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Claude Mythos Preview

Deprecated

Invitation-only research preview model for defensive cybersecurity workflows under Project Glasswing (no self-serve sign-up). Will be RETIRED on June 30, 2026; recommended migration to Claude Mythos 5 (claude-mythos-5). Standalone per-model pricing not published on the pricing page (Long context note groups it with the 1M-context models at standard pricing, but no $ figures listed) -> prices null. Included in 1M-token context group. Max output / knowledge cutoff not published (null). As of 2026-06-28 the doc lists it as still functional pending the June 30, 2026 retirement; marked 'deprecated'

Claude Mythos Preview by Anthropic is tracked live in our LLM catalog, with a 1M (1.000.000-token) context window. It is deprecated, shutting down 30 Jun 2026; the recommended replacement is Claude Mythos 5.

Last verified: 13 Aug 2026 · sourced from official provider documentation

Lifecycle warning

This model is deprecated. Scheduled shutdown: 30 Jun 2026. Recommended migration: Claude Mythos 5.

Read the Claude Mythos Preview migration guide → replacement & cheapest alternatives

Provider
Anthropic
Status
Deprecated
Input price
—
Output price
—
Cached input
—
Blended price
—
Context window
1.000.000 tokens (1M)
Max output
—
Modality
text, image, vision
Open weights
No — API only
Knowledge cutoff
—
Released
—
API string
claude-mythos-preview

Source: Anthropic official documentation ↗

See also

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FAQ

Claude Mythos Preview — questions & answers

What is the context window of Claude Mythos Preview?

Claude Mythos Preview has a 1.000.000-token context window (1M).

Is Claude Mythos Preview being deprecated or retired?

Claude Mythos Preview is deprecated. Its scheduled shutdown date is 30 Jun 2026. The recommended migration is Claude Mythos 5.

Does Claude Mythos Preview support image or vision input?

Yes — Claude Mythos Preview accepts image input. Listed modalities: text, image, vision.

Can I self-host Claude Mythos Preview?

No — Claude Mythos Preview is proprietary. Its weights are not publicly released, so it is available only through Anthropic's API (or hosted partners), not for self-hosting.

What is the API model string for Claude Mythos Preview?

The API model identifier for Claude Mythos Preview is "claude-mythos-preview" when calling Anthropic's API.