The Model Index
Models/Anthropic

Claude Mythos Preview

AnthropicReleased 7 Apr 2026ClosedFlagshipDate verified
–Index scoreNot yet evaluated independently
1/ 8Core tests taken1 of 6 areas · plus 0 anchor tests
–Versus the frontier at releaseReplaced by Claude Mythos 5
–Price per million tokensno public API price found
–Context windowtokens it reads at once

Where it sitson the frontier

Among the first models to reach this score.

Test resultsby area · tick = best by any model

Reasoning & knowledgeno evidence yet
GPQA Diamond
no result
Humanity's Last Exam
no result
Mathsno evidence yet
FrontierMath T1-3
no result
Codingno evidence yet
SWE-bench Verified
no result
Terminal-Bench
no result
Agentsno evidence yet
APEX-Agents
no result
Novel problemsno evidence yet
ARC-AGI-2
no result
Long tasksevidence
METR time horizon
17 h

Independent results from the Epoch AI benchmarking hub, best reasoning setting. The core tests are shown here; anchor tests also inform the score and can be shown above.

What others sayrank on each leaderboard

Not on any of the rankings we follow yet.

Further left is better. Leaderboards measure different things: LMArena is people voting blind between two answers, the others are test scores. Click any row for the source.

Best attop three among current models

Where this model places in the top three of today's models, on category leaderboards and on our core tests.

Where to use itprices checked 1 Oct 2026

Provider prices come from OpenRouter's live listing; going direct to a provider can differ. Subscriptions are the lab's own apps.

Facts and sources

Released7 Apr 2026
Announcementanthropic.com ↗
Release entryClaude Mythos Preview (restricted; Project Glasswing)
Scored asClaude Mythos Preview
Artificial Analysis index–
Output speed–
Hugging Faceclosed weights

Anthropic releasesaround this one