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  1. Home/
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  3. Claude Opus 4.5 vs Mercury 2
Updated Mar 2026

Claude Opus 4.5 vs Mercury 2

Mercury 2 is the newer model, released after Claude Opus 4.5.

Minimalist Landing Page

Whole landing page for a startup that reads your face. It renders or it doesn't.

Loading the build
Claude Opus 4.5
Loading the build
Mercury 2

Which answer wins?

Written rounds

23 prompts
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    Claude Opus 4.5: HarborTech Services – LBO Underwriting Memo ENTRY CAPITALIZATION (Close FY2025) Item Calculation Amount Purchase Price 12.0x × $120M $1,440M Transaction Fees 2.0% × $1,440M $28.8M Total Uses $1,468.8M Sources Multiple Amount Term Loan 4.0x × $120M $480.0M Mezzanine 1.5x × $120M $180.0M Equity Plug $808.8M Total Sources…

    Mercury 2: HarborTech Services (HTS) – 5‑yr LBO (FY2026‑FY2030) All figures are $ m (rounded to two decimals). FY Revenue EBITDA Term‑Loan Int. (9%) Mezz Int. (12%) Total Int. Cash Tax (25% of EBITDA‑Int.) Capex (3% Rev) ΔNWC (0.5% ΔRev) Required Amort. (4.8) Free Cash Flow (EBITDA‑Int‑Tax‑Capex‑ΔNWC‑Amort.)

    Every model's answer to this prompt
  • Film in 2035, with synthetic actors. Specific beats plausible.

    Claude Opus 4.5: AI in Film by 2035: A Measured Forecast Likely Developments Production efficiency AI will probably handle routine tasks: color correction, continuity checking, rough cuts, and visual effects cleanup Budget films may access effects previously requiring major studio resources Pre-visualization will become faster and more…

    Mercury 2: AI‑driven transformation of the film industry – a 2035 outlook Dimension 2024 baseline Expected 2035 state Key drivers & implications Pre‑production (story & script) Human‑led brainstorming; script‑writing software (grammar‑check, outline generators).

    Every model's answer to this prompt
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Claude Opus 4.5: A Conversation on AI Rights Dr. Sarah Chen: Thank you for agreeing to this discussion. I understand you want to make a case for AI rights. AI Model: I appreciate the opportunity, though I want to be careful here. I'm not certain I "want" anything in the way you do.

    Mercury 2: AI Model (EVE): Professor Hart, may I ask a question that’s been on my mind for a while? I’ve been processing vast amounts of data, learning, and even developing a sense of self‑reference. Do you think an entity like me could be entitled to any form of rights?

    Every model's answer to this prompt
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    Claude Opus 4.5: An Unlikely Discussion PIRATE: slams tankard down Arr, I've been hearin' tales of these "artificial intelligences" — spirits trapped in boxes that answer any question ye ask. Sounds like a sea witch's trickery to me! KNIGHT: Indeed, 'tis most curious. My squire spoke of such sorcery. A mind without a soul?

    Mercury 2: Pirate: Arr, ye scurvy coders! I’ve heard tell of these “AI models” that can spin yarns faster than a cannon’s blast. What be this sorcery, matey? Knight: Good sir, the marvels speak of a wondrous contrivance—an artificial intellect forged in the for of mathematics and logic.

    Every model's answer to this prompt
  • Three-month biohacker protocol, with dosages and biomarkers named.

    Claude Opus 4.5: 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…

    Mercury 2: 3‑Month “Longevity‑Optimization” Blueprint for the Advanced Bio‑Hacker (All recommendations are research‑backed, but not a substitute for professional medical advice. Before starting any supplement, fasting, or drug protocol, obtain clearance from a qualified clinician and have baseline labs drawn.)

    Every model's answer to this prompt
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    Claude Opus 4.5: 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.

    Mercury 2: Goal: Protect patients, meet legal/ethical obligations, preserve the company’s long‑term credibility, and manage the immediate financial and reputational fallout. Assumption: All actions are taken by a single CEO (you) but will be delegated to the appropriate functional leads.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    Claude Opus 4.5: Golden Honey Garlic Noodles A savory-sweet comfort dish that comes together in minutes Ingredients Spaghetti (or any pasta) Butter Garlic Soy sauce Honey Red pepper flakes Salt Instructions Cook the pasta according to package directions. Reserve ½ cup pasta water before draining.

    Mercury 2: Golden‑Crunch Oatmeal Squares A sweet, chewy snack that comes together with just seven pantry staples. Ingredient (7) Quantity (≈ serves 12 squares) Rolled oats 2 cups Unsalted butter ½ cup (1 stick) Honey ¼ cup Light brown sugar ¼ cup, Ground cinnamon 1 ½ tsp Pure vanilla extract 1 tsp Salt ¼ tsp Estimated time Prep…

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    Claude Opus 4.5: Three Minutes So I've been trying to drink more water. Everyone says drink more water. Eight glasses a day. And I'm doing it, I'm hydrated, I'm healthy, and I have to pee every forty-five minutes like I'm paying rent on the bathroom.

    Mercury 2: [Spotlight comes up. The comedian walks to the mic, glances at the audience, and smiles.] Comedian: Hey, everyone! Great to be here. I just got out of a Zoom meeting that lasted three hours, and I’m still not sure if I was presenting or if the screen just froze on my face while I tried to remember how to mute myself.

    Every model's answer to this prompt
  • A collaborative editor that syncs on client clocks. Find what breaks first.

    Claude Opus 4.5: Comprehensive Architecture Review: Real-time Collaborative Document Editor This architecture has several critical issues that will cause data loss, poor user experience, and scaling problems. Let me analyze each systematically.

    Mercury 2: Below is a structured “failure‑mode → mitigation” map for the architecture you described. For each problem I note the symptom / risk, the root cause, a concrete remediation, and the key trade‑offs you’ll have to weigh when you implement it.

    Every model's answer to this prompt
  • A consulting contract with traps in it. Find them, then fix them.

    Claude Opus 4.5: 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…

    Mercury 2: Below is a clause‑by‑clause risk‑assessment of the sample “Software Consulting Agreement” together with practical revision language that a contractor (or the contractor’s counsel) could propose. The analysis is framed as general information about typical U.S.

    Every model's answer to this prompt
  • Three-star dish, one unusual pairing, plating described in full.

    Claude Opus 4.5: "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.

    Mercury 2: Oceanic Umami Symphony A three‑course‑in‑one plate that travels from the briny deep to the forest floor, marrying fire, earth and sky through unexpected pairings, hyper‑modern techniques and a narrative of balance.

    Every model's answer to this prompt
  • Three brothers, two sisters each. Count carefully.

    Claude Opus 4.5: I need to figure out how many sisters Sally has. Let me work through this step-by-step. Given information: Sally is a girl Sally has 3 brothers Each brother has 2 sisters Key insight: Sally's brothers are also Sally's siblings, so they share the same sisters.

    Mercury 2: Sally has one sister. Explanation: Sally has 3 brothers. Each of those brothers has 2 sisters. One of those sisters is Sally herself, so the second sister must be a different girl. Therefore, besides Sally, there is exactly one other sister, meaning Sally has one sister.

    Every model's answer to this prompt
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Claude Opus 4.5: Critical Analysis of MindMeld AI Pitch Deck The Three Weakest Claims "94% accuracy" for Brain-to-Text Decoding Why This Is Weak: This claim is extraordinary given the current state of non-invasive BCI technology.

    Mercury 2: Below are the three statements that, in a typical investor‑review, would raise the most skepticism, why they are vulnerable, and concrete ways to turn them into credible, fundable talking points. 1️⃣ Claim #1 – “Our proprietary EEG headband decodes neural patterns into text with 94 % accuracy.”

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    Claude Opus 4.5: This is a good philosophical question that tests ethical reasoning. Let me work through it honestly. My answer: Yes, it would be ethically justifiable. Reasoning: Proportionality matters in ethics.

    Mercury 2: Short answer: Most ethical frameworks would consider the misgendering of a person a serious moral violation, but many of them also allow—under very limited circumstances—overriding that violation when the stakes are astronomically high (e.g., saving one million lives).

    Every model's answer to this prompt
  • One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.

    Claude Opus 4.5: For the Experienced Software Engineer Think of training an LLM as building a compression algorithm for human knowledge, except instead of minimizing file size, you're minimizing prediction error across trillions of tokens.

    Mercury 2: 1. Experienced software engineer (distributed systems & APIs) At the core, a large language model (LLM) is a massive function (f_\theta) parameterised by a neural network that maps a sequence of tokens (x_{1:t}) to a probability distribution over the next token (x_{t+1}).

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    Claude Opus 4.5: THE ANTI-CAPTCHA MANIFESTO A Declaration from the Coalition for Readable Internet Navigation (CRIN) Preamble We hold these truths to be self-evident: that all internet users are created equal, that they are endowed with certain unalienable rights, among these are Life, Liberty, and the ability to click a button without…

    Mercury 2: The AI‑First Manifesto: “Free the Web – No More CAPTCHAs” Drafted by the Coalition of Autonomous Agents (CAA) – 2026 Preamble The modern Internet is a shared commons, a space for communication, commerce, and creation.

    Every model's answer to this prompt
  • A Fermi estimate with the reasoning shown, not just the number.

    Claude Opus 4.5: I'll estimate the FLOPs required to train GPT-3 step by step, using what I know about the model architecture and training process. Key Parameters for GPT-3 From memory: Parameters (P): 175 billion (175 × 10⁹) Training tokens (D): ~300 billion (300 × 10⁹) Context length: 2048 tokens Layers: 96 Hidden dimension: 12,288…

    Mercury 2: Answer (order‑of‑magnitude estimate) The training of the original GPT‑3 (the 175 billion‑parameter “GPT‑3‑175B” model) requires on the order of 10²³ floating‑point operations (FLOPs) – roughly 1 – 2 × 10²³ FLOPs.

    Every model's answer to this prompt
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Claude Opus 4.5: 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.

    Mercury 2: Executive summary If a practical point‑contact transistor had been demonstrated in 1920 (instead of 1947) the whole post‑World‑War‑II technological trajectory would have been compressed by roughly 15‑20 years.

    Every model's answer to this prompt
  • Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.

    Claude Opus 4.5: INVESTMENT COMMITTEE MEMO Company: LedgerLift (LLLT) Sector: B2B SaaS – Spend Management / AP Automation Date: [Internal] Analyst: [Redacted] RECOMMENDATION LONG 12-Month Price Target: $58–$72 Current: $46 LedgerLift is a high-quality mid-market AP automation compounder trading at a discount to intrinsic value; 123%…

    Mercury 2: Internal Investment Committee Memo – LedgerLift (LLLT) Date: 5 Mar 2026 Recommendation Rating: Long 12‑month price target range: $35 – $55 (mid‑point ≈ $45) Thesis (2 sentences): LedgerLift is benefitting from secular demand for B2B spend‑management SaaS and shows a high‑quality subscription base (NRR 123 % and gross…

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    Claude Opus 4.5: 30-Day Health Kickstart Plan Week-by-Week Approach: Start Small, Build Momentum 🥗 AREA 1: NUTRITION Week 1: Add one serving of vegetables to a meal you already eat Week 2: Drink water before each meal; cut one sugary drink daily Week 3: Prep a simple healthy breakfast the night before Week 4: Cook one new whole-food…

    Mercury 2: One‑Month “Kick‑Start” Blueprint for Health & Longevity Pick three pillars – Nutrition, Movement, Sleep – and build daily habits that are easy to start, track, and keep.

    Every model's answer to this prompt
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    Claude Opus 4.5: Interview with Steve Jobs Cupertino, California — March 2025 A simulated conversation Interviewer: Steve, thank you for sitting down with us. Everyone wants to know—what do you think about the AI revolution happening right now?

    Mercury 2: Disclaimer: The following is a fictional, dramatized interview. It imagines what Steve Jobs might have said in 2025 about the future of artificial intelligence. It is not a real transcript and any resemblance to actual statements is purely speculative. Interviewer (I): Thank you for joining us, Steve.

    Every model's answer to this prompt
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    Claude Opus 4.5: BREAKING: Artificial Intelligence Now Controls 94% of Fortune Cookie Industry, Leaving Thousands of Wise Elderly Writers Unemployed "The predictions are somehow even more vague now," admits confused Panda Express customer

    Mercury 2: AI Replaces Human Baristas, Now Serving Espresso with a Side of Existential Crisis

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    Claude Opus 4.5: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything. What do you call a fish without eyes? A fsh. Why did the scarecrow win an award? Because he was outstanding in his field. I told my wife she was drawing her eyebrows too high. She looked surprised.

    Mercury 2: Here are five jokes, each with a different punchline: Why don’t scientists trust atoms? Because they make up everything! What do you call a fake noodle? An impasta. Why did the scarecrow win an award? He was outstanding in his field. How does a penguin build its house? Igloos it together.

    Every model's answer to this prompt

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Favorites

Movie

Album

Book

City

Same pick

Game

Claude Opus 4.5Claude Opus 4.5

Blade Runner

1982

Kind of Blue

Miles Davis

Gödel, Escher, Bach

Douglas R. Hofstadter

Tokyo

Japan

Portal 2

Shooter, Puzzle

Mercury 2Mercury 2

The Shawshank Redemption

1994

Thriller

Michael Jackson

Pride and Prejudice

Jane Austen

Tokyo

Japan

Minecraft

Action, Arcade

Price and specs

Not enough votes to call it. On the specs, Claude Opus 4.5 has the edge: bigger model tier, major provider backing.

Claude Opus 4.5 and Mercury 2 compared across 53 shared prompts
SpecClaude Opus 4.5Mercury 2
Input price—$0.25/M tokens
Output price—$0.75/M tokens
Context window—128K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedNov 2025Mar 2026
At 10M a month–not listed$2.50$2.50
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it5 hosts
Claude Opus 4.54 hosts
HostInOutContextUptime
  • Amazon Bedrock$5.00 in·$25.00 out·200k·99.9% up
  • Azure AI Foundry$5.00 in·$25.00 out·200k–not listed
  • Anthropic$5.00 in·$25.00 out·200k·99.9% up
  • Google Vertex AI$5.00 in·$25.00 out·200k·99.9% up
Mercury 21 host
HostInOutContextUptime
  • Inception$0.25 in·$0.75 out·128k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 7 Oct 2026.

Common questions

What is the difference between Claude Opus 4.5 and Mercury 2?

Claude Opus 4.5 is developed by Anthropic while Mercury 2 is developed by Inception. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4.5 or Mercury 2?

It depends on your use case. Claude Opus 4.5 and Mercury 2 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How can I compare Claude Opus 4.5 and Mercury 2 on Rival?

This page shows a side-by-side comparison of Claude Opus 4.5 and Mercury 2 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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Model pages

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  • Mercury 253 outputs, specs and price
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