Published paper and code explanation, not our model or hardware replication
How quantum programs meet external checks and proofs →
The eight tasks do not share a zero-error criterion.
Anthropic · Released 2026-06-09
Claude Mythos 5
The restricted model used in the quantum-circuit study. Results come from a model, coding environment and author-built evaluator loop, not Opus 5.5 or measured quantum-hardware acceleration. Current family access guidance covers the later 5.1, not general access to this older version.
Original model explanation ↗No comparable leaderboard score is included yet. Explore the evaluations and examples below.
Evaluations: conditions and results
Official research account, not our model or hardware test
Eight circuit tasks, programmatic evaluation and validation scope ↗
Author paper, not independent replication
Original paper: circuit resources, correctness and implementations ↗
Current family guidance, not proof of public access to the old model
Verified access to the later 5.1 and version distinctions ↗
Anthropic model evolution
- Claude Mythos 5 · 受限发布
Shares an underlying model with Fable 5, with different safeguards and access; the initial release is for selected partner organizations, not general availability.
Original release ↗ - Claude Mythos 5 → 5.1
The later 5.1 continues verified access; the October quantum-circuit research explicitly uses Mythos 5, not 5.1, Fable or Opus.
Original release ↗ - Opus 5 → Opus 5.5
An update to complex work and communication, with public code-animation and same-prompt game examples.
Original release ↗ - Sonnet 5 → Sonnet 5.5
The second 5.5-family model emphasizes everyday work, speed and effort-dependent costs.
Original release ↗ - Haiku 4.5 → Haiku 5.5
The lightweight model gains adjustable effort and lower short-prompt rates for extraction, classification and subagent work.
Original release ↗