OpenRouter Launches Fusion API Matching Claude Fable 5 at Half Cost on June 12

According to OpenRouter, the company launched Fusion API on June 12, a server-side service that combines multiple budget AI models to match Claude Fable 5 performance at roughly half the cost. On Perplexity's DRACO benchmark, a panel combining Gemini 3 Flash, Kimi K2.6, and DeepSeek V4 Pro achieved 64.7%, staying within 1 point of Fable 5's 69% while reducing expenses by approximately 50%. Fusion works by sending prompts to multiple models in parallel, then using a judge model to identify consensus and contradictions before a synthesizer generates the final answer.

The launch coincides with U.S. export control restrictions that forced Anthropic to suspend Fable 5 and Mythos 5 globally. OpenRouter positioned Fusion as a cost-effective alternative, announcing the product on X the day after Anthropic's suspension with the tagline "Fable-level intelligence at half the price."