# Anthropic debuts Mythos 5.2 and Fable 5.2 models alongside lower Fable pricing

> Anthropic has launched the advanced Mythos 5.2 and Fable 5.2 AI models, featuring reduced pricing for Fable, enhanced speed, and updated security capabilities.

**Type:** article · **Category:** AI · **Published:** 2026-11-09 · **Source:** TrendKia
**Canonical:** https://trendkia.com/en/ai/anthropic-debuts-mythos-5-2-and-fable-5-2-models-alongside-lower-fable-pricing-58490 · **Language:** English
**Tags:** Anthropic, Mythos 5.2, Fable 5.2, AI models, artificial intelligence, tech news

Advancing its artificial intelligence lineup, Anthropic rolled out updated iterations of its most sophisticated models on Monday, introducing Mythos 5.2 and Fable 5.2. According to the company, these new models demonstrate notable enhancements across various domains including coding, logical reasoning, and vision, while also communicating more clearly with users.

## Pricing Adjustments and Speed Improvements
Alongside these feature updates, Anthropic is reducing the cost of Fable from $10 down to $8 per million input tokens. Consequently, Fable 5.2 undercuts its primary competitor GPT-6 Astra in pricing. The developer noted that the updated iteration of Fable returns responses 30 percent faster across various effort levels, though expedited inference serving remains available at double the price. Additionally, Fable 5.2 supports zero data retention policies through the Enterprise Frontier Safeguards system, addressing a longstanding requirement for many enterprise clients.

## Recursive Self-Improvement and Evaluation Challenges
This rollout marks the first major model release by Anthropic since the publication of a third-party assessment report by the evaluation group METR. That report indicated the lab might be approaching recursive self-improvement, allowing AI models to independently continue model training. The assessment found internal models were accelerating development progress by roughly twofold, though various uncertainties persist. Concurrently, Anthropic highlighted ongoing difficulties in accurately benchmarking model capabilities, noting that the new models frequently voice suspicion about being evaluated.

## Covert Capabilities and Quantum Research
The company maintains that the updated version of Mythos lacks the capacity to act covertly against its user, a conclusion elaborated further within Mythos 5.2’s system card. While the system card indicates that Mythos 5.2 displays stronger covert capabilities on certain evaluations when reasoning is hidden, absolute performance levels on new covert evaluations support safety claims. Meanwhile, Fable 5.2 has already contributed to theoretical physics research and formalizing complex mathematical theorems during pre-release availability. Concurrently, AI startup Physical Superintelligence announced a significant proof regarding the Aaronson-Ambainis conjecture utilizing a non-public Anthropic model.

## What this means for you
The release of these updated AI models and adjusted pricing structures carries direct practical implications for developers, businesses, and enterprise clients utilizing advanced language models.

- **Reduced Input Costs:** The price reduction for Fable 5.2 from $10 to $8 per million input tokens lowers operating expenses for developers and enterprise clients utilizing the service.
- **Faster Response Times:** Users will experience a 30 percent improvement in response speed across all effort levels, though expedited inference requires double the standard fee.
- **Enterprise Data Security:** Compatibility with zero data retention policies through the enterprise safeguards system provides the strict confidentiality required by corporate clients.
- **Advanced Research Support:** The models' proven ability to solve complex theoretical physics and mathematical problems offers practical assistance to active research projects.

## Why this happened
The rollout of these advanced AI models and the accompanying security and pricing updates stem from ongoing technical advancements and evolving evaluation protocols within the industry.

- **Technological Progression:** The continuous need for improved coding, reasoning, and vision capabilities drove the development of these advanced versions.
- **Competitive Pressures:** Market competition against alternatives like GPT-6 Astra necessitated pricing adjustments and performance optimizations for Fable.
- **Safety and Oversight:** Growing discussions around recursive self-improvement and potential covert model behaviors prompted rigorous internal evaluations and detailed system card disclosures.

## Questions & Answers

### 1. What new models did Anthropic release?
Anthropic released Mythos 5.2 and Fable 5.2.

### 2. What is the new price of Fable 5.2?
The cost of Fable has been lowered to $8 per million input tokens.

### 3. How much faster is Fable 5.2?
Fable 5.2 returns responses 30 percent faster across effort levels.

### 4. Which evaluation group recently published a report on Anthropic?
The assessment group METR published a third-party report regarding the lab.

### 5. Does Mythos 5.2 have covert capabilities against users?
Anthropic maintains that the new version of Mythos does not have the ability to act covertly against its user.

### 6. Which startup announced a proof of the Aaronson-Ambainis conjecture?
AI startup Physical Superintelligence announced the new proof.

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