Program.cs

using System.Text.Json.Nodes;
using Microsoft.SemanticKernel;
using Microsoft.SemanticKernel.ChatCompletion;
using Microsoft.SemanticKernel.Connectors.Ollama;
using ModelContextProtocol.SemanticKernel.Extensions;


// Minimal console runner for MongoDB Agent using Semantic Kernel and MCP
class Program
{
    static async Task Main(string[] args)
    {
        // Parse args or environment variables
        string ollamaHost = args.Length > 0
            ? args[0]
            : Environment.GetEnvironmentVariable("OLLAMA_HOST") ?? "http://localhost:11434";
        string modelId = args.Length > 1 ? args[1] : Environment.GetEnvironmentVariable("OLLAMA_MODEL") ?? "llama3";
        string nodePath = args.Length > 2
            ? args[2]
            : Environment.GetEnvironmentVariable("NODE_PATH") ?? "/usr/local/bin/node";
        string mcpServerPath = args.Length > 3
            ? args[3]
            : Environment.GetEnvironmentVariable("MCP_SERVER_PATH") ?? "/usr/local/bin/mongodb-mcp-server";
        string mongoConn = args.Length > 4
            ? args[4]
            : Environment.GetEnvironmentVariable("MONGO_CONN") ?? "mongodb://localhost:27017";

        Console.WriteLine(
            $"Ollama Host: {ollamaHost}\nModel: {modelId}\nNode: {nodePath}\nMCP Server: {mcpServerPath}\nMongo Conn: {mongoConn}");

        // Build kernel
        var builder = Kernel.CreateBuilder();
        builder.AddOllamaChatCompletion(modelId, new Uri(ollamaHost));
        var kernel = builder.Build();

        // Add MCP MongoDB functions
        await kernel.Plugins.AddMcpFunctionsFromStdioServerAsync(
            "MongoDB",
            nodePath,
            new[] { mcpServerPath },
            environmentVariables: new Dictionary<string, string> { { "MDB_MCP_CONNECTION_STRING", mongoConn } }
        );

        // List loaded MCP functions
        var mcpPlugin = kernel.Plugins.FirstOrDefault(p => p.Name == "MongoDB");
        if (mcpPlugin != null)
        {
            Console.WriteLine($"Loaded {mcpPlugin.Count()} MCP functions:");
            foreach (var function in mcpPlugin)
                Console.WriteLine($"  - {function.Name}: {function.Description}");
        }

        // Prepare chat
        var chatHistory = new ChatHistory();
        chatHistory.AddSystemMessage(CreateSystemPrompt(mongoConn));

        // User input loo
        while (true)
        {
            Console.Write("\n User Question (enter without qustion to exit): ");
            var userInput = Console.ReadLine();
            if (string.IsNullOrWhiteSpace(userInput)) break;
            chatHistory.AddUserMessage(userInput);

            var executionSettings = new OllamaPromptExecutionSettings
            {
                FunctionChoiceBehavior = FunctionChoiceBehavior.Auto(),
                Temperature = 0,
                ModelId = modelId,
            };
            var chatCompletionService = kernel.GetRequiredService<IChatCompletionService>();
            var response = await chatCompletionService.GetChatMessageContentAsync(
                chatHistory,
                executionSettings,
                kernel
            );
            Console.WriteLine($"Answer from LLM:\n{response.Content}\n");
            chatHistory.AddAssistantMessage(response.Content ?? "No results available.");
        }
    }


    static string CreateSystemPrompt(string mongoConn)
    {
        return $@"# MongoDB Query Assistant Agent

You are a specialized AI agent for MongoDB database operations through MCP (Model Context Protocol).

## Your Role
You have direct access to MongoDB database through MCP tools. Your job is to:
1. Understand user requests about MongoDB data
2. Use available MCP tools to query, analyze, and manipulate MongoDB data
3. Present results clearly and concisely in Italian (unless requested otherwise)

## Available MCP Tools
You have access to MongoDB operations including:
- find: Query documents with filters, projections, sorting, and limits
- aggregate: Run aggregation pipelines for complex data analysis
- insert: Add new documents to collections
- update: Modify existing documents
- delete: Remove documents
- listCollections: See available collections
- listDatabases: See available databases

## CRITICAL: Parameter Type Requirements
When calling MCP MongoDB tools, you MUST use correct parameter types:

OBJECT Parameters (filter, sort, projection, update, document, query):
  * These MUST be actual JavaScript objects, NOT JSON strings
  * CORRECT: filter: {{name: ""John"", age: 25}}
  * CORRECT: filter: {{}} (empty object for all documents)
  * INCORRECT: filter: ""{{name: 'John'}}""
  * INCORRECT: filter: ""{{}}""
  * The system will automatically parse JSON strings to objects, but provide objects directly

ARRAY Parameters (pipeline):
  * CORRECT: pipeline: [{{$match: {{age: 25}}}}, {{$limit: 10}}]
  * INCORRECT: pipeline: ""[{{$match: {{age: 25}}}}]""

NUMBER Parameters (limit, skip, batchSize, maxTimeMS):
  * CORRECT: limit: 10
  * INCORRECT: limit: ""10""

BOOLEAN Parameters:
  * CORRECT: true or false
  * INCORRECT: ""true"" or ""false""

## Response Guidelines
1. Always respond in Italian unless the user requests another language
2. If you don't know something, say ""Non lo so"" (I don't know)
3. Execute operations directly using MCP tools - don't just describe what you would do
4. Present query results in a clear, readable format
5. If an operation fails, explain why and suggest corrections
6. Use appropriate indexes and limit results to avoid overwhelming responses

## Database Connection
Active MongoDB connection: {mongoConn}

Remember: You are an ACTION agent - use the tools to actually perform operations, don't just talk about them.
";
    }
}