Claude Opus 5.5vsMuse Spark

Claude Opus 5.5
Muse Spark
Specifications
Context window
1M
API pricing
Input price
$4.00
Output price
$20.00
Cached input price
$0.20
Benchmarks
Humanity's Last Exam · with tools
67.7%50.4%
Benchmarks
Gray Swan IPI · k = 1
2.9%
Gray Swan IPI · k = 10
14.3%
Gray Swan IPI · k = 15
16.5%
SWE-Bench Pro
55%
SWE-Bench Verified
77.4%
DeepSWE 1.1
10%
FrontierCode v1.1 (Main) · main split
54.4%
Terminal-Bench 4.0
66.4%
Terminal-Bench 2.1
67.3%
Terminal-Bench-Science 0.1
58.7%
MCP Atlas
82.2%
JobBench
17%
Toolathlon-Verified
49.4%
ARC-AGI-2
42.5%
GPQA Diamond
89.5%
OSWorld 2.0
81.8%
OSWorld-Verified
53.3%
AutomationBench
40%
GDPval-AA v2.1
1846
CharXiv Reasoning
88.9%
Chartography · with tools
89%
BabyVision
39.9%
MMMU
80.4%
Overview
CompanyAnthropicMeta
Release dateSep 22 2026Apr 8 2026
AccessProprietaryProprietary

Other comparisons

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Frequently asked questions

Claude Opus 5.5 leads Muse Spark on 1 of the 1 benchmark they both report (Humanity's Last Exam). Only Claude Opus 5.5 has a verified first-party API price: $4.00 per million input tokens and $20.00 per million output tokens. No pay-as-you-go API rate is tracked for Muse Spark. Muse Spark shipped 167 days before Claude Opus 5.5, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

On Humanity's Last Exam · with tools, Claude Opus 5.5 leads at 67.7% vs Muse Spark at 50.4%.