Anthropic has launched Claude Fable 5.2 and Claude Mythos 5.2, its latest best-in-class AI models. The company says the new models generate outputs up to 30 percent faster than their predecessors and are available at a reduced price of $8 per million input tokens and $40 per million output tokens. Subscribers on eligible paid plans will receive additional Fable usage starting this week.
The Fable 5.2 and Mythos 5.2 models feature improvements in coding, reasoning, and vision, according to Anthropic. The company said testers have found the models communicate more clearly than earlier versions. For coding tasks, Anthropic noted that over 90 percent of changes merged into its core codebase are now written by Claude with human guidance. It cited an example where an earlier version of Fable 5.2 was used to migrate a production service from Python to Rust, resulting in an about 26-times faster start-up and improved efficiency.
Anthropic recommends Fable and Mythos for the most ambitious technical work, while suggesting Claude Opus 5.5 for everyday coding and knowledge tasks. The company also announced that this week, subscribers on paid plans that include Fable will receive one to three usage resets depending on how long they have subscribed. Fable usage is included for up to 50 percent of weekly limits on Pro plans and standard Team seats.
Anthropic first released Fable 5 in June and updated it to Fable 5.1 in September. Fable is the most capable model in its Claude lineup, above Opus, Sonnet, and Haiku.
Claude Fable 5.2 sets a new record on the Epoch Capabilities Index (ECI) at 174. The previous high was GPT-6 Astra’s 169. Fable 5.2’s score is above what the pre-Astra trend for reasoning models would have predicted.
This is notable given recent discussion of AI contributions to AI R&D, and we hope to release more work in this area soon.
This is based on testing we did prior to launch using only our own benchmarks. The ECI is continually updated as more benchmark results become available, and may change in the future.
I had early access to Fable 5.2 for a bit & I think it crosses the line into being a sort of Jagged AGI. Here, I have it launch a business, do academic research, hack hardware, build 3D models & more. I think it is a good illustration of limits & powers: oneusefulthing.org/p/fable-52-and…
The faster and cheaper Fable 5.2 makes advanced AI more accessible for complex software projects.
The demonstrated ability to migrate a production service from Python to Rust suggests AI can play a role in code optimization and modernization.
Extra usage allowances may encourage more developers to experiment with the top-tier models.
Background
Anthropic is an artificial intelligence company behind the Claude family of language models. The Fable class, introduced in mid-2026, is its most capable tier, designed for demanding technical tasks. Smaller models include Opus, Sonnet, and Haiku.
What to Watch
Adoption of Fable 5.2 by enterprises for production coding and cost savings.
Feedback on the claimed 30 percent speed improvement and its impact on developer productivity.
Whether extra usage promotions lead to increased subscriber growth for Anthropic.
12 claims in this story checked against 1 source: 12 supported.
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SupportedAnthropic released Claude Fable 5.2.9to5Mac: “Claude Fable 5.2 arrives today”
SupportedFable 5.2 and Mythos 5.2 generate outputs up to 30 percent faster than their predecessors.9to5Mac: “They generate outputs up to 30% faster than Claude Fable 5.1 and Claude Mythos 5.1”
SupportedThe models cost $8 per million input tokens and $40 per million output tokens.9to5Mac: “they’re available at a lower price: $8 per million input tokens and $40 per million output tokens.”
SupportedAnthropic released Claude Mythos 5.2 as a latest best-in-class model.9to5Mac: “Starting today, Claude Fable 5.2 and Mythos 5.2 are the latest best-in-class models.”
SupportedSubscribers on eligible paid plans get extra Fable usage starting this week.9to5Mac: “This week, we’re giving subscribers on eligible paid plans extra Fable usage.”
SupportedThe new models show improvements in coding, reasoning and vision.9to5Mac: “Claude Fable 5.2 and Claude Mythos 5.2 show improvements in areas like coding, reasoning, and vision.”
SupportedTesters found the models communicate more clearly than earlier versions.9to5Mac: “Testers have found that Fable 5.2 and Mythos 5.2 communicate more clearly than past Fable and Mythos models.”
SupportedMore than 90 percent of changes merged into Anthropic’s core codebase are written by Claude with human guidance.9to5Mac: “Over 90% of the changes merged into Anthropic’s core codebase are now written by Claude (with human guidance).”
SupportedAn earlier version of Fable 5.2 was used to migrate a production service from Python to Rust; the service became more efficient and starts about 26 times faster.9to5Mac: “A team of agents running an earlier version of Fable 5.2 migrated a critical production service from Python to Rust—the service is now more efficient, more reliable, and starts about 26 times faster.”
SupportedAnthropic recommends Fable and Mythos for ambitious technical work and Opus 5.5 for everyday coding and knowledge tasks.9to5Mac: “Fable and Mythos are best for the most ambitious, open-ended technical work. For most coding and knowledge tasks, we recommend that users start with Claude Opus 5.5”
SupportedEligible subscribers get one to three Fable usage resets depending on how long they have subscribed.9to5Mac: “Plans and seats that include Fable models get one to three Fable resets based on how long they’ve subscribed”
SupportedFable is included for up to 50 percent of weekly usage limits on Pro plans and standard Team seats.9to5Mac: “Fable is included for up to 50% of weekly usage limits for Pro plans and standard seats on the Team plan.”
