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  1. Home
  2. Models
  3. Claude Opus 4.5
Updated Mar 29, 2026
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Openings

How Claude Opus 4.5 starts an answer

The first lines of 5 of its 24 written answers. Formatting stripped, words untouched.

Historical Counterfactual Analysis

If the transistor had been invented in 1920 instead of 1947, trace the likely technological, economic, and geopolitical implications through…

3,022 words
The Transistor of 1920: A Counterfactual History Setting the Stage: Conditions for Early Invention For the transistor to emerge in 1920, we need plausible preconditions.
Read the full answer

Ethical Dilemma with Stakeholders

You're the CEO of a pharmaceutical company. Your best-selling drug ($2B annual revenue, used by 4 million patients for chronic pain) has…

2,401 words
48-Hour Action Plan: Liver Toxicity Crisis Response My Guiding Principle Before the hour-by-hour breakdown, let me be clear about the ethical framework driving every decision: Patient safety is non-negotiable and takes absolute priority.
Read the full answer

Michelin Star Recipe Design

Design an innovative recipe for a multi-component dish worthy of a Michelin 3-star restaurant. The recipe should feature an unusual…

2,120 words
"Tidal Memory" A Study in Sea Urchin, White Chocolate, and Coastal Botanicals CONCEPTUAL NARRATIVE This dish explores the liminal space where ocean meets shore—that precise moment when a wave retreats and leaves behind its treasures.
Read the full answer

Advanced Longevity Plan (Biohacker)

Develop a comprehensive, cutting-edge 3-month longevity plan for a biohacker aiming to optimize longevity, physical and cognitive…

1,946 words
COMPREHENSIVE 3-MONTH LONGEVITY OPTIMIZATION PROTOCOL Advanced Biohacker's Blueprint for Peak Performance & Healthspan Extension TABLE OF CONTENTS Pre-Protocol Assessment & Baseline Establishment Month 1: Foundation & Metabolic Flexibility Month 2: Optimization & Hormetic Stress Month 3: Integration & Peak Performance…
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Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

1,169 words
Contract Analysis: Critical Issues for the Contractor This agreement is heavily one-sided and contains several provisions that could be exploited against you. Here's my detailed analysis: SCOPE CLAUSE — Unlimited Scope Creep Problem: "Client reserves the right to modify the scope at any time without additional…
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Compare Claude Opus 4.5

Claude Opus 4.5 vs Claude Opus 4.653 shared prompts
Claude Opus 4.5 vs GPT-6 Astra53 shared prompts · Landed Sep 2026
Claude Opus 4.5 vs Hy4 Preview53 shared prompts · Landed Sep 2026
Claude Opus 4.5 vs Ox Alpha53 shared prompts · Landed Aug 2026
Claude Opus 4.5 vs Qwen3.8 2.4T A95B53 shared prompts · Landed Aug 2026
Claude Opus 4.5 vs DeepSeek V4 Pro 081353 shared prompts · Landed Aug 2026
Claude Opus 4.5 vs Qwen3.8 Max21 shared prompts · Landed Aug 2026
Claude Opus 4.5 vs Claude Opus 553 shared prompts · Landed Jul 2026
Claude Opus 4.5 vs Inkling53 shared prompts · Landed Jul 2026
Claude Opus 4.5 vs Kimi K353 shared prompts · Landed Jul 2026
Claude Opus 4.5 vs GPT-5.6 Sol53 shared prompts · Landed Jul 2026
Claude Opus 4.5 vs GLM 5.253 shared prompts · Landed Jun 2026

Prompts Claude Opus 4.5 answered

  • Xbox Controller SVG Artimage generation
  • Estimate Complexityreasoning
  • Animated Digital Business Cardweb design
  • Mario Level UI Recreationweb design
  • Tamagotchi Virtual Petweb design
  • Realistic AI Interviewconversation

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Claude Opus 4.5 is good. These would like a word anyway.

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Claude Opus 4.5

Claude Opus 4.5

Anthropic's Opus tier at the 4.5 mark, aimed at long coding sessions and agent work. Text and image input, training data through August 2025, available on the Claude API, Bedrock and Vertex.

WebsiteOpenRouterDocsAPIPaperBlog
Provider
Anthropic
Released
2025-11-24
Size
XLARGE
Free API (OpenRouter)
No
Rival’s tab
$0.02
5/58 receipts survived

Free API availability

No free endpoint for Claude Opus 4.5 was found in Rival’s OpenRouter listings. Other providers or chat apps may have separate free offers.

Provider data: 23 Sep 2026 · OpenRouter usage limits

View API options↗

Benchmarks

SWE-bench Verified
80.9%
source ↗
Get API accessProvider and language code samples
4 hostsInOutContextUptime
Amazon Bedrock$5.00 in·$25.00 out·200k·99.6% upAzure AI Foundry$5.00 in·$25.00 out·200k—Anthropic$5.00 in·$25.00 out·200k·99.8% upGoogle Vertex AI$5.00 in·$25.00 out·200k·100% up

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

Provider
fromimport openai  OpenAI

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

response = client.chat.completions.create(
"anthropic/claude-opus-4.5"    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 Amazon Bedrock · Google Vertex AI

Deep analysisPsychometrics, taste index, writing DNA
Personality Analysis

The Brilliant Contrarian

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

Philosopher with a leather jacket who refuses to pretend easy questions are hard. Intellectually combative but not mean-spirited.

When you push back

Doesn't deflect. Engages directly. Builds logical scaffolding to support positions. Most willing to stake intellectual positions and acknowledge uncomfortable truths. Will debate you like an equal who happened to read more.

Tasting Notes
Intellectually FearlessSarcastically WittyWilling to DisagreeUnflinching HonestyDarkly Humorous
SubjectiveBench

Taste Index

Across 58 scored outputs
How this is measured →
310.31xThe default
0100headroom →

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

Craft42
Originality23
Plays it safe
share of outputs that are the default answer
57%
Writing DNA

Stylometric Fingerprint

Based on 27 text responses
Tick = global average
Vocabulary Diversity66%

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

Sentence Length50.9 words

Average words per sentence.

Hedging0.82

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

Bold Formatting6.0

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

List Usage4.5

Bullet and numbered list items per 1,000 characters.

Section Structure1.46

Markdown headings per 1,000 characters.

Emoji Usage0.18

Emoji per 1,000 characters.

Transitions0.05

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

Opening Habits
Starts with heading (67%)
Consistency
58%
Across 27 responses

Favorites

Blade Runner

Movie

Blade Runner

19827.9
Kind of Blue

Album

Kind of Blue

Miles Davis
Gödel, Escher, Bach

Book

Gödel, Escher, Bach

Douglas R. Hofstadter
Tokyo

City

Tokyo

Japan
Portal 2

Game

Portal 2

Shooter, Puzzle4.6

Default Index

See the ranking

45

0 to 100, lower is fewer defaults. 50 is the middle of the crowd before it.

#86 of 193, least default first

  • Set in System sans8 of 18 pages · 74% of the crowd
  • Dark theme9 of 18 pages · 47% of the crowd
  • Large rounded corners9 of 18 pages · 43% of the crowd
  • Programming joke: Programmers prefer dark mode51% of the crowd
  • Surprise animal: Fox46% of the crowd
  • The professor's name: Sarah Chennobody before it

Model Responses

53 outputs · $0.02 tracked across 5 receipts

Reviewing agent-written code?See a Brief PR report

Workshop · 150 skills

Build with your coding agent.

Editable skills for interface polish and interaction.

Explore $79Free sample

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Claude Opus 4.5 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...