AISystem

Claude Opus 4

An earlier generation of Anthropic's Opus line, cited in the corpus as the baseline that managed 3x on the lab's standing training-code speedup test.

reasoning-model

Sources

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

Welcome to June 5, 2026 (theinnermostloop.substack.com)

Claude Opus 4 preceded Claude Opus 4.5 and Claude Opus 4.6 in Anthropic’s flagship line (announcement). It appears in this corpus as the reference point in the When AI builds itself report: where Opus 4 managed 3x on the standing training-code speedup test, Mythos Preview reached ~52x, the comparison the newsletter uses to show how quickly the loop’s inner task is being automated.

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Development timeline

Newest reporting dates first. Reporting dates may differ from event dates.

2026-06-05: A model speeds up training code thirteen times better than a skilled human

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Same as

http://www.wikidata.org/entity/Q134885159

Developed by

Anthropic

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Claude Opus 4
Innermost Loop KB — secondary record
Reporting date: unknown
KB permalink: https://nicholsn.github.io/innermost-loop-kb/systems/claude-opus-4
Attributed sources:
- Welcome to June 5, 2026 — https://theinnermostloop.substack.com/p/welcome-to-june-5-2026
This citation does not imply independent verification of linked-source claims.

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