Claude Opus 4.5 and Hermes 4 405B are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
Claude Opus 4.5, from Anthropic, has a 200,000-token context window and is priced at $5/M tokens input, $25/M tokens output on OpenRouter.
Hermes 4 405B, from Nous Research, has a 131,072-token context window and is priced at $1/M tokens input, $3/M tokens output on OpenRouter.