agent-framework/dotnet/samples/02-agents/AgentsWithFoundry/Agent_Step16_FileSearch/Program.cs

// Copyright (c) Microsoft. All rights reserved.

// This sample shows how to use File Search Tool with a ChatClientAgent.

using Azure.AI.Projects;
using Azure.Identity;
using Microsoft.Agents.AI;
using Microsoft.Extensions.AI;
using OpenAI.Assistants;
using OpenAI.Files;

string endpoint = Environment.GetEnvironmentVariable("FOUNDRY_PROJECT_ENDPOINT") ?? throw new InvalidOperationException("FOUNDRY_PROJECT_ENDPOINT is not set.");
string deploymentName = Environment.GetEnvironmentVariable("FOUNDRY_MODEL") ?? "gpt-5.4-mini";

const string AgentInstructions = "You are a helpful assistant that can search through uploaded files to answer questions.";

// We need the AIProjectClient to upload files and create vector stores.
// WARNING: DefaultAzureCredential is convenient for development but requires careful consideration in production.
// In production, consider using a specific credential (e.g., ManagedIdentityCredential) to avoid
// latency issues, unintended credential probing, and potential security risks from fallback mechanisms.
AIProjectClient aiProjectClient = new(new Uri(endpoint), new DefaultAzureCredential());
var projectOpenAIClient = aiProjectClient.GetProjectOpenAIClient();
var filesClient = projectOpenAIClient.GetProjectFilesClient();
var vectorStoresClient = projectOpenAIClient.GetProjectVectorStoresClient();

// 1. Create a temp file with test content and upload it.
string searchFilePath = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName() + "_lookup.txt");
File.WriteAllText(
    path: searchFilePath,
    contents: """
        Employee Directory:
        - Alice Johnson, 28 years old, Software Engineer, Engineering Department
        - Bob Smith, 35 years old, Sales Manager, Sales Department
        - Carol Williams, 42 years old, HR Director, Human Resources Department
        - David Brown, 31 years old, Customer Support Lead, Support Department
        """
);

Console.WriteLine($"Uploading file: {searchFilePath}");
OpenAIFile uploadedFile = filesClient.UploadFile(
    filePath: searchFilePath,
    purpose: FileUploadPurpose.Assistants
);
Console.WriteLine($"Uploaded file, file ID: {uploadedFile.Id}");

// 2. Create a vector store with the uploaded file.
var vectorStoreResult = await vectorStoresClient.CreateVectorStoreAsync(
    options: new() { FileIds = { uploadedFile.Id }, Name = "EmployeeDirectory_VectorStore" }
);
string vectorStoreId = vectorStoreResult.Value.Id;
Console.WriteLine($"Created vector store, vector store ID: {vectorStoreId}");

// Create a AIAgent with HostedFileSearchTool.
AIAgent agent = aiProjectClient.AsAIAgent(deploymentName,
    instructions: AgentInstructions,
    name: "FileSearchAgent-RAPI",
    tools: [new HostedFileSearchTool() { Inputs = [new HostedVectorStoreContent(vectorStoreId)] }]);

// Run the agent
Console.WriteLine("\n--- Running File Search Agent ---");
AgentResponse response = await agent.RunAsync("Who is the youngest employee?");
Console.WriteLine($"Response: {response}");

// Getting any file citation annotations generated by the tool
foreach (AIAnnotation annotation in response.Messages.SelectMany(m => m.Contents).SelectMany(c => c.Annotations ?? []))
{
    if (annotation.RawRepresentation is TextAnnotationUpdate citationAnnotation)
    {
        Console.WriteLine($$"""
            File Citation:
              File Id: {{citationAnnotation.OutputFileId}}
              Text to Replace: {{citationAnnotation.TextToReplace}}
            """);
    }
}

// Cleanup file resources.
Console.WriteLine("\n--- Cleanup ---");
await vectorStoresClient.DeleteVectorStoreAsync(vectorStoreId);
await filesClient.DeleteFileAsync(uploadedFile.Id);
File.Delete(searchFilePath);
Console.WriteLine("Cleanup completed successfully.");