Claude’s latest model release date
Anthropic announced Claude Fable 5.2 and Claude Mythos 5.2 on November 9, 2026. The two are versions of the same underlying model, but access differs: Fable includes cybersecurity and biology safeguards and is available for general use; Mythos is restricted to organizations approved through Anthropic’s verification programs. (Anthropic announcement)
For developers, Fable 5.2 is available to all customers on the Claude API. Its API model ID is claude-fable-5-2. Mythos 5.2 is not the general-access API option; organizations must qualify through Anthropic’s verification programs. (Claude Platform documentation)
What the date means
November 9 is the date of Anthropic’s announcement, and the model documentation lists Fable 5.2 as released that day. The API documentation lists it as active and available to Claude API customers. Access on other channels, such as cloud marketplaces, can vary by provider. (Anthropic announcement; Claude Platform documentation)
Which model should you evaluate for production?
- Start with Fable 5.2 if you want to evaluate the generally available model through the Claude API. Anthropic lists a 1-million-token context window and up to 128,000 output tokens. (Claude Platform documentation)
- Consider Mythos 5.2 only if your organization qualifies through Anthropic’s verification programs. (Anthropic announcement)
- Check data-retention requirements: Fable 5.2 requires 30-day data retention and is not available under zero data retention unless Anthropic expressly authorizes it. (Claude Platform documentation)
- Test before switching production traffic. Confirm access in your intended channel and evaluate the model against your workload, latency, quality, and policy requirements. A release date alone does not establish that it is the right fit.
Anthropic lists standard Fable 5.2 API pricing at $8 per million input tokens and $40 per million output tokens. Optional fast mode costs $16 per million input tokens and $80 per million output tokens; Anthropic lists fast-mode availability for the Claude Platform, certain Google Cloud and Microsoft Foundry deployments, and Claude Code. (Claude Fable pricing; Anthropic announcement)
Bottom line: Anthropic announced the Fable 5.2 and Mythos 5.2 models on November 9, 2026. For a generally available production API evaluation, start with Fable 5.2 (claude-fable-5-2); Mythos access is restricted.
Sources
Introducing Claude Fable 5.2 and Claude Mythos 5.2