Claude Fable 5.1 and DeepSeek V4 Pro 0813 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.
DeepSeek V4 Pro 0813, from DeepSeek, has a 1,048,576-token context window and is priced at $0.5808/M tokens input, $1.742/M tokens output on OpenRouter.