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ZDNET's key takeaways
Fable 5 accelerates AI's success rate on remote tasks to 16%.
AI capabilities remain all over the map.
Still, agent skills have "quadrupled in under eight months," said CAIS.
After a brief hiatus, Anthropic's lauded Fable 5 model is back, and it's resetting the bar for automating work.
The US government re-authorized the model -- which Anthropic said shares capability similarities with Mythos 5, still only available for select organizations' use -- on June 30. But before it was pulled, the Center for AI Safety (CAIS) tested Fable 5 on its Remote Labor Index (RLI), released in October 2025. It blew Anthropic's Opus 4.8 and OpenAI's GPT-5.5, each relatively new and considered impressive, out of the water.
Also: How to beat the AI algorithm and get the job of your dreams
RLI measures "how often AI agents can complete real, economically valuable freelance projects [...] at a quality a paying client would actually accept," CAIS explained in the study. These can include computer-assisted and graphic design, data analysis, video work, and more. As in other similar human ability tests, each deliverable the models create is evaluated by humans against a professional standard deliverable. The resulting automation rate reflects the distribution of projects where evaluators found what the AI produced to be as good as or better than human professional work.
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