WORLDTECHAnthropic releases Claude Fable 5.2 and Mythos 5.2 models, both faster than 5.1
Anthropic has launched Claude Fable 5.2 and Claude Mythos 5.2, the second major update to its Fable 5 model class since it arrived in June. The company says both models are faster and more capable than their predecessors, and that the Fable version now costs less.
Two versions with different access
Anthropic describes Fable 5.2 and Mythos 5.2 as its most powerful models so far. Fable 5.2 is open to all eligible users, whereas Mythos 5.2 is reserved for authorized organizations.
According to the reporting, the two models share the same core capabilities. Fable 5.2 blocks certain biology and cybersecurity use cases, while Mythos 5.2 applies looser restrictions.
Gains in coding, reasoning and speed
Anthropic says the models improve coding, reasoning and vision, and that they communicate more clearly with users. Outputs are generated up to 30 percent faster than with the 5.1 versions.
The company claims Fable 5.2 handles challenging software engineering problems and can orchestrate teams of agents on long-running projects. It also reports that the model has solved two open theoretical physics problems.
Anthropic says Claude now writes over 90 percent of the changes merged into its core codebase, with human guidance. In one example, a team of agents running an earlier Fable 5.2 version migrated a critical production service from Python to Rust, and the service now starts about 26 times faster.
Pricing and subscription limits
Fable 5.2 costs $8 per million input tokens and $40 per million output tokens. On demanding tasks set to medium effort, it also uses fewer tokens than Fable 5.1.
Plans that include Fable models receive one to three Fable resets, depending on how long a subscriber has been enrolled. Fable is included for up to 50 percent of weekly usage limits on Pro plans and standard Team seats.
Positioning within Anthropic's model range
Within Anthropic's lineup, Fable is the most capable model, while Haiku, Sonnet and Opus are the smaller and mid-sized options. Anthropic recommends starting with Opus 5.5 for most coding and knowledge tasks, then moving to Fable or Mythos for more complex requests.
Anthropic suggests Fable and Mythos for the most ambitious, open-ended technical work. Benchmarks cited in coverage indicate that the 5.2 models outperform Opus 5.5 in several areas, including computer use, knowledge work, cybersecurity and agentic coding.
Open questions
- How will the authorization process for Mythos 5.2 work for organizations in practice?
- Will the reported benchmark gains hold up under independent evaluation?