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Head-to-head comparison

Claude Opus 5.5 vs Muse Spark 1.3

Claude Opus 5.5 (Anthropic) and Muse Spark 1.3 (Meta) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 7 November 2026

As of 7 November 2026, Claude Opus 5.5 holds the stronger ModelCap Index position (#2 vs #5); and Muse Spark 1.3 is 4.7× cheaper per output token ($4.25/1M vs $20.00/1M).

Which should you choose?

Choose Claude Opus 5.5 if…

  • you want the stronger overall ModelCap Index position — #2 against #5 (86.8 vs 83.9 points).
  • you want provider choice — 5 listed API providers against 1.
  • Arena text is your yardstick — 1505 against 1495.
  • Arena coding is your yardstick — 1549 against 1533.
  • LMArena Agent is your yardstick — 20.1% against 2.5%.
  • Terminal-Bench 4.0 is your yardstick — 64.9% against 14.6%.
  • you want the more recently listed model — Claude Opus 5.5 was listed 22 September 2026, Muse Spark 1.3 2 September 2026.

Choose Muse Spark 1.3 if…

  • API cost matters — $4.25/1M output tokens against $20.00/1M, about 4.7× cheaper.
  • your workload is prompt-heavy — input tokens cost $1.25/1M against $4.00/1M.

Claude Opus 5.5 vs Muse Spark 1.3: specs, pricing and context

Specification comparison of Claude Opus 5.5 and Muse Spark 1.3
FieldClaude Opus 5.5AnthropicMuse Spark 1.3Meta
ModelCap Index position#2#5
Index score86.883.9
EvidenceMeasuredMeasured
Input price / 1M tokens$4.00$1.25
Output price / 1M tokens$20.00$4.25
Context window1M tokens1M tokens
Declared route output cap128K944K
API providers listed51
Weight accessNo linked weightsNo linked weights
Input modalitiesText, Image, FileText, Image, Video, File
First listed22 September 20262 September 2026
PublisherAnthropicMeta

Evidence: 4 public benchmark observations across 4 boards · 3 public benchmark observations across 3 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Claude Opus 5.5 vs Muse Spark 1.3

Public benchmark boards where Claude Opus 5.5 or Muse Spark 1.3 has a published result
BoardClaude Opus 5.5Muse Spark 1.3Leads
Arena textArena (LMArena)15051499–1511High14951490–1501MaxClaude Opus 5.5
Arena codingArena (LMArena)15491538–1560High15331525–1541MaxClaude Opus 5.5
LMArena AgentLMArena20.1%18.1%–22.2%Max2.5%1.7%–3.3%MaxClaude Opus 5.5
ARC-AGI-2ARC Prize Foundation93.3%High—Only one result
AA Intelligence IndexArtificial Analysis59.1Max—Only one result
Terminal-Bench 4.0Terminal-Bench (Laude Institute)64.9%61.7%–68.0%Claude Code · Max14.6%11.6%–17.5%Muse Code · X-HighClaude Opus 5.5

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Claude Opus 5.5 vs Muse Spark 1.3: common questions

Is Claude Opus 5.5 better than Muse Spark 1.3?

Claude Opus 5.5 ranks higher on the ModelCap Index as of 7 November 2026: #2 against #5. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.

Is Claude Opus 5.5 cheaper than Muse Spark 1.3?

Muse Spark 1.3 is cheaper on output tokens: $4.25/1M against $20.00/1M. Input tokens are $4.00/1M for Claude Opus 5.5 and $1.25/1M for Muse Spark 1.3. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $18.00 for Claude Opus 5.5 versus $4.63 for Muse Spark 1.3. Muse Spark 1.3 costs 74.3% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.

Which has the bigger context window, Claude Opus 5.5 or Muse Spark 1.3?

Both publish a 1M-token context window. OpenRouter catalogue or provider-endpoint declaration. Limits can vary by provider and prompt length; a model-wide maximum has not been independently verified.

Which is better for coding, Claude Opus 5.5 or Muse Spark 1.3?

Arena coding: Claude Opus 5.5 1549, Muse Spark 1.3 1533 — Claude Opus 5.5 leads. Terminal-Bench 4.0: Claude Opus 5.5 64.9%, Muse Spark 1.3 14.6% — Claude Opus 5.5 leads.

Are Claude Opus 5.5 and Muse Spark 1.3 open-weight models?

Claude Opus 5.5: No linked weights. Muse Spark 1.3: No linked weights. Open weights mean the checkpoint can be downloaded and self-hosted under its licence. A missing weight link does not identify every API or chat product that offers a model.

Where can I run Claude Opus 5.5 and Muse Spark 1.3?

ModelCap currently lists 5 API providers for Claude Opus 5.5 and 1 for Muse Spark 1.3, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Claude Opus 5.5 vs Muse Spark 1.3 comparison?

Every figure and ModelCap Index position comes from the same published snapshot dated 7 November 2026. Publication and page updates happen separately; use the snapshot date shown on the page.

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