Compare Union Alpha from Stealth and Claude Opus 5 from Anthropic on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the OpenRouter API.
Union Alpha and Claude Opus 5 are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
Union Alpha, from Stealth, has a 262,144-token context window and is free to use on OpenRouter.
Claude Opus 5, from Anthropic, has a 1,000,000-token context window and is priced at $5/M tokens input, $25/M tokens output on OpenRouter.