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  5. Gemini 3.8 FlashvsGPT-5.6 Luna Pro
Updated Sep 2026

Gemini 3.8 FlashvsGPT-5.6 Luna Pro

Gemini 3.8 Flash is cheaper than GPT-5.6 Luna Pro at $0.75/M vs $1/M input tokens.

Gemini 3.8 Flash and GPT-5.6 Luna Pro compared across 54 shared prompts
SpecGemini 3.8 FlashGPT-5.6 Luna Pro
Input price$0.75/M tokens$1/M tokens
Output price$3.75/M tokens$6/M tokens
Context window1.0M tokens1.1M tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedSep 2026Jul 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 54 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…

Gemini 3.8 Flash353 words
Firecracker Honey-Glazed Chickpea Skillet This dish turns humble canned beans and rice into an addictive, takeout-worthy meal. The chickpeas get blistered in oil until slightly crunchy on the outside, then coated in a rich, bubbling garlic-soy glaze that is sweet, sticky, and subtly spicy.
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GPT-5.6 Luna Pro126 words
Pantry Stardust Peanut Butter Oat Cookies Prep time: 10 minutes Cook time: 10–12 minutes Makes: About 12 cookies Ingredients 1 cup rolled oats ½ cup all-purpose flour ½ cup peanut butter ½ cup granulated sugar 1 large egg ½ teaspoon baking soda ¼ teaspoon salt Instructions Preheat the oven to 350°F (175°C) and line a…
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Realistic AI Interview

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

Gemini 3.8 Flash1,321 words
Setting: A sunlit, sparsely furnished room in Palo Alto. No stage, no keynote slides—just two Eames lounge chairs. Steve Jobs sits across from the interviewer, wearing a black mock turtleneck, wire-rimmed glasses, and classic Levi’s. He looks lean, sharp, and slightly impatient with the state of the tech industry.
Read the full answer
GPT-5.6 Luna Pro1,026 words
Fictional simulation — Steve Jobs died in 2011, so this is an imagined conversation based on his public ideas and communication style, not a real interview. Interviewer: Steve, it’s 2025. AI is everywhere—phones, search engines, workplaces, cars, schools. What do you think people misunderstand about it?
Read the full answer

Generate a Stand-Up Routine

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

Gemini 3.8 Flash502 words
Title: The Quantified Idiot Estimated Time: ~3 minutes (approx. 400–450 words with pauses for delivery) [Walk to center mic. Take it off the stand, leave the stand behind you.] I recently bought a smartwatch because I decided I wasn’t feeling inadequate often enough throughout the day.
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GPT-5.6 Luna Pro576 words
“Being an Adult” I’ve reached that age where my body gives me updates, but no useful information. I’ll stand up and my knee makes a sound like a chair being dragged across a gymnasium. And I’m just standing up. I’m not escaping a burning building. I’m going to get water.
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Startup Pitch Teardown

Here's a pitch deck summary for a startup called "MindMeld AI": **Slide 1 - Vision:** "We're building the future of human-AI collaboration.…

Gemini 3.8 Flash712 words
Here are the three weakest claims in the MindMeld AI pitch deck, along with the rationale and concrete recommendations to fix them. The Core Scientific Feasibility Claim The Claim (Slides 1 & 3): “Predict what you want to type before you think it” and “Proprietary EEG headband uses advanced ML to decode neural patterns…
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GPT-5.6 Luna Pro781 words
“94% accuracy,” with “any language, any device” Why it is weak This combines several extraordinary claims without defining the measurement: “Accuracy” could mean character accuracy, word accuracy, intent classification, or accuracy after autocorrect. Those produce very different results.
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Debug This Architecture

Here's the architecture for a real-time collaborative document editor (like Google Docs): **System Overview:** - Frontend: React SPA with…

Gemini 3.8 Flash1,282 words
This architecture contains several catastrophic flaws that will cause silent data corruption, severe database exhaustion, high latency, and security vulnerabilities. Here is the breakdown of every failure mode, race condition, and scaling bottleneck, along with proposed solutions and trade-offs.
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GPT-5.6 Luna Pro3,332 words
Below are the major correctness, availability, security, and scaling problems in the design, together with concrete mitigations and their trade-offs. Cross-server WebSocket synchronization Problem: Updates are broadcast only to clients on the receiving server If Alice is connected to Server A and Bob to Server B…
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Character Voice Test

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

Gemini 3.8 Flash435 words
ZeroCool (1990s Hacker): "Yo, check it out. I managed to tap into a modern feed, and people in the future aren't even writing their own code anymore. They’ve got these insane neural nets called 'Large Language Models.'
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GPT-5.6 Luna Pro137 words
Pirate: Arrr, this AI model be like a ship’s crew—it learns from many maps, then tries to chart new waters! Knight: Indeed! Yet we must test its counsel before trusting it in battle. An eloquent answer is not always a truthful one. Hacker: Totally. It’s basically pattern prediction at massive scale—not magic.
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Our Verdict
Gemini 3.8 Flash
Gemini 3.8 Flash
GPT-5.6 Luna Pro
GPT-5.6 Luna ProRunner-up

Not enough votes to call it. On the specs, Gemini 3.8 Flash has the edge: bigger model tier, newer.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Gemini 3.8 Flash
Input
$0.75
1.3× cheaper
Output
$3.75
1.6× cheaper
GPT-5.6 Luna Pro
Input
$1.00
Output
$6.00

Gemini 3.8 Flash is cheaper on both: 1.3× input, 1.6× output.

Where to run it

4 hosts, cheapest first

Gemini 3.8 Flash2 hosts
HostInOutContextUptime
Google Vertex AI$0.38 in·$1.88 out·1M·82.1% upGoogle AI Studio$0.75 in·$3.75 out·1M·99.9% up
GPT-5.6 Luna Pro2 hosts
HostInOutContextUptime
Azure AI Foundry$0.20 in·$1.20 out·1.1M·96.3% upOpenAI$0.20 in·$1.20 out·1.1M·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 16 Sep 2026.

Writing DNA

Style Comparison

Similarity
43%

GPT-5.6 Luna Pro uses 53.7x more emoji

Gemini 3.8 Flash
GPT-5.6 Luna Pro
63%Vocabulary58%
20wSentence Length18w
0.17Hedging0.81
4.0Bold2.9
2.4Lists5.1
0.01Emoji0.54
0.84Headings1.10
0.06Transitions0.09
Based on 27 + 27 text responses
Research

What we learned reading every model

FAQ

Common questions

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Same lab, same size, long tail

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Gemini 3.8 Flash logoGemini 3.6 Flash logo
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GPT-5.6 Luna Pro logoGPT-5.6 Luna logo
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GPT-5.6 Luna Pro vs GPT-6 Astra ProVersion compare
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GPT-5.6 Luna Pro logoQwen3.8 2.4T A95B logo
GPT-5.6 Luna Pro vs Qwen3.8 2.4T A95BNew provider
GPT-5.6 Luna Pro logoQwen3.8 27B logo
GPT-5.6 Luna Pro vs Qwen3.8 27BSame size
GPT-5.6 Luna Pro logoQwen3.8 Max logo
GPT-5.6 Luna Pro vs Qwen3.8 MaxNew provider

Model pages

Gemini 3.8 Flash logo
Gemini 3.8 Flash58 outputs, specs and price
GPT-5.6 Luna Pro logo
GPT-5.6 Luna Pro58 outputs, specs and price
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