Development

One model sweeps the board and jumps the capability curve

development2026-04-08

Claim

Claude Mythos posted 93.9% on SWE-bench Verified, 94.6% on GPQA Diamond, 56.8% on Humanity's Last Exam without tools and 82.0% on Terminal Bench 2.0, marking an apparent upward discontinuity on the Epoch Capabilities Index after a two-year trend, though it costs five times Opus.

Reported metric: 93.9% SWE-bench / 56.8% HLE

Reporting date: 2026-04-08 (not necessarily the event date)

Sources

Attribution and reporting linked by this record; links do not imply independent verification.

Welcome to April 8, 2026 (theinnermostloop.substack.com)

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About

Claude Mythos

Reported in

Welcome to April 8, 2026

Actor

Anthropic

Evidence for

Supersedes

A new benchmark returns frontier models to near zero

Referenced by

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Citation formatCitation text

One model sweeps the board and jumps the capability curve
Innermost Loop KB — secondary record
Reporting date: 2026-04-08
KB permalink: https://nicholsn.github.io/innermost-loop-kb/developments/2026-04-08-mythos-benchmark-sweep
Claim: Claude Mythos posted 93.9% on SWE-bench Verified, 94.6% on GPQA Diamond, 56.8% on Humanity's Last Exam without tools and 82.0% on Terminal Bench 2.0, marking an apparent upward discontinuity on the Epoch Capabilities Index after a two-year trend, though it costs five times Opus.
Attributed sources:
- Welcome to April 8, 2026 — https://theinnermostloop.substack.com/p/welcome-to-april-8-2026
This citation does not imply independent verification of linked-source claims.

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