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Claude Mythos 5.1 vs GPT-6 Rosalind

Comparing Claude Mythos 5.1 and GPT-6 Rosalind across benchmarks, pricing, and capabilities.

Anthropic · OpenAI · Updated for 2026

Which is better?

Claude Mythos 5.1 and GPT-6 Rosalind trade strengths across price, capabilities, and technical limits. The better choice depends on the workload.

On price, Claude Mythos 5.1 is roughly 1.5x 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 5.1

  • cost matters — it's about 1.5x cheaper per token

Choose GPT-6 Rosalind

  • you want the most recent training data — it shipped Oct 2026

At a glance

The differences that matter most.

Claude Mythos 5.1
Anthropic
GPT-6 Rosalind
OpenAI
Benchmark wins
—
—
Input price
$10.00 / M
$15.00 / M
Output price
$50.00 / M
$75.00 / M
Context window
1,000,000
—

Individual benchmarks

1 reported for Claude Mythos 5.1 · 0 for GPT-6 Rosalind

No common benchmarks found

Claude Mythos 5.1 and GPT-6 Rosalinddon'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

Claude Mythos 5.1 costs less

For input processing, Claude Mythos 5.1 ($10.00/1M tokens) is 1.5x cheaper than GPT-6 Rosalind ($15.00/1M tokens).

For output processing, Claude Mythos 5.1 ($50.00/1M tokens) is 1.5x cheaper than GPT-6 Rosalind ($75.00/1M tokens).

In conclusion, GPT-6 Rosalind is more expensive than Claude Mythos 5.1.*

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

Lowest available price from all providers
Sun Nov 08 2026 • llm-stats.com
Anthropic
Claude Mythos 5.1
Input tokens$10.00
Output tokens$50.00
Best providerAnthropic
OpenAI
GPT-6 Rosalind
Input tokens$15.00
Output tokens$75.00
Best providerOpenAI
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Only Claude Mythos 5.1 specifies input context (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
OpenAI
GPT-6 Rosalind
Input- tokens
Output- tokens
Sun Nov 08 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Mythos 5.1 and GPT-6 Rosalind support multimodal inputs.

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

Claude Mythos 5.1

Text
Images
Audio
Video

GPT-6 Rosalind

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Claude Mythos 5.1

Proprietary

Closed source

GPT-6 Rosalind

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Mythos 5.1 was released on 2026-09-01, while GPT-6 Rosalind was released on 2026-10-30.

GPT-6 Rosalind is 2 months newer than Claude Mythos 5.1.

Claude Mythos 5.1

Sep 1, 2026

2 months ago

GPT-6 Rosalind

Oct 30, 2026

1 weeks ago

1mo newer

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. GPT-6 Rosalind is available from OpenAI.

Claude Mythos 5.1

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

GPT-6 Rosalind

openai logo
OpenAI
Input Price:Input: $15.00/1MOutput Price:Output: $75.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Claude Mythos 5.1 and GPT-6 Rosalind side-by-side, then vote on the output you prefer.

Claude Mythos 5.1
✓ Preferred
GPT-6 Rosalind
Open in Playground

FAQ

Common questions about Claude Mythos 5.1 vs GPT-6 Rosalind.

Which is better, Claude Mythos 5.1 or GPT-6 Rosalind?

Claude Mythos 5.1 (Anthropic) and GPT-6 Rosalind (OpenAI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does Claude Mythos 5.1 compare to GPT-6 Rosalind in benchmarks?

Claude Mythos 5.1 scores Terminal-Bench 4.0: 60.9%.

Is Claude Mythos 5.1 cheaper than GPT-6 Rosalind?

Claude Mythos 5.1 is 1.5x cheaper for input tokens. Claude Mythos 5.1 costs $10.00/M input and $50.00/M output via anthropic. GPT-6 Rosalind costs $15.00/M input and $75.00/M output via openai.

What are the context window sizes for Claude Mythos 5.1 and GPT-6 Rosalind?

Claude Mythos 5.1 supports 1.0M tokens and GPT-6 Rosalind supports an unknown number of 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 GPT-6 Rosalind?

Key differences include input pricing ($10.00 vs $15.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Mythos 5.1 and GPT-6 Rosalind?

Claude Mythos 5.1 is developed by Anthropic and GPT-6 Rosalind is developed by OpenAI.

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