OpenRouter Launches Fusion API Matching Fable 5 Performance at Half Cost as Anthropic Suspends Model

According to OpenRouter, the company launched Fusion on June 12, a server-side API that sends prompts to multiple AI models in parallel, then uses a judge model and synthesizer to merge results into a single answer. On Perplexity's DRACO benchmark, a budget panel combining Gemini 3 Flash with open-source models Kimi K2.6 and DeepSeek V4 Pro, synthesized by Claude Opus 4.8, achieved 64.7% performance—within 1% of Fable 5 at roughly half the cost and outperforming solo GPT-5.5 (60%) and Opus 4.8 (58.8%).

The timing coincides with a U.S. export control directive that forced Anthropic to suspend Fable 5 and Mythos 5 for foreign nationals worldwide. OpenRouter positioned Fusion as "Fable-level intelligence at half the price" to address the gap created by the suspension.