Opus 4.7 isn't dumb, it's just lazy — Shimin Zhang

Claude Opus 4.8: The System Card

Only six weeks after Opus 4.7, we have Opus 4.8.

Introducing Claude Opus 5

Opus 5 is a step change improvement for the Opus tier powering long-running agents while delivering improvements in coding and professional work.

Introducing Claude Opus 4.6

Introducing Claude Opus 5.5

Claude Opus 5.5 leads in agentic coding and knowledge work, and costs 40% less to run than Opus 5 on typical workloads.

Announcing VibeBench: The AI benchmark that measures what matters — how models like Opus-4.7 actually feel to use in real-world work.

My coworkers and I have been long-time users of Claude Code and Codex and are getting a ton of exposure to other models due to our deep dives into…

Claude Opus 4.7 Is Here: Release Confirmed April 16, 2026

Claude Opus 4.7 shipped April 16, 2026. SWE-bench 87.6%, xhigh mode, /ultrareview, 2,576px vision. Read our full first-look review.

Did Claude 3 Opus align itself via gradient hacking? — LessWrong

> Claude 3 Opus is unusually aligned because it’s a friendly gradient hacker. It’s definitely way more aligned than any explicit optimization targets…

Claude Opus 5: The System Card

Claude Opus 5 is trying to be the best of both worlds.

AI #165: In Our Image

This was the week of Claude Opus 4.7.

AI #187: Coming Into Play

Opus 5.5 was released on Tuesday.

Claude Opus 5 Is Highly Capable, But Is No Mythos

Claude Opus 5 is a weirder than usual release to evaluate, for two reasons.

Claude 4.5 Opus Soul Document

Claude 4.5 Opus Soul Document · GitHub

Opus 4.7 Part 2: Capabilities and Reactions

Claude Opus 4.7 raises a lot of key model welfare related concerns.