Arena.ai Adds Claude Fable 5.1 to Direct Mode

The official Arena.ai account posted that users can test Claude Fable 5.1 by AnthropicAI directly in the platform. The post instructs followers to enter Direct Mode and pick the model from the dropdown menu. Access in Direct Mode runs only until Sept. 5 at 8am PT. The model stays available afterward in Battle Mode and Agent Mode. Arena.ai describes itself as a startup that runs community-driven LLM leaderboards and AI evaluations. The message tags the Claude account and includes a static promotional graphic on a black background.