Build .NET MCP Tools with Azure Functions and Dataverse

dotnet add package Microsoft.Azure.Functions.Worker.Extensions.Mcp
dotnet add package Microsoft.Azure.Functions.Worker.ApplicationInsights
dotnet add package Microsoft.ApplicationInsights.WorkerService
dotnet add package Microsoft.PowerPlatform.Dataverse.Client

using Microsoft.Azure.Functions.Worker.Builder;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using SitecoreAI.Dataverse.Functions.Services;

var builder = FunctionsApplication.CreateBuilder(args);

builder.ConfigureFunctionsWebApplication();

builder.Services
    .AddApplicationInsightsTelemetryWorkerService()
    .ConfigureFunctionsApplicationInsights();

builder.Services.AddSingleton<IDataverseService, DataverseService>();

builder.Build().Run();

{
  "version": "2.0",
  "extensions": {
    "mcp": {
      "serverName": "DataverseEnquiryMcpServer",
      "serverVersion": "1.0.0",
      "instructions": "Use these tools only for approved customer-enquiry operations.",
      "system": {
        "webhookAuthorizationLevel": "System"
      }
    }
  }
}

[Function(nameof(CreateEnquiryTool))]
    public async Task<string> CreateEnquiryTool(
        [McpToolTrigger(
            "create_enquiry",
            "Creates a new customer enquiry record in Microsoft Dataverse.")]
        ToolInvocationContext context,
        [McpToolProperty("fullName", "The full name of the customer submitting the enquiry.", isRequired: true)]
        string fullName,
        [McpToolProperty("email", "Customer valid email address.", isRequired: true)]
        string email,
        [McpToolProperty("message", "The enquiry message or requirements body.", isRequired: true)]
        string message,
        [McpToolProperty("source", "The origin of the lead (e.g., 'SitecoreAI Form', 'AI Agent').", isRequired: false)]
        string? source = "MCP Agent",
        CancellationToken cancellationToken = default)
    {
        _logger.LogInformation("MCP Tool 'create_enquiry' invoked for customer: {Email}", email);

        var request = new CreateEnquiryRequest
        {
            Name = fullName,
            Email = email,
            Message = message,
            Source = source ?? "MCP Agent"
        };

        var recordId = await _dataverseService.CreateEnquiryAsync(request, cancellationToken);

        return System.Text.Json.JsonSerializer.Serialize(new
        {
            success = true,
            message = "Enquiry created successfully in Dataverse.",
            recordId = recordId.ToString()
        });
    }

    [Function(nameof(GetRecentEnquiriesTool))]
        public async Task<string> GetRecentEnquiriesTool(
            [McpToolTrigger(
            "get_recent_enquiries",
            "Retrieves a list of recent customer enquiry records from Dataverse.")]
        ToolInvocationContext context,
            [McpToolProperty("pageSize", "Number of enquiry records to return (1-100). Default is 10.", isRequired: false)]
        int pageSize = 10,
            CancellationToken cancellationToken = default)
        {
            var clampedSize = Math.Clamp(pageSize, 1, 100);
            _logger.LogInformation("MCP Tool 'get_recent_enquiries' invoked with pageSize: {Size}", clampedSize);

            var enquiries = await _dataverseService.GetEnquiriesAsync(clampedSize, cancellationToken);
            return System.Text.Json.JsonSerializer.Serialize(enquiries);
        }

 [Function(nameof(GetEnquiryByIdTool))]
    public async Task<string> GetEnquiryByIdTool(
        [McpToolTrigger(
            "get_enquiry_by_id",
            "Fetches a single enquiry record by its unique Dataverse GUID.")]
        ToolInvocationContext context,
        [McpToolProperty("enquiryId", "The GUID of the Dataverse enquiry record.", isRequired: true)]
        string enquiryId,
        CancellationToken cancellationToken = default)
    {
        if (!Guid.TryParse(enquiryId, out var idGuid))
        {
            return System.Text.Json.JsonSerializer.Serialize(new { error = "Invalid GUID format." });
        }

        var enquiry = await _dataverseService.GetEnquiryByIdAsync(idGuid, cancellationToken);
        if (enquiry is null)
        {
            return System.Text.Json.JsonSerializer.Serialize(new { error = $"Record with ID {enquiryId} not found." });
        }

        return System.Text.Json.JsonSerializer.Serialize(enquiry);
    }

dotnet clean
dotnet build
func start

MCP server endpoint: http://localhost:<PORT NUMBER>/runtime/webhooks/mcp

curl.exe -X POST "http://localhost:7232/runtime/webhooks/mcp" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 104,
    "method": "tools/call",
    "params": {
      "name": "create_enquiry",
      "arguments": {
        "fullName": "Priya Sharma",
        "email": "priya.sharma@cloudarchitects.com",
        "message": "Planning a migration to .NET Isolated Azure Functions with Key Vault secret references for Dataverse CRM integration.",
        "source": "Webinar"
      }
    }
  }'

{
  "servers": {
    "local-azure-functions-mcp": {
      "type": "sse",
      "url": "http://localhost:<PORT NUMBER>/runtime/webhooks/mcp"
    }
  }
}

# Publish Function App
func azure functionapp publish func-sitecoreai-dataverse-mcp-prod

{
  "servers": {
    "local-azure-functions-mcp": {
      "type": "sse",
      "url": "http://localhost:<PORT NUMBER>/runtime/webhooks/mcp"
    },
    "azure-functions-mcp": {
      "type": "sse",
      "url": "https://<YOUR HOST NAME>.azurewebsites.net/runtime/webhooks/mcp",
      "headers": {
        "x-functions-key": "functions-key"
      }
    }    
  },
  "inputs": []
}