Anthropic released Fable 5 on June 9 and offered paid Claude subscribers a limited free trial. The model was briefly withdrawn, then returned July 1 with added safeguards. Free access was scheduled to end Sunday and has now been extended through Sunday while Anthropic adds computing capacity. After that, subscribers will need to buy credits to continue using it.

This appears to be the first time a major AI company has offered a frontier AI model as a metered add-on instead of including access in a monthly subscription. The change applies not only to Claude Pro subscribers paying $20 a month but also to users on the $100 and $200 Max plans..

If you use Claude to summarize an article, draft a letter, explain a Medicare benefit or plan a trip, the models already included with your subscription are more than capable. Fable is primarily aimed at programmers building large software projects, researchers analyzing hundreds of documents and professionals using AI agents to complete complex assignments with minimal human supervision. But there have been some imaginative applications that show how creative thinking can produce some very interesting results.

AI commentator Nate B. Jones recently described a user who connected months of Fitbit data with his meetings calendar and asked Fable to determine which people he met with caused his heart rate to spike. In minutes, Fable analyzed months of records and identified the colleagues who caused him the most stress. According to Nate, no other model can handle as much data in so little time.

But there is a tradeoff. In a recent column, I explained that AI measures its work in tokens, the small pieces of text it reads and generates. Large analytical jobs like these consume far more tokens than an ordinary conversation because the model repeatedly processes the information while working toward an answer.

Claude users were already reporting that they could exhaust their weekly allocations in about two days, including subscribers paying $100 or $200 a month, before Fable 5 arrived. During the trial, Fable use draws from those same limits and can consume them even faster because it is built for large, complex assignments. Once the trial ends, users who want to continue will have to purchase usage credits, with a minimum purchase of $50.

Anthropic says the separate charge is tied to limited computing capacity. In its announcement extending the trial, the company said it aims to restore Fable “as a standard part of subscription plans” once sufficient capacity is available.

That leaves open an important question. Will Fable eventually return at no additional charge under today’s subscription prices, or will plans become more expensive as advanced users consume more computing power? Anthropic has not said.

There is no indication that OpenAI plans to adopt this approach for ChatGPT, which currently offers more generous usage limits than Claude, at least for now.

Still, it exposes a problem every AI company faces: The most capable users consume vastly more computing power than everyone else. Charging separately for Fable may delay subscription increases, but it doesn’t eliminate the underlying cost. If frontier models continue to become more capable and more expensive to run, AI companies will eventually have to choose among raising subscription prices, tightening usage limits or charging separately for their most powerful models. Anthropic has chosen the third option first.

Today, Fable appeals to a relatively small group of advanced users. But that group will expand as more people learn to use AI beyond simple questions and writing tasks. A few years ago, asking AI to write computer code or create a presentation was as sophisticated as running a swarm of agents today. As AI skills become more common, so will demand for models that can tackle far more ambitious work.

Leslie Meredith has been writing about technology for more than a decade. As a mom of four, value, usefulness and online safety take priority. Have a question? Email Leslie at asklesliemeredith@gmail.com.