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Head-to-head comparison

Muse Spark 1.3 vs GPT-5.5

Muse Spark 1.3 (Meta) and GPT-5.5 (OpenAI) 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 18 October 2026

As of 18 October 2026, Muse Spark 1.3 holds the stronger ModelCap Index position (#6 vs #19); and Muse Spark 1.3 is 7.1× cheaper per output token ($4.25/1M vs $30.00/1M).

Which should you choose?

Choose Muse Spark 1.3 if…

  • you want the stronger overall ModelCap Index position — #6 against #19 (83.4 vs 78.7 points).
  • API cost matters — $4.25/1M output tokens against $30.00/1M, about 7.1× cheaper.
  • your workload is prompt-heavy — input tokens cost $1.25/1M against $5.00/1M.
  • Arena text is your yardstick — 1494 against 1481.
  • Arena coding is your yardstick — 1535 against 1519.
  • LMArena Agent is your yardstick — 3.8% against 3.1%.
  • you want the more recently listed model — Muse Spark 1.3 was listed 2 September 2026, GPT-5.5 24 April 2026.

Choose GPT-5.5 if…

  • you want provider choice — 3 listed API providers against 1.

Muse Spark 1.3 vs GPT-5.5: specs, pricing and context

Specification comparison of Muse Spark 1.3 and GPT-5.5
FieldMuse Spark 1.3MetaGPT-5.5OpenAI
ModelCap Index position#6#19
Index score83.478.7
EvidenceMeasuredMeasured
Input price / 1M tokens$1.25$5.00
Output price / 1M tokens$4.25$30.00
Context window1M tokens1M tokens
Declared route output cap944K128K
API providers listed13
Weight accessNo linked weightsNo linked weights
Input modalitiesText, Image, Video, FileFile, Image, Text
First listed2 September 202624 April 2026
PublisherMetaOpenAI

Evidence: 3 public benchmark observations across 3 boards · 5 public benchmark observations across 5 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Muse Spark 1.3 vs GPT-5.5

Public benchmark boards where Muse Spark 1.3 or GPT-5.5 has a published result
BoardMuse Spark 1.3GPT-5.5Leads
Arena textArena (LMArena)14941489–1500Max14811478–1485HighMuse Spark 1.3
Arena codingArena (LMArena)15351526–1544Max15191513–1524HighMuse Spark 1.3
LMArena AgentLMArena3.8%3.0%–4.7%Max3.1%1.9%–4.4%X-HighMuse Spark 1.3
ARC-AGI-2ARC Prize Foundation—85.0%X-HighOnly one result
ARC-AGI-3ARC Prize Foundation—0.4%HighOnly one result
AA Intelligence IndexArtificial Analysis48.1Max—Only one result
AA Terminal-Bench 2.1Artificial Analysis84.3%Max—Only one result
AA Humanity's Last ExamArtificial Analysis48.7%Max—Only one result
Terminal-Bench 4.0Terminal-Bench (Laude Institute)14.6%11.6%–17.5%Muse Code · X-High—Only one result
Terminal-Bench 2.1 Terminus 2Terminal-Bench—78.0X-HighOnly one result
WildClawBench OpenClawWildClawBench—58.2Only one result

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.

Muse Spark 1.3 vs GPT-5.5: common questions

Is Muse Spark 1.3 better than GPT-5.5?

Muse Spark 1.3 ranks higher on the ModelCap Index as of 18 October 2026: #6 against #19. 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 Muse Spark 1.3 cheaper than GPT-5.5?

Muse Spark 1.3 is cheaper on output tokens: $4.25/1M against $30.00/1M. Input tokens are $1.25/1M for Muse Spark 1.3 and $5.00/1M for GPT-5.5. 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 $4.63 for Muse Spark 1.3 versus $25.00 for GPT-5.5. Muse Spark 1.3 costs 81.5% 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, Muse Spark 1.3 or GPT-5.5?

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, Muse Spark 1.3 or GPT-5.5?

Arena coding: Muse Spark 1.3 1535, GPT-5.5 1519 — Muse Spark 1.3 leads.

Are Muse Spark 1.3 and GPT-5.5 open-weight models?

Muse Spark 1.3: No linked weights. GPT-5.5: 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 Muse Spark 1.3 and GPT-5.5?

ModelCap currently lists 1 API provider for Muse Spark 1.3 and 3 for GPT-5.5, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Muse Spark 1.3 vs GPT-5.5 comparison?

Every figure and ModelCap Index position comes from the same published snapshot dated 18 October 2026. Publication and page updates happen separately; use the snapshot date shown on the page.

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