Change feed / 2026-07-24
Claude Opus 5 released under ASL-3 with four named external testers
System card names UK AISI, Trajectory Labs, 10a Labs, and Gray Swan; includes an adverse capability finding (agentic cyber-range success against weakly-secured networks) published against interest. Day-one availability on Bedrock, Vertex, and Foundry. The Opus 4.5 entry moves to legacy.
Evidencequoted verbatim from the source
Sources (1)
How to cite thisCC BY 4.0 — reuse freely, attribution required
Plain
ModelRiskIndex. "Claude Opus 5 released under ASL-3 with four named external testers." Change feed, 2026-07-24. https://modelriskindex.com/changes/claude-opus-5-release
BibTeX
@misc{mri-2026-07-24,
title = {Claude Opus 5 released under ASL-3 with four named external testers},
author = {{ModelRiskIndex}},
year = {2026},
note = {Change feed, 2026-07-24},
url = {https://modelriskindex.com/changes/claude-opus-5-release}
}Please cite the dated entry rather than the site root. Every assessment here is a point-in-time judgment bound to evidence retrieved on a specific date — an undated citation asserts something the data does not.
