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Head-to-head comparison

Claude Fable 5.1 vs Muse Spark 1.3

Claude Fable 5.1 (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 18 October 2026

As of 18 October 2026, Claude Fable 5.1 holds the stronger ModelCap Index position (#3 vs #6); and Muse Spark 1.3 is 11.8× cheaper per output token ($4.25/1M vs $50.00/1M).

Which should you choose?

Choose Claude Fable 5.1 if…

  • you want the stronger overall ModelCap Index position — #3 against #6 (85.8 vs 83.4 points).
  • you want provider choice — 4 listed API providers against 1.
  • Arena text is your yardstick — 1502 against 1494.
  • Arena coding is your yardstick — 1537 against 1535.
  • LMArena Agent is your yardstick — 14.0% against 3.8%.
  • AA Intelligence Index is your yardstick — 53.4 against 48.1.
  • AA Terminal-Bench 2.1 is your yardstick — 91.4% against 84.3%.
  • AA Humanity's Last Exam is your yardstick — 59.1% against 48.7%.
  • Terminal-Bench 4.0 is your yardstick — 57.9% against 14.6%.

Choose Muse Spark 1.3 if…

  • API cost matters — $4.25/1M output tokens against $50.00/1M, about 11.8× cheaper.
  • your workload is prompt-heavy — input tokens cost $1.25/1M against $10.00/1M.
  • you want the more recently listed model — Muse Spark 1.3 was listed 2 September 2026, Claude Fable 5.1 1 September 2026.

Claude Fable 5.1 vs Muse Spark 1.3: specs, pricing and context

Specification comparison of Claude Fable 5.1 and Muse Spark 1.3
FieldClaude Fable 5.1AnthropicMuse Spark 1.3Meta
ModelCap Index position#3#6
Index score85.883.4
EvidenceMeasuredMeasured
Input price / 1M tokens$10.00$1.25
Output price / 1M tokens$50.00$4.25
Context window1M tokens1M tokens
Declared route output cap128K944K
API providers listed41
Weight accessNo linked weightsNo linked weights
Input modalitiesText, Image, FileText, Image, Video, File
First listed1 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 Fable 5.1 vs Muse Spark 1.3

Public benchmark boards where Claude Fable 5.1 or Muse Spark 1.3 has a published result
BoardClaude Fable 5.1Muse Spark 1.3Leads
Arena textArena (LMArena)15021496–1508Max14941489–1500MaxClaude Fable 5.1
Arena codingArena (LMArena)15371526–1549Max15351526–1544MaxClaude Fable 5.1
LMArena AgentLMArena14.0%12.0%–16.0%Max3.8%3.0%–4.7%MaxClaude Fable 5.1
ARC-AGI-2ARC Prize Foundation90.0%Max—Only one result
AA Intelligence IndexArtificial Analysis53.4Reasoning48.1MaxClaude Fable 5.1
AA Terminal-Bench 2.1Artificial Analysis91.4%Reasoning84.3%MaxClaude Fable 5.1
AA Humanity's Last ExamArtificial Analysis59.1%Reasoning48.7%MaxClaude Fable 5.1
Terminal-Bench 4.0Terminal-Bench (Laude Institute)57.9%54.1%–61.6%Claude Code · Max14.6%11.6%–17.5%Muse Code · X-HighClaude Fable 5.1

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 Fable 5.1 vs Muse Spark 1.3: common questions

Is Claude Fable 5.1 better than Muse Spark 1.3?

Claude Fable 5.1 ranks higher on the ModelCap Index as of 18 October 2026: #3 against #6. 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 Fable 5.1 cheaper than Muse Spark 1.3?

Muse Spark 1.3 is cheaper on output tokens: $4.25/1M against $50.00/1M. Input tokens are $10.00/1M for Claude Fable 5.1 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 $45.00 for Claude Fable 5.1 versus $4.63 for Muse Spark 1.3. Muse Spark 1.3 costs 89.7% 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 Fable 5.1 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 Fable 5.1 or Muse Spark 1.3?

Arena coding: Claude Fable 5.1 1537, Muse Spark 1.3 1535 — Claude Fable 5.1 leads. AA Terminal-Bench 2.1: Claude Fable 5.1 91.4%, Muse Spark 1.3 84.3% — Claude Fable 5.1 leads. Terminal-Bench 4.0: Claude Fable 5.1 57.9%, Muse Spark 1.3 14.6% — Claude Fable 5.1 leads.

Are Claude Fable 5.1 and Muse Spark 1.3 open-weight models?

Claude Fable 5.1: 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 Fable 5.1 and Muse Spark 1.3?

ModelCap currently lists 4 API providers for Claude Fable 5.1 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 Fable 5.1 vs Muse Spark 1.3 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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