Compare Claude Fable 5.1 from Anthropic and Union Alpha from Stealth on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the OpenRouter API.
Claude Fable 5.1 and Union Alpha are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
Claude Fable 5.1, from Anthropic, has a 1,000,000-token context window and is priced at $10/M tokens input, $50/M tokens output on OpenRouter.
Union Alpha, from Stealth, has a 262,144-token context window and is free to use on OpenRouter.