Riley Brown demos Claude Fable 5 building a Lovable clone in two prompts
In an episode of Agent Native, Riley Brown showcases Claude Fable 5 — a new "Mythos class" model from Anthropic released on June 9, 2026 — by building a clone of the Lovable mobile app in two prompts and open-sourcing the result.
Score breakdown
Fable 5 introduces a new model tier above Opus, and Brown's two-prompt Lovable clone demo illustrates a concrete reduction in the effort required to build functional, visually polished web apps with AI agents.
- 01Anthropic released Claude Fable 5 on June 9, 2026, described as a 'Mythos class' model above Opus in capability.
- 02Fable 5 is described as a modified version of Claude Mythos with safeguards added for general use.
- 03Brown built a clone of the Lovable mobile app in two prompts using Fable 5 and open-sourced it on GitHub as 'Rilable'.
Riley Brown's Agent Native episode focuses entirely on Anthropic's release of Claude Fable 5, a model Brown describes as belonging to a new "Mythos class" — a tier above the existing Opus, Sonnet, and Haiku lineup that has been in place since mid-2024. Released on June 9, 2026, Fable 5 is characterized as a modified version of Claude Mythos with additional safeguards for general use. Brown reports that based on his own three days of use, the model excels at tool use, sustains tool calls for longer durations, and demonstrates stronger spatial and visual reasoning than prior models.
He also demonstrates Fable 5 recreating a McKinsey research deck on a different topic with near-identical visual fidelity.
Brown's headline demo involves building a functional clone of the Lovable mobile app using just two prompts — first providing the app's design via screenshots, then issuing a single build instruction — and running it in a sandbox environment. He open-sourced this clone, dubbed "Rilable," on GitHub. He also demonstrates Fable 5 recreating a McKinsey research deck on a different topic with near-identical visual fidelity. The episode goes on to discuss what Brown frames as a "building block economy" for AI agents enabled by Mythos-class models, as well as the model's limitations and how long it will remain available within the Claude app before transitioning to API pricing after June 22nd.
Key facts
- 01Anthropic released Claude Fable 5 on June 9, 2026, described as a 'Mythos class' model above Opus in capability.
- 02Fable 5 is described as a modified version of Claude Mythos with safeguards added for general use.
- 03Brown built a clone of the Lovable mobile app in two prompts using Fable 5 and open-sourced it on GitHub as 'Rilable'.
- 04Brown demonstrated Fable 5 recreating a McKinsey research deck on a different topic with near-identical visual fidelity.
- 05Fable 5 is currently included in existing Claude plans but will shift to API pricing after June 22nd.
- 06Brown describes Fable 5 as notably stronger at tool use, spatial reasoning, and visual tasks compared to prior models.
Topics
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