AISystem

Claude Opus 5.5

Sources

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

Welcome to September 24, 2026 (theinnermostloop.substack.com)
Source linked by the September 24 issue (www.anthropic.com)
Welcome to September 29, 2026 (theinnermostloop.substack.com)

Anthropic model released with reported improvements in cost, capability and alignment auditing.

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Development timeline

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

2026-10-13: Muse Wonder Full scores 56 on the Artificial Analysis index

2026-10-12: Opus 5.5 reportedly enables hundreds of game recreations

2026-10-12: Opus 5.5 is plotted at an eleven-hour-plus task horizon

2026-10-10: A developer reportedly builds seven open-source Adobe alternatives

2026-10-10: Insiders claim Google is approaching recursive self-improvement

2026-10-09: Musk says Grok will route some work to Opus 5.5

2026-10-03: Breen’s agents uncover an overlooked historical log

2026-10-03: Opus 5.5 reportedly leads Epoch’s index

2026-09-29: A user reports Opus building a computer from logic gates

2026-09-29: A commentator compares Opus with a researcher-replacement threshold

2026-09-29: Sonnet 5.5 scores 56 on the Artificial Analysis index

2026-09-29: Sonnet 5.5 improves on Terminal-Bench 4.0

2026-09-24: A post claims OpenAI was surprised by the Opus release

2026-09-24: Users demonstrate code-based visual art with Opus

2026-09-24: Users praise Opus 5.5's visual design

2026-09-24: Opus 5.5 leads the Artificial Analysis index

2026-09-24: Anthropic releases Claude Opus 5.5

2026-09-24: Opus agents reportedly devise a faster asymptotic shortest-path algorithm

2026-09-24: A user reports rapid low-cost video production with Opus

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Developed by

Anthropic

Evaluated on

Referenced by

Grok

Cite or correct this record

Citation formatCitation text

Claude Opus 5.5
Innermost Loop KB — secondary record
Reporting date: unknown
KB permalink: https://nicholsn.github.io/innermost-loop-kb/systems/claude-opus-5-5
Attributed sources:
- Welcome to September 24, 2026 — https://theinnermostloop.substack.com/p/welcome-to-september-24-2026
- Source linked by the September 24 issue — https://www.anthropic.com/claude-opus-5-5
- Welcome to September 29, 2026 — https://theinnermostloop.substack.com/p/welcome-to-september-29-2026
This citation does not imply independent verification of linked-source claims.

Suggest a correction — opens a GitHub draft for you to review and submit.