GPT-5.6 Terra and Nova 2 Lite are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
GPT-5.6 Terra, from OpenAI, has a 1,050,000-token context window and is priced at $2/M tokens input, $12/M tokens output on OpenRouter.
Nova 2 Lite, from Amazon, has a 1,000,000-token context window and is priced at $0.30/M tokens input, $2.50/M tokens output on OpenRouter.