Nex-N2-Mini and Claude Fable 5 are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
Nex-N2-Mini, from nex-agi, has a 262,144-token context window and is priced at $0.025/M tokens input, $0.10/M tokens output on OpenRouter.
Claude Fable 5, from Anthropic, has a 1,000,000-token context window and is priced at $10/M tokens input, $50/M tokens output on OpenRouter.