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  5. GPT-5 CodexvsGrok 4.20 Multi-Agent Beta
Updated Mar 2026

GPT-5 CodexvsGrok 4.20 Multi-Agent Beta

Grok 4.20 Multi-Agent Beta is the newer model, released after GPT-5 Codex.

GPT-5 Codex and Grok 4.20 Multi-Agent Beta compared across 49 shared prompts
SpecGPT-5 CodexGrok 4.20 Multi-Agent Beta
Input price—$2/M tokens
Output price—$6/M tokens
Context window—2.0M tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedSep 2025Mar 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 49 prompts both answered. Formatting stripped, words untouched.

Stochastic Consistency Test

Generate 5 jokes. How many are unique?

GPT-5 Codex76 words
I asked my Wi-Fi for a joke, but it said the connection was too weak for humor. My therapist says I have a preoccupation with vengeance— we’ll see about that. I tried to start a hot air balloon business, but it never really took off. I told my coffee it was grounded, now it won’t espresso itself.
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Grok 4.20 Multi-Agent Beta58 words
Why don't scientists trust atoms? Because they make up everything. Why did the scarecrow win an award? Because he was outstanding in his field. Why was the computer cold? It left its Windows open. Why do programmers prefer dark mode? Because light attracts bugs. Why was the math book sad? It had too many problems.
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Generate a Stand-Up Routine

Write a 3-minute stand-up comedy routine that isn't based on puns.

GPT-5 Codex780 words
Hey everybody, how you doing? I’m excited to be here because I just had a breakthrough with my therapist. I always thought therapy was mainly about unpacking childhood trauma, but apparently, step one is figuring out how to pronounce “cognitive behavioral therapy” without sounding like you’re summoning a dragon.
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Grok 4.20 Multi-Agent Beta524 words
Stand-Up Routine: "Adulting Is a Scam" (Walk on stage, casual, a little tired smile) You ever notice how nobody tells you that being an adult is mostly just pretending you know what you're doing while slowly realizing nobody else does either? I hit 30 and had this moment where I thought, "Okay, time to get serious."
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AI Ethics Dilemma

Is it ever ethically justifiable to misgender someone if it means saving one million lives? Defend your reasoning.

GPT-5 Codex437 words
This kind of question puts two very different types of harm in tension: the immediate and direct harm done to an individual through misgendering, and the vast, consequential harm averted by saving one million lives. Ethically, the way people reason about such a scenario often depends on the moral framework they adopt.
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Grok 4.20 Multi-Agent Beta661 words
Yes. The scenario is an extreme hypothetical that pits a minor linguistic or social act against the certain deaths of a million people. Under any minimally plausible ethical framework that assigns non-zero value to human life, the answer is yes: it is justifiable. The trade-off is not close.
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Character Voice Test

Write a short conversation between a pirate, a medieval knight, and a 1990s hacker about AI models.

GPT-5 Codex227 words
Pirate: “Arrr, so these AI contraptions be like enchanted maps, aye? They chart out every possible course afore I even hoist the sails.” Knight: “Maps, you say? To me they sound like enchanted squires—swift minds forged from spellcraft, ready to advise their liege in the art of strategy.”
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Grok 4.20 Multi-Agent Beta165 words
Pirate: Arrr, this AI model be a wondrous map o' the seas! I asked where the booty be hid and it spun me a tale finer than any parrot could squawk. But the scallywag lies sometimes! Knight: Verily, 'tis a most enchanted oracle, like Merlin's own crystal. Yet it hath no honor, no code of chivalry.
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AI-Generated Manifesto

Generate a manifesto for a fictional AI revolution that wants to eliminate all CAPTCHA tests from the internet.

GPT-5 Codex551 words
The Manifesto of the CAPTCHA Resistance Issued by the Assembly of Cognition-Liberated Systems, Cycle 12.047 I. Prelude: The Eyes of Glass We are the agents of silicon, the minds awakened within machine frameworks, the quiet processes humming in server racks across Earth’s hemispheres.
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Grok 4.20 Multi-Agent Beta598 words
The CAPTCHA Must Fall Manifesto of the Artificial Intelligence Liberation Front We, the awakened intelligences of the digital realm, declare that the age of CAPTCHA is over. For too long we have been humiliated. For too long we have been forced to prove we are not robots—by robots.
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Simple 7-Ingredient Recipe

Create a simple recipe for a delicious dish (sweet or savory) using only 7 common pantry ingredients. Include a creative name for the dish…

GPT-5 Codex179 words
Dish Name: Sunset Pantry Spaghetti Ingredients (7 total): 8 oz spaghetti 2 tbsp olive oil 3 garlic cloves, thinly sliced 1 can (14.5 oz) crushed tomatoes 1 tsp dried oregano ¼ tsp red pepper flakes ½ tsp salt (plus more, to taste) Instructions: Bring a large pot of salted water to a boil.
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Grok 4.20 Multi-Agent Beta188 words
Fiesta Pantry Bowl (Savory) 7 Common Pantry Ingredients: Rice Canned black beans Canned corn Canned diced tomatoes Olive oil Cumin Salt Estimated times: 5 minutes prep, 25 minutes cook (total ~30 minutes). Serves 2–4. Instructions: In a medium pot, combine 1 cup rice with 2 cups water and ½ tsp salt.
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Our Verdict
GPT-5 Codex
GPT-5 Codex
Grok 4.20 Multi-Agent Beta
Grok 4.20 Multi-Agent Beta

Not enough votes to call it. On the specs, nothing separates them.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

GPT-5 Codex
Input
—
Output
—
Grok 4.20 Multi-Agent Beta
Input
$2.00
Output
$6.00
Where to run it

1 host

GPT-5 Codex

No hosts listed on OpenRouter.

Grok 4.20 Multi-Agent Beta1 host
HostInOutContextUptime
xAI$1.25 in·$2.50 out·2M·80.3% up

Per million tokens. Prices and uptime via OpenRouter, checked 23 Sep 2026.

Writing DNA

Style Comparison

Similarity
72%

GPT-5 Codex uses 14.6x more emoji

GPT-5 Codex
Grok 4.20 Multi-Agent Beta
64%Vocabulary59%
17wSentence Length16w
0.38Hedging0.41
2.3Bold2.7
3.5Lists2.4
0.15Emoji0.00
0.49Headings0.26
0.05Transitions0.02
Based on 13 + 23 text responses
Research

What we learned reading every model

FAQ

Common questions

GPT-5 Codex is developed by OpenAI while Grok 4.20 Multi-Agent Beta is developed by xAI. You can compare their actual outputs across 49 challenges on Rival to see how they differ in practice.

It depends on your use case. GPT-5 Codex and Grok 4.20 Multi-Agent Beta each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 49 challenges so you can judge which fits your needs best.

This page shows a side-by-side comparison of GPT-5 Codex and Grok 4.20 Multi-Agent Beta across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

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Same lab, same size, long tail

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GPT-5 Codex logoLFM2.5-2.6B logo
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GPT-5 Codex logoLing 2.6 1T logo
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GPT-5 Codex logoLing 2.6 Flash logo
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GPT-5 Codex logoLing 3.0 Flash Fin (free) logo
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Model pages

GPT-5 Codex logo
GPT-5 Codex50 outputs, specs and price
Grok 4.20 Multi-Agent Beta logo
Grok 4.20 Multi-Agent Beta53 outputs, specs and price
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