The AI arena is free today

Open Superagent

Claude Mythos Preview vs Muse Spark Open

Claude Mythos Preview leads the LLM Stats Score 54.5 to 45.3. Muse Spark Open is 25.0x cheaper per token.

Anthropic · Meta · Updated for 2026

Which is better?

Claude Mythos Preview leads the overall LLM Stats Score 54.5 to 45.3, ranking #5 overall.

The models split the 2 individual benchmarks reported for both models evenly.

On price, Muse Spark Open is roughly 25.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Claude Mythos Preview

  • overall performance matters — it scores 54.5 and ranks #5 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes

Choose Muse Spark Open

  • cost matters — it's about 25.0x cheaper per token
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Claude Mythos Preview
Anthropic
Muse Spark Open
Meta
Core performance indexes
LLM Stats Score
54.5
#5
45.3
#42
Reasoning
55.6
#4
45.7
#35
Coding
43.8
#4
33.5
#40
Agents
36.6
#19
30.8
#43
Cost, coverage & limits
Benchmark wins
1 of 2
1 of 2
Input price
$25.00 / M
$1.25 / M
Output price
$125.00 / M
$4.25 / M
Context window
—
1,048,576

Capability indexes

Additional strengths measured across groups of related public benchmarks

3 shared
Index
Claude Mythos Preview
Muse Spark Open
Math
47.4#1
33.3#58
Vision
39.7#5
31.3#33
Multimodal
37.0#8
33.1#20
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

16 reported for Claude Mythos Preview · 17 for Muse Spark Open

2 shared

Claude Mythos Preview outperforms in 1 benchmarks (GPQA), while Muse Spark Open is better at 1 benchmark (OSWorld-Verified).

Both models are evenly matched across the benchmarks.

Fri Oct 23 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Muse Spark Open costs less

For input processing, Claude Mythos Preview ($25.00/1M tokens) is 20.0x more expensive than Muse Spark Open ($1.25/1M tokens).

For output processing, Claude Mythos Preview ($125.00/1M tokens) is 29.4x more expensive than Muse Spark Open ($4.25/1M tokens).

In conclusion, Claude Mythos Preview is more expensive than Muse Spark Open.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Fri Oct 23 2026 • llm-stats.com
Anthropic
Claude Mythos Preview
Input tokens$25.00
Output tokens$125.00
Best providerAnthropic
Meta
Muse Spark Open
Input tokens$1.25
Output tokens$4.25
Best providerTogether
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Only Muse Spark Open specifies input context (1,048,576 tokens). Only Muse Spark Open specifies output context (1,048,576 tokens).

Anthropic
Claude Mythos Preview
Input- tokens
Output- tokens
Meta
Muse Spark Open
Input1,048,576 tokens
Output1,048,576 tokens
Fri Oct 23 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Mythos Preview and Muse Spark Open support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Claude Mythos Preview

Text
Images
Audio
Video

Muse Spark Open

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Mythos Preview is licensed under a proprietary license, while Muse Spark Open uses Muse Model License.

License differences may affect how you can use these models in commercial or open-source projects.

Claude Mythos Preview

Proprietary

Closed source

Muse Spark Open

Muse Model License

Open weights

Release Timeline

When each model was launched

Muse Spark Open was released on 2026-10-15, while Claude Mythos Preview's release date is not specified.

We can confirm Muse Spark Open's release timeline, but cannot make a direct age comparison without Claude Mythos Preview's release date.

Claude Mythos Preview

—

Muse Spark Open

Oct 15, 2026

4 days ago

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

Claude Mythos Preview is available from Anthropic. Muse Spark Open is available from Together.

Claude Mythos Preview

anthropic logo
Anthropic
Input Price:Input: $25.00/1MOutput Price:Output: $125.00/1M

Muse Spark Open

together logo
Together
Input Price:Input: $1.25/1MOutput Price:Output: $4.25/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Claude Mythos Preview and Muse Spark Open side-by-side, then vote on the output you prefer.

Claude Mythos Preview
✓ Preferred
Muse Spark Open
Open in Playground

FAQ

Common questions about Claude Mythos Preview vs Muse Spark Open.

Which is better, Claude Mythos Preview or Muse Spark Open?

Claude Mythos Preview leads the LLM Stats Score 54.5 to 45.3. Claude Mythos Preview is made by Anthropic and Muse Spark Open is made by Meta. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Mythos Preview compare to Muse Spark Open in benchmarks?

Claude Mythos Preview scores CyBench: 100.0%, USAMO25: 97.6%, GPQA: 94.6%, SWE-Bench Verified: 93.9%, CharXiv-R: 93.2%. Muse Spark Open scores MCP Atlas: 89.2%, GPQA: 89.0%, OSWorld-Verified: 80.4%, BabyVision: 80.2%, Terminal-Bench 2.1: 76.4%.

Is Claude Mythos Preview cheaper than Muse Spark Open?

Muse Spark Open is 20.0x cheaper for input tokens. Claude Mythos Preview costs $25.00/M input and $125.00/M output via anthropic. Muse Spark Open costs $1.25/M input and $4.25/M output via together.

What are the context window sizes for Claude Mythos Preview and Muse Spark Open?

Claude Mythos Preview supports an unknown number of tokens and Muse Spark Open supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Mythos Preview and Muse Spark Open?

Key differences include LLM Stats Score (54.5 vs 45.3), input pricing ($25.00 vs $1.25/M), licensing (Proprietary vs Muse Model License). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Mythos Preview and Muse Spark Open?

Claude Mythos Preview is developed by Anthropic and Muse Spark Open is developed by Meta.

Related comparisons