In a recent LinkedIn post, Dan Sherrard Smith discusses the implications of Anthropic’s latest AI model, Fable 5, highlighting its groundbreaking ability to run autonomously for extended periods. This development, he suggests, marks a significant shift in AI capabilities, particularly for complex, long-duration tasks.
Smith points out that while many recent AI models perform similarly on short, simple tasks like drafting an email, they falter when faced with more demanding projects. He elaborates on the limitations of current models:
“On a long task e.g. research 50 competitors, build a 90-day content plan, process 18 months of client transcripts, most models lose the thread. They forget what they were doing five steps ago, repeat themselves, drift off-brief, or produce slop that needs heavy editing.”
The Advantage of Long-Horizon AI
According to Dan Sherrard Smith, Fable 5 is engineered to overcome these limitations. He explains that the model is designed to maintain focus across thousands of steps, remember its objectives, self-correct, and ensure accuracy. This capability, Smith argues, fundamentally changes the nature of tasks that can be delegated to AI.
For the past couple of years, AI has primarily accelerated tasks like typing, drafting, and basic research. While useful, these applications still required constant human oversight. Smith contrasts this with Fable 5’s potential:
“Hand it a project. And it will come back to the output.”
He emphasizes that this represents a new paradigm where AI can handle a project from initiation to completion, rather than just assisting with discrete steps.
Early Access Success Stories
Dan Sherrard Smith shares compelling evidence from early access users to underscore Fable 5’s performance. He notes that companies like Stripe have reportedly compressed months of engineering work into days using the new model. Furthermore, the CEO of Cursor is quoted as saying Fable 5 addresses “a class of long-horizon problems out of reach for earlier models.” Other benchmarks cited include a high score on a senior finance benchmark by Hebbia and strong performance in blind reviews by a legal team, where its redlines matched or surpassed their current model.
Balancing Capability with Restraint
A particularly interesting aspect highlighted by Smith is Fable 5’s safety architecture. He explains that the model is designed to detect sensitive requests in fields like cybersecurity, biology, and chemistry, and then hand them off to a more specialized model, Opus 4.8. While acknowledging that this can sometimes flag benign requests, Smith points out that 95% of sessions do not trigger this fallback mechanism.
“This is the part I find genuinely interesting. The most capable model in the world but with restraint engineered into the product.”
In Dan Sherrard Smith’s view, this combination of advanced capability and built-in safety measures is a significant innovation. He concludes by suggesting that users still relying on AI for simple, one-off prompts are essentially using 2024-level technology, implying that Fable 5 represents a more advanced frontier. He encourages readers to experiment with Fable 5, which is available on paid Claude plans until June 22.
📝 About This Content
This article is based on insights shared by Dan Sherrard Smith on LinkedIn.
📅 Originally posted on June 11, 2026 | View original post on LinkedIn →