[ChatVertexAI](https://js.langchain.com/docs/integrations/chat/google_vertex_ai/): LLM should read this page when (setting up Google Vertex AI chat models in LangChain, implementing tool calling with Google Search retrieval, or configuring context caching with Vertex AI) (ChatVertexAI provides integration with Google's Vertex AI service for accessing models like Gemini. The page covers setup, credentials, invocation examples, tool calling with Google Search retrieval, context caching, and model chaining. It details model features including tool calling, structured output, multimodal inputs, and token usage tracking.)

