful next step and why it matters.

2. Find problems you didn’t know existed

This is where the plain talk pays off. I took code Astra 6 had written, and Astra 6 was my go-to model up to this point. Then I gave it to Opus 5.5.

I didn't even ask it to debug. I just said, "Hey, can you improve these things?"

It came back with, basically, "By the way, I found all these issues. Want me to fix them?" It was finding problems left and right.

So don't wait for a new project to try it. Open something you've already built, ask for an improvement, and let it tell you what else it sees.

Try this prompt:

Review this project for bugs and things that don't work as intended. Trace the main user workflow and look for failure cases, including bad inputs and missing data. For each issue, show me where it happens, explain the impact, and suggest the smallest practical fix. Separate confirmed problems from things that need investigation, and prioritize what I should fix first.

3. Build the feature you’ve been putting off

The underrated part of Opus 5.5 is how few bugs it writes. It's shipping me more bug-free code than I've ever gotten before.

That changes what's worth attempting. In a few prompts, it built me a full top-down 3D extraction shooter with:

• A weapon inventory and equipment system
• A map with different locations
• Enemies and a full loot system
• Extraction, where you hold E to get out with everything you picked up

There was even more depth than I was getting out of Astra. And when I told it the game had issues, it tested the game itself and reported back what it saw, down to "You took 601 damage."

So pick the project you've been putting off because it felt too big. That's the one to hand it.

Try this prompt:

Help me build [feature or project] for [type of user]. The first version needs to [must-have behavior]. Ask me the questions you need answered before you start, then build the smallest version that delivers that result. Test the main workflow and likely failure cases. Show me how to try it, what you verified, and anything that still needs work.

4. Find your next project

If you're anything like me, you brainstorm with your models constantly. Opus 5.5 is the best model I've used for coming up with novel ideas.

I just bought the new Apple Watch Ultra 4, so I asked it: "Hey, can you help me come up with ideas for how we can hack this, apps we can put on it, different AI things we can do?"

It came back with a bunch of ideas. I said "yeah, that sounds good," and it built a custom watch app where I can see all my agents working and tap a button to talk to them or text them. No phone required.

I have no idea how Apple Watch apps work. It told me it had put the app on my watch. I said "no, you didn't." Then I looked down, and there it was.

Same story with my 17 computers. I asked what cool things we could do with local models, and it set up an entire local model system for me.

So take something you already own and ask it: "How would you use this? What would you build here?"

Try this prompt:

I have [device, tool, or interest], and I'd like to use it to [goal or recurring problem]. Suggest five useful things I could build, including a couple I probably wouldn't think of myself. For each, explain who it's for, how I'd use it, and what a small first version would include. Recommend one based on usefulness and effort, then help me take the first step.

One honest downside

The model is ahead of the harness. I don't think Claude Code's harness is as good as ChatGPT's yet. ChatGPT's voice mode is mind-blowingly good, and Claude's isn't quite there, though I'd expect Anthropic to improve it soon.

But the model is good enough that I still think you need to be using it.

Anthropic has been out of the game for about five months. Now they're back. And when these companies compete, we're the ones who win.

Btw, if you've got a project you want to point Opus 5.5 at, you don't have to figure it out alone. Bring it into the Vibe Coding Academy and we'll build it together.

Join the Vibe Coding Academy here.

Keep shipping,

Alex