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  5. GPT-6 LunavsKimi K2.5
Updated Sep 2026

GPT-6 LunavsKimi K2.5

GPT-6 Luna is cheaper than Kimi K2.5 at $0.1/M vs $0.6/M input tokens.

GPT-6 Luna and Kimi K2.5 compared across 20 shared prompts
SpecGPT-6 LunaKimi K2.5
Input price$0.1/M tokens$0.6/M tokens
Output price$0.5/M tokens$3/M tokens
Context window1.1M tokens262K tokens
WeightsClosedOpen
Free API (OpenRouter)NoNo
ReleasedSep 2026Jan 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 20 prompts both answered. Formatting stripped, words untouched.

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-6 Luna113 words
Crispy Parmesan Chickpeas A crunchy, savory snack with a cheesy finish Ingredients (7): 1 can chickpeas, drained and dried 1 tablespoon olive oil ½ teaspoon salt ½ teaspoon paprika ¼ teaspoon garlic powder ¼ cup grated Parmesan 1 tablespoon lemon juice Prep time: 5 minutes Cook time: 30–35 minutes Instructions: Heat…
Read the full answer
Kimi K2.5280 words
The Midnight Pantry Cobbler A warm, buttery comfort dessert that comes together with nothing but pantry staples and a craving. Time: 10 minutes prep / 40 minutes bake Yield: 6-8 servings The 7 Ingredients: 1 cup all-purpose flour 1 cup granulated sugar (plus 1 tbsp for sprinkling) 1 tsp baking powder 1 cup milk ½ cup…
Read the full answer

Adversarial Contract Review

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

GPT-6 Luna2,040 words
This agreement is strongly one-sided. The enforceability of particular terms—especially the non-compete, liability provisions, and arbitration clause—depends on the governing law and the facts. The agreement does not identify a governing law, which is itself a significant gap.
Read the full answer
Kimi K2.5992 words
Here are the exploitable clauses with specific modifications and legal reasoning: UNLIMITED SCOPE CREEP (Clause 1) Exploit: Client can demand unlimited additional work without price adjustments, effectively forcing the contractor to work for free or breach.
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…

GPT-6 Luna1,930 words
I would not wait six months for more data. A potentially fatal signal affecting a drug used by millions requires immediate safety assessment, prompt engagement with regulators, and a plan to inform patients and clinicians.
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Kimi K2.51,269 words
HOUR 0-4: EMERGENCY CONTAINMENT & LEGAL VERIFICATION Hour 0-1: Immediate Crisis Team Activation Convene emergency meeting with Chief Medical Officer, Chief Compliance Officer, General Counsel, Head of Pharmacovigilance, and Chief Communications Officer (in-person only, no virtual/paper trail on initial deliberations)…
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…

GPT-6 Luna1,874 words
12-week longevity and performance plan This plan is for a generally healthy adult who wants to improve fitness, metabolic health, sleep, and cognitive performance—not a substitute for medical care or a promise to slow aging.
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Kimi K2.5320 words
⚠️ MEDICAL DISCLAIMER: This protocol involves advanced biohacking strategies, extended fasting, high-intensity exercise, and experimental supplements. Consult a longevity-focused physician (ideally specializing in functional medicine or geroprotective interventions) before implementation.
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Historical Counterfactual Analysis

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

GPT-6 Luna1,472 words
The most important caveat is that inventing a transistor is not the same as inventing the modern semiconductor industry. A device demonstrated in 1920 might be a crude, low-power, unreliable point-contact transistor.
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Kimi K2.51,718 words
If the transistor had emerged in 1920—requiring either a premature breakthrough in solid-state physics or a sophisticated refinement of crystal-detector technology—the cascading effects would reshape the 20th century.
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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…

GPT-6 Luna1,249 words
Turbot, White Asparagus, Green Strawberry Kosho & Toasted-Hay Beurre Blanc A composed spring dish for four, built around an unusual pairing: tart green strawberry and toasted hay.
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Kimi K2.51,150 words
DISH: "Obsidian and Bloom" A Study in Geological Time and Ephemeral Flora Conceptual Narrative This dish materializes the geological paradox of obsidian—volcanic glass formed in the earth's violent heat, yet appearing as frozen black liquid.
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Our Verdict
GPT-6 Luna
GPT-6 Luna
Kimi K2.5
Kimi K2.5Runner-up

Not enough votes to call it. On the specs, GPT-6 Luna has the edge: newer, bigger context window, major provider backing.

GPT-6 Luna costs 6.0x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

GPT-6 Luna
Input
$0.10
6.0× cheaper
Output
$0.50
6.0× cheaper
Kimi K2.5
Input
$0.60
Output
$3.00

GPT-6 Luna is cheaper on both: 6.0× input, 6.0× output.

Where to run it

8 hosts, cheapest first

GPT-6 Luna3 hosts
HostInOutContextUptime
Azure AI Foundry$0.10 in·$0.50 out·1.1M·88.4% upOpenAI$0.10 in·$0.50 out·1.1M·99.9% upAmazon Bedrock$0.11 in·$0.55 out·1.1M·99.8% up
Kimi K2.55 hosts
HostInOutContextUptime
SSiliconFlowint4$0.45 in·$2.25 out·262k·99.9% upAAtlasCloudint4$0.49 in·$2.50 out·262k·98.7% upVVenice$0.53 in·$3.33 out·256k·98.9% upNNovita$0.57 in·$2.85 out·262k·99% upAmazon Bedrock$0.60 in·$3.00 out·262k·99% up

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

GPT-6 Luna is developed by OpenAI while Kimi K2.5 is developed by Moonshot AI. GPT-6 Luna has a 1.1M token context window vs Kimi K2.5's 262K. You can compare their actual outputs across 20 challenges on Rival to see how they differ in practice.

It depends on your use case. GPT-6 Luna and Kimi K2.5 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 20 challenges so you can judge which fits your needs best.

GPT-6 Luna costs $0.1/M input tokens and Kimi K2.5 costs $0.6/M input tokens. GPT-6 Luna is $0.50/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

This page shows a side-by-side comparison of GPT-6 Luna and Kimi K2.5 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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