Anthropic has made its most powerful artificial intelligence model available to the public for the first time, releasing Claude Fable 5, a consumer-facing version of its previously restricted Mythos model, just days after a temporary infrastructure failure disrupted AI services for tens of thousands of users on productivity platform Notion.
The dual developments in a single week have put Anthropic’s reliability and capability under simultaneous scrutiny. The service disruption, which affected Anthropic’s Opus 4.7 and 4.8 models over the weekend, led Notion to temporarily disable all Anthropic models in its automated productivity tools. Notion head of product Max Schoening later clarified that the outage was a routine infrastructure issue unrelated to model quality, and that access had been fully restored. An Anthropic spokesperson confirmed the incident, describing it as a brief infrastructure issue that elevated error rates across multiple Claude models before being resolved.
Against that backdrop, Anthropic moved forward with the commercial rollout of Fable 5, positioning it as a step-change in AI performance for software engineering, knowledge work, and vision tasks. The model is available through the Claude API and consumption-based Enterprise plans, priced at $10 per million input tokens and $50 per million output tokens, double the cost of Opus 4.8.
Early independent testing has been striking. Ethan Mollick, an AI researcher at the University of Pennsylvania, reported that Fable outperformed every other public model he had tested by a considerable margin, noting it could execute complex multi-page specifications over extended sessions and generate fully playable video games from a single prompt using Claude Code. Analytics firm Hex reported Fable was the first model to score 90 percent on its core benchmark for complex analytical tasks.
Anthropic says at least 95 percent of Fable sessions run entirely on the model’s own responses, with fallback to Opus 4.8 reserved for high-risk queries in areas such as cybersecurity and biology.
