Claude Mythos — the Fable 5 codename
Searching for "mythos", "claude mythos", or "mythos 5"? It is a development codename tied to Claude Fable 5. Here is the relationship — and a box to try the model now.
"Mythos" (sometimes "Mythos 5") is a codename that has circulated for Anthropic's latest-generation Claude model, which ships as Claude Fable 5 (model ID claude-fable-5).
If you arrived searching for mythos, the model you are looking for is Fable 5 — and you can try it directly in the box below.
Try the model (Fable 5)
Enter a prompt and run it — the "mythos" model, as Fable 5, answers on this page.
The result will appear here.
Codename vs. product name
AI labs often use internal codenames during development. "Mythos" is the kind of codename that gets attached to a model before its public name is known.
The public-facing name is Claude Fable 5, part of Anthropic's Claude family alongside Opus, Sonnet, and Haiku.
What Fable 5 (mythos) can do
Reasoning
Work through multi-step problems and analysis.
Writing
Draft, rewrite, and summarize with a natural voice.
Coding
Available as claude-fable-5 in Claude Code.
Translation
High-quality translation across many languages.
Frequently asked questions
- Is Mythos the same as Fable 5?
- Mythos is a development codename; the released model is Claude Fable 5 (claude-fable-5).
- What is Mythos 5?
- It refers to the same latest-generation Claude model that ships as Fable 5.
- How do I use it?
- Use it here in the playground, or select claude-fable-5 in Claude Code.