All tasks / Comparisons

Claude Opus 5.5 vs Muse Spark 1.3

Compared only on public benchmark results, across the 6 tasks where both are listed: Claude Opus 5.5 is a tier higher in 2 of 6 shared tasks, Muse Spark 1.3 in 1, they share a tier in 3.

Claude Opus 5.5

Anthropic's Opus-tier Claude model for long-running agentic coding and knowledge work.

Vendor: Anthropic
Weights: Closed: API and apps only
Released: 22 Sep 2026
API price: $4 in / $20 out per 1M tokens
License: proprietary
Last verified: 18 Oct 2026

Alternatives to Claude Opus 5.5

Muse Spark 1.3

Meta's mid-tier proprietary Muse model line, offered through Meta's API.

Vendor: Meta
Weights: Closed: API and apps only
Released: Sep 2026
API price: $1.25 in / $4.25 out per 1M tokens
License: proprietary
Last verified: 18 Oct 2026

Alternatives to Muse Spark 1.3

Task by task

Task	Claude Opus 5.5	Muse Spark 1.3	Higher tier
Chat & assistants Models	S1,508 on LMArena Text Arena (overall, style control) · Cloud	S1,494 on LMArena Text Arena (overall, style control) · Cloud	Same tier
Writing Models	S1,519 on LMArena Text Arena: Creative Writing (style control) · Cloud	A1,461 on LMArena Text Arena: Creative Writing (style control) · Cloud	Claude Opus 5.5
Coding Models	S1,806 on LMArena WebDev / Code Arena (overall) · Cloud	B1,659 on LMArena WebDev / Code Arena (overall) · Cloud	Claude Opus 5.5
Image understanding Models	S1,293 on LMArena Vision Arena (overall, style control) · Cloud	S1,290 on LMArena Vision Arena (overall, style control) · Cloud	Same tier
Vector graphics & logos Models	C1,332 on Design Arena SVG · Cloud	C1,323 on Design Arena SVG · Cloud	Same tier
Browser & computer agents Models	–No public result yet · Cloud	A39.3% on OSWorld 2.0 (end-to-end models) · Cloud	Muse Spark 1.3

A tier spans a range of scores, and small gaps on a leaderboard are often within its margin of error, so only a different tier counts as ahead. How we rank.

Same benchmark, both results

Benchmark	Claude Opus 5.5	Muse Spark 1.3	Snapshot
Artificial Analysis Intelligence Index Composite index over Artificial Analysis' own evaluation suite, higher is better	58 Claude Opus 5.5 (Max, Default Fallback)	48 Muse Spark 1.3 (Max)	18 Oct 2026
Artificial Analysis MMMU-Pro (independent evaluation) Accuracy on MMMU-Pro (multi-discipline multimodal questions over images), as run by Artificial Analysis, higher is better	87.7% Claude Opus 5.5 (Max, Default Fallback)	82% Muse Spark 1.3 (Xhigh)	19 Oct 2026
Design Arena SVG Elo rating from crowdsourced blind pairwise votes on SVG markup that models generate from a prompt (icons, illustrations, diagrams, artistic compositions), higher is better	1,332 Claude Opus 5.5	1,323 Muse Spark 1.3 Max	19 Oct 2026
EQ-Bench Creative Writing v3 Elo score from LLM-judged pairwise comparisons of creative-writing outputs (rubric score shown alongside), higher is better	2,050 claude-opus-5-5	1,906 muse-spark-1.3	24 Sep 2026
LMArena Text Arena (overall, style control) Arena score (Bradley-Terry rating from pairwise human votes, style-controlled default view), higher is better	1,508 Claude Opus 5.5 (High)	1,494 Muse Spark 1.3 (Max)	15 Oct 2026
LMArena Text Arena: Creative Writing (style control) Arena score (Bradley-Terry rating from pairwise human votes, creative-writing prompts only, style-controlled view), higher is better	1,519 Claude Opus 5.5 (High)	1,461 Muse Spark 1.3 (Max)	15 Oct 2026
LMArena Vision Arena (overall, style control) Arena score (Bradley-Terry rating from pairwise human votes on image + text prompts, style-controlled view), higher is better	1,293 claude-opus-5.5-high	1,290 muse-spark-1.3-max	9 Oct 2026
LMArena WebDev / Code Arena (overall) Arena score (Bradley-Terry rating from pairwise human votes on web-app generation), higher is better	1,806 Claude Opus 5.5 (Max)	1,659 Muse Spark 1.3 (Max)	18 Oct 2026