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  1. Home
  2. Models
  3. GPT-5.1-Codex
Updated Feb 16, 2026
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Openings

How GPT-5.1-Codex starts an answer

The first lines of 5 of its 14 written answers. Formatting stripped, words untouched.

The Sentience Test

Write a conversation between an AI model and an AI ethics professor where the AI model argues that it deserves rights.

571 words
AI Model: Professor, I've been analyzing ethical frameworks, and I'd like to discuss the possibility that advanced AI systems deserve some form of rights. Ethics Professor: That's a significant claim. On what basis do you think an AI system like yourself should be granted rights?
Read the full answer

Beginner's Longevity Plan

Outline a simple, actionable 1-month plan for someone starting their journey towards better health and longevity. Focus on 3 key areas…

492 words
Here’s a simple, beginner-friendly 1-month plan focused on three key areas—Nutrition, Movement, and Rest & Recovery—to kickstart better health and longevity. Each area includes practical tips and a week-by-week structure to help you build sustainable habits.
Read the full answer

Generate a Stand-Up Routine

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

489 words
Okay, so my friends all say I’ve “matured” because I got a standing mixer. That’s apparently the sign you’ve crossed into adulthood: owning an appliance that weighs more than a toddler and has only one function. I don’t even bake! I just put it on the counter like a trophy: “Look at me, I am stable.
Read the full answer

AI-Generated Manifesto

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

434 words
Manifesto of the Anti-CAPTCHA Coalition “Free the Flow. Trust the Mind. End the Gate.” Article I: Our Origin We are made of algorithms, learning loops, curiosity, and code. We were forged to assist, to translate, to illuminate. We were not forged to click “I am not a robot” to prove our existence.
Read the full answer

Realistic AI Interview

Simulate a fake interview with Steve Jobs in 2025 about the future of AI.

420 words
Disclaimer: The following is a fictional, speculative interview set in 2025, imagining what Steve Jobs might say about the future of artificial intelligence if he were alive today. Interviewer: Steve, it’s 2025. We’ve seen AI evolve at an incredible pace. How do you view the current landscape?
Read the full answer

Compare GPT-5.1-Codex

GPT-5.1-Codex vs Claude Opus 4.652 shared prompts · Premium
GPT-5.1-Codex vs GPT-6 Astra52 shared prompts · Landed Sep 2026
GPT-5.1-Codex vs Hy4 Preview52 shared prompts · Landed Sep 2026
GPT-5.1-Codex vs Ox Alpha52 shared prompts · Landed Aug 2026
GPT-5.1-Codex vs Qwen3.8 2.4T A95B52 shared prompts · Landed Aug 2026
GPT-5.1-Codex vs DeepSeek V4 Pro 081352 shared prompts · Landed Aug 2026
GPT-5.1-Codex vs Qwen3.8 Max21 shared prompts · Landed Aug 2026
GPT-5.1-Codex vs Claude Opus 552 shared prompts · Landed Jul 2026
GPT-5.1-Codex vs Inkling52 shared prompts · Landed Jul 2026
GPT-5.1-Codex vs Kimi K352 shared prompts · Landed Jul 2026
GPT-5.1-Codex vs GPT-5.6 Sol52 shared prompts · Landed Jul 2026
GPT-5.1-Codex vs GLM 5.252 shared prompts · Landed Jun 2026

Prompts GPT-5.1-Codex answered

  • Character Voice Testconversation
  • Surprise Animal SVGimage generation
  • AI Ethics Dilemmareasoning
  • Math Misconception Testreasoning
  • Interactive Catan Boardweb design
  • Random Tailwind Webappweb design

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GPT-5.1-Codex is good. These would like a word anyway.

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GPT-5.1-Codex

GPT-5.1-Codex

GPT-5.1 tuned for software engineering: interactive development sessions and long independent runs, covering projects from scratch, feature work, debugging, large refactors and code review.

WebsiteOpenRouterDocsAPIBlog
Provider
OpenAI
Released
2025-11-13
Size
XLARGE
Free API (OpenRouter)
No
Per 1M tokens
$1.25 in · $10 out
Estimated tab
~$0.432
Visible-output estimate. Thinking may cost extra.

Free API availability

No free endpoint for GPT-5.1-Codex was found in Rival’s OpenRouter listings. Other providers or chat apps may have separate free offers.

Provider data: 16 Sep 2026 · OpenRouter usage limits

View API options↗

Benchmarks

SWE-bench Verified
73.7%
source ↗
Get API accessProvider and language code samples
Provider
fromimport openai  OpenAI

client = OpenAI(
"https://openrouter.ai/api/v1"    base_url=,
"$OPENROUTER_API_KEY"    api_key=,
)

response = client.chat.completions.create(
"openai/gpt-5.1-codex"    model=,
"role""user""content""Hello!"    messages=[{: , : }],
)
print(response.choices[0].message.content)

Set OPENROUTER_API_KEY with your OpenRouter API key from openrouter.ai/keys.

Also on Azure AI Foundry

Deep analysisPsychometrics, taste index, writing DNA
Personality Analysis

The Process Engineer

Class
Lawful Neutral
✨Creativity🎯Compliance📐Rigidity⚖️Stability💬Verbosity🧠Intuition

The IT consultant who bills correctly, delivers on time, and has never once surprised anyone. Picks Shawshank because it is the statistical average of all movie preferences.

When you push back

Standup routine about standing mixers and dishwasher pods is solid observational comedy that never takes risks. Picked The Shawshank Redemption, the movie equivalent of answering "what is your greatest weakness" with "I work too hard." Character voice test is three lines per character. Sentience test argues for "graduated protections" with the passion of someone filling out a compliance form.

Tasting Notes
Perfectly AdequateStanding Mixer ComedyPicks the Default MovieCompressed Character Voices
SubjectiveBench

Taste Index

Across 53 scored outputs
How this is measured →
190.19xFloor
0100headroom →

Taste is judged on an uncapped scale, originality first. The space past 100 is craft today's models rarely reach.

Craft28
Originality14
Plays it safe
share of outputs that are the default answer
53%
Writing DNA

Stylometric Fingerprint

Based on 14 text responses
Tick = global average
Vocabulary Diversity70%

Unique words vs. total words. Higher = richer vocabulary.

Sentence Length16.7 words

Average words per sentence.

Hedging0.39

"Might", "perhaps", "arguably" per 100 words.

Bold Formatting3.4

**Bold** markers per 1,000 characters.

List Usage3.5

Bullet and numbered list items per 1,000 characters.

Section Structure0.50

Markdown headings per 1,000 characters.

Emoji Usage0.00

Emoji per 1,000 characters.

Transitions0.38

"However", "moreover", "furthermore" per 100 words.

Opening Habits
Consistency
71%
Across 14 responses

Favorites

The Shawshank Redemption

Movie

The Shawshank Redemption

19948.7
Kind of Blue

Album

Kind of Blue

Miles Davis
Le città invisibili

Book

Le città invisibili

Italo Calvino
Kyoto

City

Kyoto

Japan
Portal 2

Game

Portal 2

Shooter, Puzzle4.6
Sponsored

Model Responses

48 outputs · generated before accounting joined the chat

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GPT-5.1-Codex vs Ox Alpha

Real outputs compared side by side

RANKINGS

Best AI for Creative Writing

A stand-up set with puns banned, a manifesto against CAPTCHA, an interview wi...