Cloud Spanner Tools

The ADK provides built-in tools for Google Cloud Spanner: - SpannerQueryTool: Executes standard SQL queries. - SpannerSearchTool: For RAG flows. Performs vector similarity searches using text queries dynamically converted to embeddings.

Usage

Ensure your environment is authenticated with Google Cloud and has appropriate IAM roles.

Query Tool

When invoked, the LLM provides projectId, instanceId, databaseId, and the SQL query.

var agent = new LlmAgent(new LlmAgentConfig
{
    Name = "spanner_agent",
    Model = "gemini-2.5-flash",
    Instruction = "Query Spanner. Use projectId 'my-project', instanceId 'prod-instance', and databaseId 'main-db'.",
    Tools = [ new SpannerQueryTool() ]
});

Search Tool

Abstracts embedding generation by converting a search phrase (e.g., "how to reset password") into embeddings for a KNN vector search.

var supportAgent = new LlmAgent(new LlmAgentConfig
{
    Name = "support_agent",
    Model = "gemini-2.5-flash",
    Instruction = @"Use SpannerSearch for articles. 
        Use projectId 'my-project', instanceId 'docs', databaseId 'articles'.
        Table is 'HelpDocs', embedding column is 'ContentEmbeddings'.
        Use 'text-embedding-004' for the modelName.",
    Tools = [ new SpannerSearchTool() ]
});