# Anthropic releases Claude Fable 5.2 and Mythos 5.2 with lower prices and faster mode

> The new models add a 1‑million token window, cost $8 / M input tokens, and offer an optional fast mode that speeds output up to 2.5×.

Oossa · 2026-11-09 · https://oossa.com/en/anthropic-releases-claude-fable-5-2-and-mythos-5-2-with-lower-prices-and-faster-

Event date: 2026-11-09

Anthropic announced on November 9, 2026 that it is now offering Claude Fable 5.2 and Claude Mythos 5.2. Both models support a 1 million‑token context window and can generate up to 128 k tokens in one response. The main change for users is price: input tokens cost $8 USD per million and output tokens $40 USD per million, down from $10 / $50 for the previous 5.1 versions. The models also introduce an optional “fast mode” that can produce up to 2.5 times more output tokens per second for $16 / $80 per million input and output tokens respectively. They are available through the Claude API, on Anthropic’s Claude Platform on AWS, and as Claude Models on Google Cloud (both Anthropic‑ and Google‑managed).

## What’s new under the hood?

Fable 5.2 is the open‑access version, while Mythos 5.2 is limited to organizations that pass Anthropic’s Cyber or Life‑Sciences verification programs. Both models enforce the prefix check on every account, preventing system‑prompt edits that would otherwise cause a 400 error. They also support the newer computer_toolset_20260801; older toolsets now return errors. A new “advisor” tool in beta lets an executor model use only Fable 5.2 or Mythos 5.2 as its advisor, ensuring compatibility. Data retention defaults to 30 days, and the models cannot be run under a zero‑retention policy without special permission.

## Why it matters

Anthropic says the upgrades improve coding, reasoning, and vision tasks. In internal tests the models solved complex engineering problems, helped design three electronic devices from scratch, and even formalized a proof of Fermat’s Last Theorem in 30 hours. Benchmarks show Fable 5.2 scoring higher than Claude Opus 5.5 on most of the evaluated tasks, and Mythos 5.2 catching 10 % more vulnerabilities than Opus 5.5 in a cybersecurity benchmark. The lower price and fast mode make large‑scale, long‑horizon projects—like multi‑step code generation or scientific simulations—more affordable for companies that can meet the verification requirements.

## The facts

- Claude Fable 5.2 and Claude Mythos 5.2 were launched on November 9, 2026 ("November 9, 2026").
- Both models have a 1 million token context window and a 128 k token maximum output.
- Input costs $8 USD per million tokens and output $40 USD per million tokens, versus $10 / $50 for the 5.1 versions.
- Fast mode can deliver up to 2.5 × higher output token rate for $16 / $80 per million input and output tokens.
- Mythos 5.2 is restricted to organizations verified through Anthropic’s Cyber or Life‑Sciences programs.

## Why it matters

For developers and research teams, the cheaper pricing and larger context window mean they can run more ambitious AI‑assisted projects without breaking the bank. Companies in regulated fields can still use the high‑capability Mythos model if they pass Anthropic’s verification, opening up AI help for cybersecurity and biotech work that previously required multiple smaller models.

## Sources & references

1. [docs.anthropic.com: November 9, 2026](https://docs.anthropic.com/en/release-notes/api#november-9-2026) – Anthropic API, 2026-11-09
2. [New on OpenRouter: Anthropic: Claude Fable 5.2](https://openrouter.ai/anthropic/claude-fable-5.2) – OpenRouter API, 2026-11-07
3. [Anthropic releases new Mythos and Fable models amid RSI concerns](https://techcrunch.com/2026/11/09/anthropic-releases-new-mythos-and-fable-models-amid-rsi-concerns/) – TechCrunch, 2026-11-09
4. [Introducing Claude Fable 5.2 and Claude Mythos 5.2](https://www.anthropic.com/claude-fable-and-mythos-5-2) – Anthropic
5. [Anthropic releases first frontier models since Amodei's call for slowdown as IPO buzz builds](https://www.cnbc.com/2026/11/09/anthropic-claude-fable-5-2-mythos-5-2.html) – CNBC, 2026-11-09
6. [Anthropic launches new Claude Fable and Mythos 5.2 models](https://www.theverge.com/ai-artificial-intelligence/1030005/anthropic-claude-fable-mythos-5-2) – The Verge, 2026-11-09

Last updated: 2026-11-09