Claude Opus 4.6 vs OpenAI Codex 5.3: Which is Higher?

The rivalry between Anthropic and OpenAI has intensified, from competing Tremendous Bowl adverts to launching new coding fashions on the identical day. Anthropic’s Claude Opus 4.6 and OpenAI’s Codex 5.3 at the moment are reside. Each present robust benchmarks, however which one actually stands out? I’ll put them to the check and examine their efficiency on the identical activity. Let’s see which one comes out on high.

OpenAI Codex 5.3 vs Claude Opus 4.6: Benchmarks

Claude 4.6 Opus scores for SWE-Bench and Cybersecurity are described as “industry-leading” or “high of the chart” of their launch notes, with particular high-tier efficiency indicated of their system playing cards.

Claude 4.6 Opus (Anthropic):

• Focus: Distinctive at deep reasoning and long-context retrieval (1M tokens). It excels at Terminal-Bench 2.0, suggesting it’s at present the strongest mannequin for agentic planning and complicated system-level duties.
• New Options: Introduces “Adaptive Pondering” and “Context Compaction” to handle long-running duties with out shedding focus.

Right here’s our detailed overview on Claude Opus 4.6.

GPT-5.3-Codex (OpenAI):

• Focus: Specialised for the complete software program lifecycle and visible pc use. It exhibits a large leap in OSWorld-Verified, making it extremely efficient at navigating UI/UX to finish duties.
• New Options: Optimized for velocity (25% quicker than 5.2) and “Interactive Collaboration,” permitting customers to steer the mannequin in real-time whereas it executes.

Right here’s our detailed weblog on Codex 5.3.

How one can Entry?

• For Opus 4.6: I’ve used my Claude Professional account value $17 per 30 days.
• For Codex 5.3: I’ve used the macOS app of codex and my ChatGPT plus account (₹1,999/month) for logging-in.

Claude Opus 4.6 vs OpenAI Codex 5.3 Duties

Now that we’re achieved with all the idea, let’s examine the efficiency of those fashions. You could find my immediate, mannequin responses and my tackle the identical:

Job 1: Twitter‑type Clone (net app)

Immediate:

You’re an skilled full‑stack engineer and product designer. Your activity is to construct a easy Twitter‑type clone (net app) utilizing dummy frontend knowledge.

Use: Subsequent.js (App Router) + React + TypeScript + Tailwind CSS. No authentication, no actual backend; simply mocked in‑reminiscence knowledge within the frontend.

Core Necessities:

• Left Sidebar: Brand, essential nav (House, Discover, Notifications, Messages, Bookmarks, Lists, Profile, Extra), main “Publish” button.
• Heart Feed: Timeline with tweets, composer on the high (profile avatar + “What is going on?” enter), every tweet with avatar, title, deal with, time, textual content, optionally available picture, and actions (Reply, Retweet, Like, View/Share).
• Proper Sidebar: Search bar, “Developments for you” field (matters with tweet counts), “Who to observe” card (3 dummy profiles).
• Prime Navigation Bar: Mounted with “House” and a pair of tabs: “For you” and “Following”.
• Cell Habits: On small screens, present a backside nav bar with icons as an alternative of the left sidebar.

Dummy Knowledge:

• Create TypeScript sorts for Tweet, Consumer, Development.
• Seed app with:
  • 15 dummy tweets (brief/lengthy textual content, some with photographs, various like/retweet/reply counts).
  • 5 dummy tendencies (title, class, tweet depend).
  • 5 dummy customers for “Who to observe”.

Habits:

• Publish Composer: Sort a tweet and immediately add it to the highest of the “For you” feed.
• Like Button: Toggle appreciated/unliked state and replace like depend.
• Tabs: “For you” exhibits all tweets, “Following” exhibits tweets from 2–3 particular customers.
• Search Bar: Filter tendencies by title because the consumer sorts.

File and Element Construction:

• app/structure.tsx: World structure.
• app/web page.tsx: Primary feed web page.
• parts/Sidebar.tsx: Left sidebar.
• parts/Feed.tsx: Heart feed.
• parts/Tweet.tsx: Particular person tweet playing cards.
• parts/TweetComposer.tsx: Composer.
• parts/RightSidebar.tsx: Developments + who-to-follow.
• parts/BottomNav.tsx: Cell backside navigation.
• knowledge/knowledge.ts: Dummy knowledge and TypeScript sorts.

Use Tailwind CSS to match Twitter’s design: darkish textual content on mild background, rounded playing cards, refined dividers.

Output:

• Present a brief overview (5–7 bullet factors) of the structure and knowledge move.
• Output all recordsdata with feedback on the high for file paths and full, copy-paste-ready code.
• Match imports with file paths used.

Constraints:

• No backend, database, or exterior API—all the things should run with npm run dev.
• Use a regular create-next-app + Tailwind setup.
• Maintain all content material dummy (no actual usernames or copyrighted content material).

How one can Run:

After making a Subsequent.js + Tailwind venture, run the app with the precise instructions offered.

Output:

My Take:

The Twitter clone constructed by Claude was noticeably higher. Codex did handle to create a sidebar panel, nevertheless it had lacking photographs and felt incomplete, whereas Claude’s model seemed way more polished and production-ready.

Job 2: Making a Blackjack Sport

Immediate:

Sport Overview:

Construct a easy, truthful 1v1 Blackjack recreation the place a human participant competes in opposition to a pc vendor, following normal on line casino guidelines. The pc ought to observe fastened vendor guidelines and never cheat or peek at hidden data.

Tech & Construction:

• Use HTML, CSS, and JavaScript solely.
• Single-page app with three recordsdata: index.html, type.css, script.js.
• No exterior libraries.

Sport Guidelines (Customary Blackjack):

• Deck: 52 playing cards, 4 fits, values:
  • Quantity playing cards: face worth.
  • J, Q, Ok: worth 10.
  • Aces: worth 1 or 11, whichever is extra favorable with out busting.
• Preliminary Deal:
  • Participant: 2 playing cards face up.
  • Supplier: 2 playing cards, one face up, one face down.
• Participant Flip:
  • Choices: “Hit” (take card) or “Stand” (finish flip).
  • If the participant goes over 21, they bust and lose instantly.
• Supplier Flip (Mounted Logic):
  • Reveal the hidden card.
  • Supplier should hit till 17 or extra, and should stand at 17 or above (select “hit on mushy 17” or “stand on all 17s” and state it clearly within the UI).
  • Supplier doesn’t see future playing cards or override guidelines.
• Final result:
  • If the vendor busts and the participant doesn’t, the participant wins.
  • If neither busts, the upper complete wins.
  • Equal totals = “Push” (tie).

Equity / No Bias Necessities:

• Use a correctly shuffled deck at first of every spherical (e.g., Fisher-Yates shuffle).
• The vendor should not change conduct based mostly on hidden data.
• Don’t rearrange the deck mid-round.
• Maintain all recreation logic in script.js for audibility.
• Show a message like: “Supplier follows fastened guidelines (hits till 17, stands at 17+). No rigging.”

UI Necessities:

• Format:
  • Prime: Supplier part – present vendor’s playing cards and complete.
  • Center: Standing textual content (e.g., “Your flip – Hit or Stand?”, “Supplier is drawing…”, “You win!”, “Supplier wins”, “Push”).
  • Backside: Participant part – present participant’s playing cards, complete, and buttons for Hit, Stand, and New Spherical.
  • Present playing cards as easy rectangles with rank and go well with (textual content solely, no photographs).
  • Show win/loss/tie counters.

Interactions & Move:

• When the web page hundreds, present a “Begin Sport” button, then deal preliminary playing cards.
• Allow Hit/Stand buttons solely in the course of the participant’s flip.
• After the participant stands or busts, run the vendor’s computerized flip step-by-step (with small timeouts).
• At spherical finish, present the result message and replace counters.
• “New Spherical” button resets palms and reshuffles the deck.

Code Group:

• Features in script.js:
  • createDeck(): Returns a contemporary 52-card deck.
  • shuffleDeck(deck): Shuffles the deck (Fisher-Yates).
  • dealInitialHands(): Offers 2 playing cards every.
  • calculateHandTotal(hand): Handles Aces as 1 or 11 optimally.
  • playerHit(), playerStand(), dealerTurn(), checkOutcome().
• Observe variables for playerHand, dealerHand, deck, and win/loss/tie counters.

Output Format:

• Briefly clarify in 5–7 bullet factors how equity and no bias are ensured.
• Output the complete content material for:
  • index.html
  • type.css
  • script.js
• Make sure the code is copy-paste prepared and constant (no lacking features or variables).
• Add a “How one can run” part: instruct to put the three recordsdata in a folder and open index.html in a browser.

Output:

My Take:

The hole turned much more apparent within the Blackjack recreation. Codex 5.3 produced a really boring, static output. In distinction, Claude Opus 4.6 was approach forward. It delivered a correct inexperienced on line casino mat, a way more engaging UI, and an total participating net expertise. 

Claude Opus 4.6 vs OpenAI Codex 5.3: Closing Verdict

Opinions on whether or not Codex 5.3 or Opus 4.6 is best stay divided within the tech neighborhood. Codex 5.3 is favored for its velocity, reliability in producing bug-free code, and effectiveness in complicated engineering duties, significantly for backend fixes and autonomous execution. Alternatively, Opus 4.6 excels in deeper reasoning, agentic capabilities, and dealing with long-context issues, providing extra engaging UI designs. Nonetheless, it might probably face challenges with iterations and token effectivity.

After my hands-on expertise with each fashions, for this battle, Codex 5.3 vs Claude Opus 4.6, I’m going with Claude Opus 4.6 🏆. 

The general efficiency, ease of use, and polished UI made it stand out within the duties I examined, despite the fact that Codex 5.3 had its deserves in velocity and performance.

Don’t simply take my phrase for it. Put each fashions to the check your self and see which one works finest for you! Let me know your ideas.