Claude Opus 5 and Granite 4.2 8B are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
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.
Granite 4.2 8B, from ibm-granite, has a 131,072-token context window and is priced at $0.10/M tokens input, $0.15/M tokens output on OpenRouter.