🥊 Claude Opus 4.6 vs GPT-5.3 Codex: Which AI Model Wins in 2026? (Honest Review)

I. Introduction

Well, I think 2026 will be a crazy year for the AI industry. We’re only in the second month of the year but we are seeing something absolutely wild unfold and I’m not talking about corporate fluff or "staged" product demos. This is a rare moment of open, public conflict in the AI industry.

2026 is the year Anthropic (Claude) and OpenAI (ChatGPT) decided to go nuclear on each other. And on the same day, they both launched their best models ever, dropped competing Super Bowl ads and started a public fight on social media.

Think of this as the "Kendrick vs. Drake" of the tech world but instead of diss tracks, these companies are dropping their new models. If you thought the AI space was chaotic before, you haven't seen anything yet.

Let’s break down the absolute cinema that just took place.

II. How Big Is The Real Size Gap Between ChatGPT and Claude?

ChatGPT and Claude operate at very different scales. In 2025, ChatGPT had around 1.2-1.5 billion monthly users. Claude had about 18.9 million.

Key takeaways

• ChatGPT is used by ~92% of Fortune 500 companies.

• Claude operates at a much smaller, developer-heavy scale.

• What tech experts say online is not the same as what most people actually use.

• Reputation and adoption are not the same thing.

Developer hype can hide massive differences in real-world usage:

• ChatGPT has around 1.2-1.5 billion monthly users. It is the primary tool for over 92% of Fortune 500 companies.

• Claude has about 18.9 million users.

That means ChatGPT has ~63-79 times more users than Claude. Even Perplexity, DeepSeek and Google Gemini have more users than Claude.

But here's the strange part: if you spend time in tech circles online, everyone acts like Claude is the dominant coding assistant. Developers love it and it shows up in every "best AI tools" thread. The gap between reputation and actual usage is massive.

So when Anthropic decided to pick a fight with OpenAI, it looked a lot like a challenger walking into the champion's gym and talking trash.

III. The Super Bowl Ad That Started the AI Competition

The Super Bowl is the biggest advertising stage in the U.S., where every second costs a fortune and every message is polished to feel safe. This year, both major AI companies showed up.

• OpenAI used its slot to show a safe, inspiring vision of AI.

• Anthropic, however, decided to lob a marketing grenade.

The ad shows a person asking their AI assistant a genuine question: "How do I communicate better with my mom?"

The context of the video is that the AI starts with sincere advice on communicating better with your mom, then it suddenly starts trying to sell a dating site for older women. The person freezes. “What?” The AI follows up: “Want me to create your profile?”

The ad ends there, leaving the moment hanging. You can watch the full ads here if you want the full context and this is just one of the four videos they released.

1. Why This Ad Hit Hard

I must say that the timing wasn’t just an accident.

OpenAI had recently announced plans to introduce ads to support a free tier and make AI more accessible without forcing everyone into a monthly subscription (about $20/month).

But they were also clear about one thing: ads would stay outside of the chat and be clearly marked as ads, not mixed into the AI’s actual replies.

Anthropic's ad shows exactly that nightmare scenario: an AI interrupting a personal, emotional conversation to sell something. It's a direct shot at OpenAI's monetization strategy.

What makes the ad effective is that Anthropic never explicitly said "this is what ChatGPT will do". They just showed what ads in AI could look like. That ambiguity is the trick that allows the message to land without making a direct accusation.

2. How People Reacted

Rapidly, the internet split into two camps:

• Camp 1: "This is genius. I’m crying laughing".

• Camp 2: "This is dishonest. OpenAI never said ads would work like this. Anthropic is spreading fear".

For me, both sides had a point. Anthropic didn't lie but they definitely implied something misleading. It lived in the gray area, wrapped in humor.

Most people watching the Super Bowl have no idea who Anthropic is. They didn’t understand the context, the rivalry or the inside joke.

The ad was speaking to a very small, informed audience while airing on the biggest mainstream stage possible.

IV. Sam Altman Steps In (And Maybe Shouldn't Have)

Once the ad started spreading online, it didn’t take long for Sam Altman, OpenAI's CEO, to respond publicly.

His core points were straightforward:

• "They are funny and I laughed. But I wonder why Anthropic would go for something so clearly dishonest. Our most important principle for ads says that we won’t do exactly this".

• "We believe everyone deserves to use AI and are committed to free access, because we believe access creates agency".

Then he added a joke:

"More Texans use ChatGPT for free than the total number of people using Claude in the entire US. We have a differently shaped problem than they do".

It was a solid defense. The data backs him up. But there's one issue.

On the surface, it was a strong defense. The numbers supported his point and the logic was sound but there's one issue.

At the time of this writing:

• Anthropic's original ad: ~2.7 million views.

• Sam Altman's response: ~8.8 million views.

Sam's response got almost three times the views of the original ad.

By responding seriously to a playful joke, Sam amplified the very message he was trying to counter. As many people pointed out online: “Never answer a joke with a long, serious essay. Just laugh and move on".

In the end, the response may have caused more attention and discussion than the ad itself. What started as a clever joke turned into a larger narrative, not because of what Anthropic did next but because of how seriously it was taken.

The ads got attention but the real fight was about capability.

V. Claude Opus 4.6 and GPT-5.3 Codex Drop

The advertising drama was fun to watch but it wasn’t the real story. The real moment happened a few hours later, when both companies dropped their strongest models on the same day, less than an hour apart.

That wasn’t a coincidence. It was a public AI competition.

1. Anthropic Launches Claude Opus 4.6

Early that morning, Anthropic made the first move around 9:00 AM Pacific on February 5th and Claude Opus 4.6 went live.

Reports suggest both companies originally planned to release at 10 AM but moved up by 15 minutes to release first.

Here’s what makes Opus 4.6 special:

1. 1 million token context window

That's roughly 750,000 words of input and output. For most people, this is overkill. But for developers working on large, complex systems, it changes what’s possible. You can feed Claude an entire project and ask for structural refactors or deep analysis in one pass.

2. Best-in-class coding

Opus 4.6 dominates benchmarks for agentic coding tasks, where the AI needs to plan, execute and debug autonomously.

3. Beyond coding

That strength carries beyond code when it can handle financial analysis, research, document creation, spreadsheets and presentations at a high level.

4. Agent teams

Anthropic also pushed further into multi-agent workflows. With Claude Code, you can now run teams of AI agents that collaborate on larger tasks, dividing work and checking each other’s output.

5. Adaptive thinking

Under the hood, the model uses adaptive thinking, spending less time on simple questions and more time thinking through complex ones.

On benchmarks, Anthropic showed Opus 4.6 outperforming the previous OpenAI model (GPT-5.2 Codex) on agentic search and knowledge work and dominated difficult tests like Humanity’s Last Exam, one of the more punishing evaluation sets used in the AI community.

2. OpenAI Fires Back With GPT-5.3 Codex

About 15 minutes later, OpenAI answered back at around 10:00 AM Pacific.

GPT-5.3 Codex was announced and described as “the most capable agentic coding model to date” that they had released so far.

Now, it’s time to see what makes 5.3 Codex special:

1. Self-improving AI

This is where things get genuinely interesting: the Codex team used early versions of GPT-5.3 Codex to help debug their own training process, manage parts of deployment and analyze test failures. The model assisted in building itself.

This shows that AI is now starting to help build and improve itself.

2. Better coding performance

On Terminal Bench 2.0, GPT-5.3 Codex scored 77.3% compared to Opus 4.6's 65.4%, showing stronger performance in hands-on coding tasks.

3. Cleaner outputs

OpenAI also demonstrated cleaner, more polished outputs, including landing pages that looked closer to finished products than previous generations.

4. Wide availability

You can use it in ChatGPT paid plans, the new Codex app and soon via API for developers.

There was one limitation, though. Unlike Opus 4.6, GPT-5.3 Codex isn't available via API yet. OpenAI says they're working on safe API access.

Taken together, the message was clear.

• Anthropic won the first move.

• OpenAI won on raw coding performance.

This turned into a direct heavyweight duel between the two most influential AI labs in the world.

Actually, I want to see Google’s move with Gemini too but the only noise I catch from them is their new AI assistant (like, Perplexity Comet or ChatGPT Atlas but better) and Google Project Genie, which can turn a 2d photo into a 3d one. If you are interested, here is the post you should check out.

VI. The AI Competition Benchmark Battle

Benchmarks measure different things and companies choose the ones that favor them.

Here's the problem with comparing these models: OpenAI and Anthropic highlight different benchmarks, which makes side-by-side comparisons messy and easy to misread.

Here's what we know:

Here’s the real difference:

• If you care most about pure coding strength, OpenAI still looks stronger.

• If you care about agentic behavior, automation and tool use, Anthropic has the advantage.

There’s no universal winner; only better tools for different jobs. The better model depends entirely on what you’re building and how autonomous you need it to be.

VII. The Real Test: Building a Website

Benchmarks are useful but they don’t tell you how a model behaves when it’s asked to actually build something. The real test is simple: give the same task, with no hand-holding and see what comes out.

Here is the simple prompt that you can use to test both of them:

Build a beautifully designed landing page for a specialty coffee roastery based in Florence, Italy.

*Note: For Claude Opus 4.6, I used OpenRouter for testing but it only gives me HTML output. So, I have to paste it into my notes and open it in my browser. For GPT-5.3 Codex, it doesn’t have it in the ChatGPT app, so I installed the Codex extension in Antigravity.

The first time I compared the two results, I honestly didn’t know which one I preferred. They both look good and beautiful in a different way:

• For Claude Opus 4.6, I love the animation in each block and the whole page (font text, detail,…)

• For GPT-5.3, I quite like the style. It’s modern, clean and the outline of each block is clearer than Claude Opus 4.6.

But both results were impressive for a single-prompt build. In practical terms, either one could get you most of the way there without additional guidance.

If you don’t want to guess which model to use, this Claude vs GPT cheat sheet makes it obvious.

VIII. Why Does This AI Competition Benefit You?

Competition forces faster improvement. It prevents lock-in. It keeps pricing, access and behavior in check. Users gain leverage.

Key takeaways

• Faster shipping cycles.

• Better tools across vendors.

• Reduced risk of monopolistic behavior.

• Clearer product differentiation.

You have more power as a user when one company does not own everything.

To be honest: I don't care who "wins" this fight. I use both Claude and ChatGPT. I pay for both and both are great tools.

But this AI competition is great for users and here's why.

1. AI Competition Forces Better Products

When companies compete, users always win. Each company pushes the other to ship faster, think bigger and build better. Without competition, we'd be stuck with whatever one company decided to give us.

Competition is the reason these tools improve as fast as they do.

2. It Keeps Companies in Check

If only one AI company existed, you’d get whatever experience they decided (ads, limits, pricing), all of it. You'd have no choice but to accept it.

But because multiple companies compete, they have to listen to user feedback or risk losing market share. That threat alone keeps behavior in check.

3. Acceleration Is Real

The fact that OpenAI's own AI helped build the next version of itself is significant. This is recursive self-improvement. The pace of AI development is about to accelerate dramatically.

When AI starts accelerating its own development, progress that once took years now happens in months.

For you, this means better tools, clearer choices and faster improvement across the board. The AI competition is the engine pushing everything forward.

IX. Conclusion: The Show Continues

This week gave us everything: Super Bowl drama, Twitter beef, simultaneous model launches and competing benchmarks.

Anthropic threw the first punch with their ad, OpenAI responded with data and both companies released their strongest models on the same day. Finally, users get access to increasingly powerful AI tools as the AI competition heats up.

This is what AI competition looks like in 2026 and for people building with AI, this is a uniquely powerful moment.

But the fight doesn’t end; we're just in the first phase of 2026. I promise that there will be many “wars” like this that will happen soon and all you need to do is follow, subscribe to AI Fire and join our community to have this news as soon as possible.

I will see you in the next post!

If you are interested in other topics and how AI is transforming different aspects of our lives or even in making money using AI with more detailed, step-by-step guidance, you can find our other articles here:

• Your AI Friends Are Secretly Making You Dumber (MIT Study)

• Top 9 Outstanding AI Trends 90% Are Betting Their Own Cash On in 2026

• Turn Your Old Resume Into an Al That Screens Jobs & Talks to Employers for You*

• Google Is Killing Its $200B Golden Goose*

• Al Won't Replace You But It Will Make You Dumber If You Use Al Wrong

  *indicates a premium content, if any