Anthropic releases Fable 5.2 and restricted Mythos 5.2

1. 23:42
   The DecoderFeatured

   Anthropic's Claude Fable 5.2 doesn't generate images, it paints them

   Anthropic's Claude Fable 5.2 creates images by writing Python programs of 1,000 to 2,000 lines that drive a simulated paint engine, placing individual brushstrokes on a virtual canvas rather than using diffusion. Developer Jake Eaton showed a photorealistic parking garage scene made with roughly 700,000 simulated brushstrokes, and engineer Michael Graczyk shared a 21-second video of a bird at sunrise built from exactly 111 strokes, with no undo and deliberate wobble in the lines. Anthropic reports 64.9 percent for Fable 5.2 on its internal RoboDojo Sim benchmark versus 29.8 percent for OpenAI's GPT-6 Astra, though researcher Aris Zhu's real robot-arm comparison found Astra painted faster and was the only model to stand a domino on end.

1. 07:20
   Hacker News AI

   AI #194: Spy versus Guy

   This weekly AI roundup covers the release of Claude Fable 5.2, allegations that Jensen Huang had an affair with a Chinese spy and that Nvidia's board is preparing to remove him, and the METR report on AI R&D acceleration that prompted large timeline updates from Daniel Kokotajlo and Paul Christiano. It also notes that GPT-6 Astra underperforms on safety research tasks, and includes sections on Gemini 4 Carbon, GPT-6 Cyber, benchmarks, AI agents in commerce, and AI safety debates.

1. 22:59
   MarkTechPostFeatured

   Anthropic Launches Claude Fable 5.2 and Mythos 5.2: Same Model, Different Safeguards

   Anthropic released Claude Fable 5.2, a frontier model with a 1M-token context window and 128K max output, available only via hosted API on the Claude Platform, AWS, Google Cloud and Azure at $8/$40 per million input/output tokens. Mythos 5.2 is the same underlying model with fewer cyber and biology safeguards, gated behind Anthropic's Cyber and Life Sciences Verification Programs. Anthropic reports Fable 5.2 ahead of Opus 5.5 on most benchmarks it published, with about 55% fewer blocks than Fable 5.1.

2. 14:34
   Latent SpaceFeatured

   [AINews] Fable 5.2 retakes World #1 LLM spot as $ANT IPO roadshow begins

   Anthropic released Claude Fable 5.2 and Claude Mythos 5.2, which top most independent leaderboards, including Artificial Analysis Intelligence Index v5 at 65, ARC-AGI-3 and SemiAnalysis GDPx at 16.4%, with pricing cut 20% to $8/$40 per million input/output tokens. Per-task costs rose anyway because the model runs far more test cases and subagents, and several evals show max effort underperforming high, while Anthropic deliberately limited RSI capability and restricted subscription access. The launch coincided with the start of Anthropic's $ANT IPO roadshow.

3. 07:58
   Simon Willison

   llm-anthropic 0.31

   Anthropic released Fable 5.2 and Mythos 5.2, and the author added both to llm-anthropic, so prompts can now be run through Fable 5.2 via the llm CLI. Testing pelican SVG generation at all five reasoning levels (low, medium, high, xhigh, max), the best result came from xhigh, while max failed to return an image at all after spending 128,000 tokens thinking. The author notes this is the same bug seen with Opus 5.5 but new for the Fable series, since Fable 5 and Fable 5.1 returned max effort pelicans fine.

4. 05:15
   The DecoderFeatured

   Claude Fable 5.2 and Mythos 5.2 cement Anthropic's AI lead just before its IPO

   Anthropic released Claude Fable 5.2 and Mythos 5.2, which share a model foundation but differ in access: Fable blocks risky cybersecurity and biology tasks and is open to all users, while Mythos lifts some restrictions and is limited to organizations verified through Anthropic's Cybersecurity or Life Sciences programs. Artificial Analysis's Index v5 places Fable 5.2 first at 65 points, five ahead of Gemini 4 Carbon and 15 ahead of Fable 5.1, though per-task costs at the highest tier average $26.50. Anthropic says about 1,000 Fable 5.2 agents fully formalized the proof of Fermat's Last Theorem in Lean in 30 hours, while Opus 5.5 reached only 26 percent in 18 hours in the same setup.

5. 04:04
   AWS Machine Learning BlogFeatured

   Introducing Claude Fable 5.2 on AWS

   Anthropic's Claude Fable 5.2 and Claude Mythos 5.2 are now available on Amazon Bedrock and Claude Platform on AWS, with Fable 5.2 positioned as Anthropic's most capable generally available model for coding, math, and science, and Mythos 5.2 offered through verification programs for cyber security and life sciences work. Fable 5.2 is designated a Covered Model requiring up to 30 days of data retention and human safety review by default, with an aws_review retention mode set on the account or project before invocation, while Enterprise Frontier Safeguards combining zero data retention with misuse detection is in development. The post includes a Boto3 example using model ID global.anthropic.claude-fable-5-2 and describes the claude-api skill in Claude Code for migrating existing codebases.

6. 03:38
   Hacker News AI

   Claude Fable 5.2 now available on AI Gateway

   Anthropic's Claude Fable 5.2 is now available on AI Gateway, with improvements in coding, reasoning, and vision, and the ability to run long, ambiguous tasks unattended or act as an orchestrator or advisor to other Claude models. It has cybersecurity and biology safety classifiers enabled and requires data retention, with prompts and completions retained for 30 days and not used to train Claude; teams with Zero Data Retention enabled receive an error. It is callable via the AI SDK, Chat Completions, Responses, and Anthropic Messages APIs, or a coding agent, using the model name anthropic/claude-fable-5.2, and model fallbacks can keep requests served when a classifier declines them.

7. 03:24
   TechCrunch · AIFeatured

   Anthropic releases new Mythos and Fable models amid RSI concerns

   Anthropic released Mythos 5.2 and Fable 5.2, citing improvements in coding, reasoning, and vision, and lowered Fable's price from $10 to $8 per million input tokens, making it cheaper than GPT-6 Astra, with responses 30% faster across effort levels. It is Anthropic's first release since a METR report suggested the lab might be approaching recursive self-improvement, finding internal models were speeding up Anthropic's AI progress by roughly 2x. Anthropic said the models voice suspicion of being evaluated more often than recent models, and that Mythos 5.2 shows stronger covert capabilities than prior models, though it maintains the model cannot act covertly against its user.

8. 03:22
   Claude Code Releases

   v2.1.321

   Claude Code v2.1.321 adds Claude Fable 5.2 (claude-fable-5-2) as the default Fable model with 1M context and $8/$40 per Mtok pricing, adds a --settings <file> option to claude remote-control, and fixes numerous bugs including MCP OAuth secrets being sent to another host on redirect, sandbox and permission-check issues, and network-path editing problems. It also changes mods to turn on without asking in auto and bypass modes, moves saved Fable 5.1 picks to fable, and adjusts fast mode labels, nested skill loading, and gateway and Windows behaviors.

9. 03:00
   The Verge · AIFeatured

   Anthropic launches new Claude Fable and Mythos 5.2 models

   Anthropic announced Claude Fable 5.2 and Claude Mythos 5.2, which it says improve on coding, reasoning, and vision and generate outputs faster than the 5.1 versions. Anthropic says Fable 5.2 can orchestrate agent teams and handle long-running projects, and that during prerelease testing the models helped engineers with software migrations, designed three working electronic devices, solved two open problems in black hole physics, and formalized the proof of Fermat's Last Theorem in 30 hours. Fable 5.2 launches today, while Mythos 5.2 is initially available only to vetted organizations.

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