Claude Mythos 5
Jul 2026 · Restricted · Restricted · supported evidence
Anthropic’s limited-access peak. Tops composite boards, but you cannot buy it on the public API. Treat Fable 5 as the available twin.
Intelligence
63.4
AA Index
API price
$10 / $50
Input / output per 1M
Context
1M
Speed unlisted
Capability
Intelligence Index63.4
Coding index78
Agentic index58
Arena Elo (offset)—
Use it when
- ▸Eval research
- ▸Internal Anthropic-class workloads
Skip if
- –You need a generally available API
Benchmarks
GPQA Diamond Graduate-level science questions designed so Google search is not enough. Still one of the cleanest knowledge/reasoning splits. | 94.1% |
|---|---|
Humanity’s Last Exam Expert-written questions across fields. Harder than MMLU; the current differentiator for “does this model actually know things.” | 64.7% |
MMLU-Pro Harder, less-saturated successor to MMLU. Classic MMLU is above 90% for every flagship and no longer ranks the field. | — |
SWE-bench Verified 500 human-validated GitHub issues. Score swings 5–15 points by harness — treat vendor numbers as an upper bound. | 93.9% |
SWE-bench Pro Harder, contamination-resistant coding eval. Currently the best public split between “can code” and “can maintain a repo.” | 80.3% |
Terminal-Bench 2.1 End-to-end tasks in a real terminal. Better proxy for coding agents than HumanEval, which is fully saturated. | — |
ARC-AGI-2 Abstract visual puzzles. Rewards generalization over memorization. GPT-5.6 Sol currently leads the published set. | — |
AIME 2025 American Invitational Mathematics Examination. Contest math; reasoning-mode models dominate. | — |
MMMU College-level multimodal understanding across diagrams, charts, and exam figures. | — |
Restricted access as of August 2026.
Modalities
text · vision · tools
Reasoning mode
hybrid
Hybrid and reasoning models spend tokens thinking. That raises GPQA and agents, and also raises latency and bill.