Vertex AI RAG Retrieval Tool

Gemini & Vertex AI Only

This tool leverages Google Cloud's Retrieval Config API and is exclusively compatible with Gemini models on Vertex AI.

The VertexAiRagRetrievalTool integrates deeply with Google Cloud's Vertex AI to perform Retrieval-Augmented Generation (RAG).

Overview

Unlike standard function-calling tools, this tool leverages the RetrievalConfig of the Gemini generation API. The Gemini backend automatically queries your specified Vertex AI Data Stores or RAG Corpora during text generation, returning rich GroundingMetadata.

Usage

Configure the tool by specifying data stores or corpora for the backend to retrieve from:

using GoogleAdk.Core.Abstractions.Models;
using GoogleAdk.Core.Agents;
using GoogleAdk.Core.Tools;

var ragTool = new VertexAiRagRetrievalTool(
    ragResources: [
        new VertexAiSearchDataStoreSpec { DataStore = "projects/my-project/locations/global/collections/default_collection/dataStores/my-docs" }
    ],
    // ragCorpora: ["projects/my-project/locations/us-central1/ragCorpora/1234567890"],
    similarityTopK: 5,
    vectorDistanceThreshold: 0.3
);

var agent = new LlmAgent(new LlmAgentConfig
{
    Name = "rag_agent",
    Model = "gemini-2.5-pro",
    Instruction = "Answer based on the provided RAG context.",
    Tools = [ragTool]
});