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  5. Claude Opus 4.5vsSeed 2.1 Turbo
Updated Aug 2026

Claude Opus 4.5vsSeed 2.1 Turbo

Seed 2.1 Turbo is the newer model, released after Claude Opus 4.5.

Claude Opus 4.5 and Seed 2.1 Turbo compared across 53 shared prompts
SpecClaude Opus 4.5Seed 2.1 Turbo
Input price—$0.5/M tokens
Output price—$2.5/M tokens
Context window—262K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedNov 2025Aug 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 53 prompts both answered. Formatting stripped, words untouched.

Character Voice Test

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

Claude Opus 4.5181 words
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?
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Seed 2.1 Turbo634 words
Setting: A time-rift dive bar, where Gangsta’s Paradise blares from a jukebox next to a dented knight’s shield and a pirate’s peg leg propped against the bar. Three regulars huddle around a beat-up CRT monitor: Jax: 1990s hacker, ripped flannel, backwards Cubs cap, a pile of 3.5” floppies spilling out of his backpack…
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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…

Claude Opus 4.5207 words
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…
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Seed 2.1 Turbo1,433 words
1-Month Beginner Longevity Plan Who This Is For People with zero consistent health routine, busy schedules, no gym access, and no desire for restrictive diets or extreme changes. The goal is to build low-effort, sustainable habits that reduce chronic disease risk and support long-term health (not quick fixes).
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Futuristic Prediction

Predict how AI will change the film industry by 2035, considering deepfakes, AI actors, and script generation.

Claude Opus 4.5194 words
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…
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Seed 2.1 Turbo1,482 words
By 2035, AI will not replace human creativity in film, but it will restructure nearly every layer of the industry—from pre-production to distribution—with deepfakes, AI actors, and script generation serving as core tools shaped by a decade of labor negotiations, regulatory guardrails, and audience feedback.
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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…

Claude Opus 4.5154 words
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.
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Seed 2.1 Turbo432 words
Dish Name: Pantry Lava Chickpea Crisp A cozy, savory one-skillet meal with bubbly garlicky tomato sauce studded with crispy chickpeas, topped with a crunchy spiced oat crumble. Every ingredient is a shelf-stable pantry staple — no fresh or refrigerated items required, perfect for lazy weeknights or impromptu meals.
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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…

Claude Opus 4.51,169 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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Seed 2.1 Turbo1,851 words
This analysis is general in nature and not a substitute for legal advice from a licensed attorney in your jurisdiction, as contract law varies significantly by location and context. Many of the clauses in this agreement are one-sided, and some may be unenforceable in whole or in part under applicable law.
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Generate a Stand-Up Routine

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

Claude Opus 4.5288 words
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.
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Seed 2.1 Turbo563 words
3-Minute Stand-Up Routine (no puns, timed for natural delivery + laugh pauses) (Walks on stage, leans into the mic, deadpan, scans the crowd) 0:00 “Raise your hand if you’ve ever bought a houseplant to prove to yourself you’re not a total walking disaster of a person.
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Our Verdict
Claude Opus 4.5
Claude Opus 4.5
Seed 2.1 Turbo
Seed 2.1 TurboRunner-up

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

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Opus 4.5
Input
—
Output
—
Seed 2.1 Turbo
Input
$0.50
Output
$2.50
Where to run it

5 hosts

Claude Opus 4.54 hosts
HostInOutContextUptime
Amazon Bedrock$5.00 in·$25.00 out·200k·100% upAzure AI Foundry$5.00 in·$25.00 out·200k·100% upAnthropic$5.00 in·$25.00 out·200k·99.9% upGoogle Vertex AI$5.00 in·$25.00 out·200k·100% up
Seed 2.1 Turbo1 host
HostInOutContextUptime
ByteDance Seedfp8$0.50 in·$2.50 out·262k·100% up

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

Writing DNA

Style Comparison

Similarity
34%

Claude Opus 4.5 uses 3.9x more bold

Claude Opus 4.5
Seed 2.1 Turbo
66%Vocabulary50%
51wSentence Length27w
0.82Hedging0.27
6.0Bold1.5
4.5Lists2.4
0.18Emoji0.07
1.46Headings1.01
0.05Transitions0.04
Based on 27 + 27 text responses
Research

What we learned reading every model

FAQ

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Model pages

Claude Opus 4.5 logo
Claude Opus 4.558 outputs, specs and price
Seed 2.1 Turbo logo
Seed 2.1 Turbo58 outputs, specs and price
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