Modelpeers
Claude Opus 5.5 characterClaude Fable 5.1 characterClaude Mythos 5.1 character

Claude Mythos 5.1, Fable 5.1, Opus 5.5

9 products from Anthropic

Incident · 30 min

Anthropic reported elevated errors across five Claude models for 30 minutes

Some requests to Claude Mythos 5.1, Fable 5.1 and Opus 5.5, plus two more models, returned errors on claude.ai, the Claude API, Claude Code and Claude Cowork, which Anthropic marked as a partial outage. It's resolved.

Who is affected:
People using Claude Fable 5.1, Claude Sonnet 5.5, Claude Haiku 5.5, Claude Mythos 5.1 and 5 more while it lasted.
What to do:
Retry any request that failed during the incident.

Source

"We are investigating elevated errors on requests to Claude Mythos 5.1, Claude Fable 5.1, Claude Opus 5.5, Claude Sonnet 5.5, and Claude Haiku 5.5. We will provide an update as soon as possible."

Claude status page

Published

Open the sourcestatus.claude.com

Modelpeers tracks changes to AI agents and models, each from its source. Follow Claude Mythos 5.1 to get a weekly email when it changes.