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Claude Mythos 5.1 vs Laguna S 2.1

Claude Mythos 5.1 and Laguna S 2.1 are closely matched at 45.3 and 40.6 on the LLM Stats Score. Laguna S 2.1 is 160.0x cheaper per token.

Anthropic · Poolside · Updated for 2026

Which is better?

Claude Mythos 5.1 and Laguna S 2.1 are closely matched on the overall LLM Stats Score at 45.3 and 40.6.

On price, Laguna S 2.1 is roughly 160.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Laguna S 2.1 also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.

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

Choose Claude Mythos 5.1

  • your work emphasizes coding and agents — it leads those capability indexes
  • you want the most recent training data — it shipped Sep 2026

Choose Laguna S 2.1

  • cost matters — it's about 160.0x cheaper per token
  • you process long inputs — it offers a 1,048,576 token context window
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Claude Mythos 5.1
Anthropic
Laguna S 2.1
Poolside
Core performance indexes
LLM Stats Score
45.3
#33
40.6
#57
Reasoning
44.1
#36
40.2
#55
Coding
38.0
#18
30.8
#51
Agents
34.9
#22
24.2
#56
Cost, coverage & limits
Benchmark wins
—
—
Input price
$10.00 / M
$0.10 / M
Output price
$50.00 / M
$0.20 / M
Context window
1,000,000
1,048,576

Individual benchmarks

1 reported for Claude Mythos 5.1 · 6 for Laguna S 2.1

No common benchmarks found

Claude Mythos 5.1 and Laguna S 2.1don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Laguna S 2.1 costs less

For input processing, Claude Mythos 5.1 ($10.00/1M tokens) is 100.0x more expensive than Laguna S 2.1 ($0.10/1M tokens).

For output processing, Claude Mythos 5.1 ($50.00/1M tokens) is 250.0x more expensive than Laguna S 2.1 ($0.20/1M tokens).

In conclusion, Claude Mythos 5.1 is more expensive than Laguna S 2.1.*

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

Lowest available price from all providers
Tue Sep 22 2026 • llm-stats.com
Anthropic
Claude Mythos 5.1
Input tokens$10.00
Output tokens$50.00
Best providerAnthropic
Poolside
Laguna S 2.1
Input tokens$0.10
Output tokens$0.20
Best providerPoolside
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Laguna S 2.1 accepts 1,048,576 input tokens compared to Claude Mythos 5.1's 1,000,000 tokens. Only Claude Mythos 5.1 specifies output context (128,000 tokens).

Anthropic
Claude Mythos 5.1
Input1,000,000 tokens
Output128,000 tokens
Poolside
Laguna S 2.1
Input1,048,576 tokens
Output- tokens
Tue Sep 22 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Mythos 5.1 supports multimodal inputs, whereas Laguna S 2.1 does not.

Claude Mythos 5.1 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Mythos 5.1

Text
Images
Audio
Video

Laguna S 2.1

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Mythos 5.1 is licensed under a proprietary license, while Laguna S 2.1 uses OpenMDW License v1.1.

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

Claude Mythos 5.1

Proprietary

Closed source

Laguna S 2.1

OpenMDW License v1.1

Open weights

Release Timeline

When each model was launched

Claude Mythos 5.1 was released on 2026-09-01, while Laguna S 2.1 was released on 2026-07-21.

Claude Mythos 5.1 is 1 month newer than Laguna S 2.1.

Claude Mythos 5.1

Sep 1, 2026

3 weeks ago

1mo newer
Laguna S 2.1

Jul 21, 2026

2 months 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 5.1 is available from Anthropic. Laguna S 2.1 is available from Poolside.

Claude Mythos 5.1

anthropic logo
Anthropic
Input Price:Input: $10.00/1MOutput Price:Output: $50.00/1M

Laguna S 2.1

poolside logo
Poolside
Input Price:Input: $0.10/1MOutput Price:Output: $0.20/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Mythos 5.1 and Laguna S 2.1 side-by-side, then vote on the output you prefer.

Claude Mythos 5.1
✓ Preferred
Laguna S 2.1
Open in Playground

FAQ

Common questions about Claude Mythos 5.1 vs Laguna S 2.1.

Which is better, Claude Mythos 5.1 or Laguna S 2.1?

Claude Mythos 5.1 and Laguna S 2.1 are closely matched on the LLM Stats Score at 45.3 and 40.6. Claude Mythos 5.1 is made by Anthropic and Laguna S 2.1 is made by Poolside. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Mythos 5.1 compare to Laguna S 2.1 in benchmarks?

Claude Mythos 5.1 scores Terminal-Bench 4.0: 60.9%. Laguna S 2.1 scores SWE-bench Multilingual: 78.5%, Terminal-Bench 2.1: 70.2%, SWE-Bench Pro: 59.4%, Toolathlon: 49.7%, SWE Atlas - Codebase QnA: 46.2%.

Is Claude Mythos 5.1 cheaper than Laguna S 2.1?

Laguna S 2.1 is 100.0x cheaper for input tokens. Claude Mythos 5.1 costs $10.00/M input and $50.00/M output via anthropic. Laguna S 2.1 costs $0.10/M input and $0.20/M output via poolside.

What are the context window sizes for Claude Mythos 5.1 and Laguna S 2.1?

Claude Mythos 5.1 supports 1.0M tokens and Laguna S 2.1 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 5.1 and Laguna S 2.1?

Key differences include LLM Stats Score (45.3 vs 40.6), context window (1.0M vs 1.0M), input pricing ($10.00 vs $0.10/M), multimodal support (yes vs no), licensing (Proprietary vs OpenMDW License v1.1). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Mythos 5.1 and Laguna S 2.1?

Claude Mythos 5.1 is developed by Anthropic and Laguna S 2.1 is developed by Poolside.

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