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Claude Mythos 5

Anthropic · 2026-06-09

Claude Mythos 5 is a Mythos-class model and the successor to Claude Mythos Preview, offered in limited availability to approved customers through Project Glasswing. It shares Claude Fable 5's underlying model and capabilities but does not include Fable 5's safety classifiers.

Benchmark scores

BenchmarkScore
BioMysteryBench - Human Difficult46.5
BioMysteryBench - Human Solvable89.0
BrowseComp93.3
Capability164.2
Chartography85.2
CyberGym83.8
DeepSearchQA (F1 score)94.2
ExploitBench Leaderboard (Capability coverage)78.0
ExploitBench Leaderboard (Mean capability score, out of 16)10.8
Firefox 147 Exploit Development88.4
Firefox 147 Exploit Development (Any Progress)90.0
GDP.pdf (Mean Criteria Pass Rate)87.3
GPQA Diamond94.1
GraphWalks BFS - 1M79.4
GraphWalks BFS - 256K91.1
HealthBench62.5
HealthBench Professional70.3
HealthBench Professional (Length-Adjusted)66.0
Humanity's Last Exam64.5
OfficeQA79.0
OfficeQA Pro67.1
OSS-Fuzz (Anthropic)80.0
OSWorld-Verified85.0
ProgramBench93.0
RiemannBench55.0
scBench59.3
SpatialBench Verified69.2
SWE-bench Multilingual92.2
SWE-bench Multimodal54.9
SWE-Bench Pro (Public Dataset)80.3
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