agent-framework/dotnet/samples/GettingStarted/FoundryAgents/FoundryAgents_Step18_FileSearch/Program.cs

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

// This sample shows how to use File Search Tool with AI Agents.

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

string endpoint = Environment.GetEnvironmentVariable("AZURE_FOUNDRY_PROJECT_ENDPOINT") ?? throw new InvalidOperationException("AZURE_FOUNDRY_PROJECT_ENDPOINT is not set.");
string deploymentName = Environment.GetEnvironmentVariable("AZURE_FOUNDRY_PROJECT_DEPLOYMENT_NAME") ?? "gpt-4o-mini";

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

// Get a client to create/retrieve/delete server side agents with Azure Foundry Agents.
// 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}");

AIAgent agent = await CreateAgentWithMEAI();
// AIAgent agent = await CreateAgentWithNativeSDK();

// 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.
Console.WriteLine("\n--- Cleanup ---");
await aiProjectClient.Agents.DeleteAgentAsync(agent.Name);
await vectorStoresClient.DeleteVectorStoreAsync(vectorStoreId);
await filesClient.DeleteFileAsync(uploadedFile.Id);
File.Delete(searchFilePath);
Console.WriteLine("Cleanup completed successfully.");

// --- Agent Creation Options ---

#pragma warning disable CS8321 // Local function is declared but never used
// Option 1 - Using HostedFileSearchTool (MEAI + AgentFramework)
async Task<AIAgent> CreateAgentWithMEAI()
{
    return await aiProjectClient.CreateAIAgentAsync(
        model: deploymentName,
        name: "FileSearchAgent-MEAI",
        instructions: AgentInstructions,
        tools: [new HostedFileSearchTool() { Inputs = [new HostedVectorStoreContent(vectorStoreId)] }]);
}

// Option 2 - Using PromptAgentDefinition with ResponseTool.CreateFileSearchTool (Native SDK)
async Task<AIAgent> CreateAgentWithNativeSDK()
{
    return await aiProjectClient.CreateAIAgentAsync(
        name: "FileSearchAgent-NATIVE",
        creationOptions: new AgentVersionCreationOptions(
            new PromptAgentDefinition(model: deploymentName)
            {
                Instructions = AgentInstructions,
                Tools = {
                    ResponseTool.CreateFileSearchTool(vectorStoreIds: [vectorStoreId])
                }
            })
    );
}