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introducing-claude-fable-5-and-claude-mythos-5 changedmodels/fable-5/introducing-claude-fable-5-and-claude-mythos-5

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1212 Access to Claude Fable 5 and Claude Mythos 5 has been restored. See [our statement](https://www.anthropic.com/news/redeploying-fable-5) for more information.
1313</Tip>
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15Claude Fable 5 is built for demanding reasoning and long-horizon agentic work. Claude Mythos 5 shares the same capabilities and is available only in limited release through [Project Glasswing](https://anthropic.com/glasswing).
15Claude Fable 5 is built for demanding reasoning and long-horizon agentic work. Claude Mythos 5 shares the same capabilities and is available only to organizations verified through Anthropic's verification programs, such as the [Cyber Verification Program](https://support.claude.com/en/articles/14604842).
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1717The headline change for integrations: Claude Fable 5 includes safety classifiers that can decline requests. If your integration calls Claude Fable 5, plan for three changes: new response handling for refusals, fallback options for retrying on another Claude model, and new billing rules. [Refusals, fallback, and billing on Claude Fable 5](https://platform.claude.com/docs/en/models/fable-5/introducing-claude-fable-5-and-claude-mythos-5#refusals-fallback-and-billing-on-claude-fable-5) summarizes all three.
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1919## Models
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21| Model | API model ID | Description |
22| --------------- | ----------------- | -------------------------------------------------------------------------------------------------------------- |
23| Claude Fable 5 | `claude-fable-5` | Built for demanding reasoning and long-horizon agentic work |
24| Claude Mythos 5 | `claude-mythos-5` | Shares Claude Fable 5's capabilities. Available through Project Glasswing. Successor to Claude Mythos Preview. |
21| Model | API model ID | Description |
22| --------------- | ----------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
23| Claude Fable 5 | `claude-fable-5` | Built for demanding reasoning and long-horizon agentic work |
24| Claude Mythos 5 | `claude-mythos-5` | Shares Claude Fable 5's capabilities. Available only to organizations verified through Anthropic's verification programs, such as the [Cyber Verification Program](https://support.claude.com/en/articles/14604842). Successor to Claude Mythos Preview. |
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2626Claude Fable 5 and Claude Mythos 5 share the same specs and pricing:
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5353## Availability
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5555* **Claude Fable 5** is available on the Claude API, [Amazon Bedrock](https://platform.claude.com/docs/en/build-with-claude/claude-in-amazon-bedrock), [Claude Platform on AWS](https://platform.claude.com/docs/en/build-with-claude/claude-platform-on-aws), [Google Cloud](https://platform.claude.com/docs/en/build-with-claude/claude-on-vertex-ai), and [Microsoft Foundry](https://platform.claude.com/docs/en/build-with-claude/claude-in-microsoft-foundry).
56* **Claude Mythos 5** is offered only to approved customers in [Project Glasswing](https://anthropic.com/glasswing). For access, contact your Anthropic, AWS, or Google Cloud account team. Customers without access to Claude Mythos 5 can use Claude Fable 5, which does not require access approval and offers the same capabilities.
56* **Claude Mythos 5** is available only to organizations verified through Anthropic's verification programs, such as the [Cyber Verification Program](https://support.claude.com/en/articles/14604842). Customers without access to Claude Mythos 5 can use Claude Fable 5, which does not require access approval and offers the same capabilities.
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5858Claude Fable 5 and Claude Mythos 5 carry 30-day data retention and are not available under zero data retention unless expressly authorized by Anthropic. Both are designated [Covered Models](https://support.claude.com/en/articles/15425695). See [Model-specific data retention requirements](https://platform.claude.com/docs/en/manage-claude/api-and-data-retention#model-specific-data-retention-requirements).
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