Claude Mythos Preview

GPAI Provider: Anthropic

Metadata

Model URL: https://www.anthropic.com/claude/mythos
When was this model published? 2026-06-02
Is this a new or a fine-tuned model? New model
When was the Public Summary last updated? 2026-07-24
When did we evaluate the Public Summary? 2026-08-04
Where did we find the Public Summary? We found this document linked on this page. An archived version can be found here.

Results of Evaluation

Section Transparency Usefulness General
Clarity Completeness Consistency Correctness Accessibility Comprehension Transparency Usefulness
Document 81.82 100.0 100.0 60.0 85.0 66.67 85.19 76.32
General information 48.48 73.61 100.0 93.33 50.0 90.91 71.09 78.12
Public Data Sources 34.78 18.42 100.0 100.0 0.0 100.0 36.13 44.44
Private Data Sources 0.0 27.27 100.0 100.0 N/A 100.0 34.69 100.0
Scraped/Crawled Data 100.0 39.87 100.0 59.14 0.0 34.48 65.27 24.1
User Data 0.0 42.31 100.0 100.0 100.0 0.0 45.45 50.0
Synthetic/Other Data 26.15 30.85 100.0 100.0 100.0 0.0 51.21 41.46
Data Processing 100.0 58.33 100.0 100.0 100.0 47.83 90.0 57.14
Sum 55.95 39.67 100.0 83.67 54.21 46.33 56.45 48.92
Grades CD+

Evaluation Notes

If you update your public summary, please let us know so that we can update the evaluation and scores. We also welcome suggestions on improvements to this page, e.g. see FAQ section.

Anthropic provides training data summaries which, on the whole, describe training data only on a high level. Relevant characteristics of training data are described either at a high level or not at all. No individual datasets are described besides the CommonCrawl. Descriptions of crawlers meet requisite standards, however the content they crawled is not described in sufficient detail. Services used to collect user data, and models used to generate synthetic data, are not enumerated. Lastly, the data summary contains little detail on how the provider ensures that they are up-to-date with user right requests. The summary scores 56.45% with Grade C for transparency and 48.92% with Grade D+ for usefulness.

Suggested Improvements
The following are the suggested improvements based on using our our methodology where the public summary had issues related to the specified metric. The severity represents the extent of the issue, with low indicating aspects that could be fixable, and high representing missing information or requiring major changes.

  • Document
    • M1 The document and the information should be simple and clear low
    • M4 The information must be correct and accurate medium
    • M5 The document and information must be accessible for stakeholders low
    • M6 The document and information must be comprehensible for stakeholders medium
  • General information
    • M1 The document and the information should be simple and clear high
    • M2 The document and information must be filled in completely medium
    • M4 The information must be correct and accurate low
    • M5 The document and information must be accessible for stakeholders medium
    • M6 The document and information must be comprehensible for stakeholders low
  • Public Data Sources
    • M1 The document and the information should be simple and clear high
    • M2 The document and information must be filled in completely high
    • M5 The document and information must be accessible for stakeholders high
  • Private Data Sources
    • M1 The document and the information should be simple and clear high
    • M2 The document and information must be filled in completely high
  • Scraped/Crawled Data
    • M2 The document and information must be filled in completely high
    • M4 The information must be correct and accurate medium
    • M5 The document and information must be accessible for stakeholders high
    • M6 The document and information must be comprehensible for stakeholders high
  • User Data
    • M1 The document and the information should be simple and clear high
    • M2 The document and information must be filled in completely high
    • M6 The document and information must be comprehensible for stakeholders high
  • Synthetic/Other Data
    • M1 The document and the information should be simple and clear high
    • M2 The document and information must be filled in completely high
    • M6 The document and information must be comprehensible for stakeholders high
  • Data Processing
    • M2 The document and information must be filled in completely medium
    • M6 The document and information must be comprehensible for stakeholders high
  • Sum
    • M1 The document and the information should be simple and clear medium
    • M2 The document and information must be filled in completely high
    • M4 The information must be correct and accurate low
    • M5 The document and information must be accessible for stakeholders medium
    • M6 The document and information must be comprehensible for stakeholders high