# Anthropic Claude Mythos Preview — deprecation status

> Yes — Anthropic deprecated Claude Mythos Preview but has not published a shutdown date. It still answers requests today. The recommended replacement is Claude Mythos 5.

The first Mythos-class model, released in April 2026 to a closed group of cyber defenders and critical infrastructure providers under Project Glasswing. It is the only deprecated Claude model with no retirement date on the deprecations page - the notice lives in a callout on the models overview instead, because an invitation-only model has no public user base to give sixty days' notice to.

## Facts

| Field | Value |
| --- | --- |
| Provider | Anthropic |
| Model id | `claude-mythos-preview` |
| Status | Deprecated |
| Last verified | August 3, 2026 |

## Replacement

- **Claude Mythos 5** (`claude-mythos-5`) · recommended — https://modeldeprecations.dev/anthropic/claude-mythos-5
  - Same access model: invitation-only through Project Glasswing, no self-serve sign-up. Mythos 5 is priced at less than half of Mythos Preview.
  - Parameters it accepts: https://modelparams.dev/models/anthropic/claude-mythos-5

```diff
- "model": "claude-mythos-preview"
+ "model": "claude-mythos-5"
```

## FAQ

### When will Anthropic Claude Mythos Preview shut down?

Anthropic has deprecated Anthropic Claude Mythos Preview but has not published a shutdown date. Treat it as at risk and plan a migration.

### What replaces Anthropic Claude Mythos Preview?

Anthropic recommends Claude Mythos 5 (`claude-mythos-5`) as the replacement for Anthropic Claude Mythos Preview. Same access model: invitation-only through Project Glasswing, no self-serve sign-up. Mythos 5 is priced at less than half of Mythos Preview.

### Is Anthropic Claude Mythos Preview still available?

Yes, for now. Anthropic Claude Mythos Preview is deprecated but still answers requests. Deprecated models get no further updates and are the first to lose capacity.

### How do I migrate from Anthropic Claude Mythos Preview to claude-mythos-5?

Swap the model id in your API call: replace "claude-mythos-preview" with "claude-mythos-5". Same access model: invitation-only through Project Glasswing, no self-serve sign-up. Mythos 5 is priced at less than half of Mythos Preview.

## Sources

- [Anthropic model deprecations](https://platform.claude.com/docs/en/about-claude/model-deprecations) — accessed 2026-08-03
- [Anthropic models overview](https://platform.claude.com/docs/en/about-claude/models/overview) — accessed 2026-08-03

---

Canonical page: https://modeldeprecations.dev/anthropic/claude-mythos-preview
JSON: https://modeldeprecations.dev/api/v1/models/anthropic/claude-mythos-preview.json