ModelClaude

Anthropic: Claude Fable 5.2 and Mythos 5.2 are 30% faster

Original title: Introducing Claude Fable 5.2 and Claude Mythos 5.2

Plain language

What it is: Anthropic released Claude Fable 5.2 and Claude Mythos 5.2, which are upgraded models designed for difficult technical tasks. They are up to 30% faster than the previous version, cost less, and have improved coding, reasoning, and vision capabilities.
How it works: Both models share the same underlying technology. Claude Fable 5.2 includes safety guardrails for cybersecurity and biology, while Claude Mythos 5.2 is tailored for approved organizations doing research in those fields.
Where it is available: Claude Fable 5.2 is available to all users. Claude Mythos 5.2 is accessible to organizations that apply through specific verification programs.
Example: A team used the model to migrate a critical software service from Python to Rust, which made the service start 26 times faster.

What it is: Anthropic launched Claude Fable 5.2 and Claude Mythos 5.2, offering improved performance in coding, reasoning, and vision. These models are 30% faster and cheaper than version 5.1, costing $8 per million input tokens and $40 per million output tokens, with an optional fast mode that increases speed by up to 2.5 times.
How it works: The models can be configured with different effort levels, such as Medium, High, or Xhigh effort. Fable 5.2 can also function as an Advisor to other models or as an Orchestrator that delegates tasks to smaller models.
Where it is available: Fable 5.2 is available to all users, while Mythos 5.2 is restricted to organizations in the Life Sciences and Cyber Verification Programs. They are integrated into Claude apps and Claude Code.
Example: An engineer used Fable 5.2 to build a prototype operating system from scratch, which coordinated over 1,000 subagents over eight days to write and test the code.

The headline and explanation on this page are based on Anthropic's post. The full details are in the original.

Introducing Claude Fable 5.2 and Claude Mythos 5.2