Claude Opus 5.1 release date: there is no Claude Opus 5.1

Claude Opus 5.1 doesn't exist. There is no Opus 5.1. Opus 5 shipped in July and the 5.1 generation went out as Fable and Mythos, so this entry exists to catch the name if it ever turns up.

Status

Doesn't exist

People usually mean

Claude Opus 5 or Claude Fable 5.1

Explained: Claude models explained: Opus 5.5, Fable 5.1, Mythos and why there's no Opus 5.1

Posts that mention Claude Opus 5.1

There is no Claude Opus 5.1, so nothing here was made with it. These are 3 posts that use the name. If a post shows work, it was most likely made with Claude Opus 5 or Claude Fable 5.1.

Each card is the original post, shown the way X or Reddit embeds it, with a link to where it came from. We picked the ones that show something being made and skipped the benchmark screenshots. We can't vouch for any of them being unedited.

What we've written about Claude Opus 5.1

What is Claude Opus 5.1?

Claude Opus 5.1 is a name that turns up in posts and searches, not a model Anthropic has released or announced.

Is Claude Opus 5.1 coming?

Nothing says it is. Anthropic hasn't announced a model by that name, and we won't invent a date for one. If you came here for the model people usually mean, that's Claude Opus 5 or Claude Fable 5.1.

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More news: Anthropic news and Claude updates

Updated 2026-10-29 23:32 UTC.