Implementation of Custom Tool in MCP

src/Azure.DataApiBuilder.Mcp/Core/CustomMcpToolFactory.cs

@@ -0,0 +1,65 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using Azure.DataApiBuilder.Config.ObjectModel;
+using Azure.DataApiBuilder.Mcp.Model;
+using Microsoft.Extensions.Logging;
+
+namespace Azure.DataApiBuilder.Mcp.Core
+{
+    /// <summary>
+    /// Factory for creating custom MCP tools from stored procedure entity configurations.
+    /// Scans runtime configuration and generates dynamic tools for entities marked with custom-tool enabled.
+    /// </summary>
+    public class CustomMcpToolFactory
+    {
+        /// <summary>
+        /// Creates custom MCP tools from entities configured with "mcp": { "custom-tool": true }.
+        /// </summary>
+        /// <param name="config">The runtime configuration containing entity definitions.</param>
+        /// <param name="logger">Optional logger for diagnostic information.</param>
+        /// <returns>Enumerable of custom tools generated from configuration.</returns>
+        public static IEnumerable<IMcpTool> CreateCustomTools(RuntimeConfig config, ILogger? logger = null)
+        {
+            if (config?.Entities == null)
+            {
+                logger?.LogWarning("No entities found in runtime configuration for custom tool generation.");
+                return Enumerable.Empty<IMcpTool>();
+            }
+
+            List<IMcpTool> customTools = new();
+            int customToolCount = 0;
+
+            foreach ((string entityName, Entity entity) in config.Entities)
+            {
+                // Filter: Only stored procedures with custom-tool enabled
+                if (entity.Source.Type == EntitySourceType.StoredProcedure &&
+                    entity.Mcp?.CustomToolEnabled == true)
+                {
+                    try
+                    {
+                        DynamicCustomTool tool = new(entityName, entity);
+                        customToolCount++;
+
+                        logger?.LogInformation(
+                            "Created custom MCP tool '{ToolName}' for stored procedure entity '{EntityName}'",
+                            tool.GetToolMetadata().Name,
+                            entityName);
+
+                        customTools.Add(tool);
+                    }
+                    catch (Exception ex)
+                    {
+                        logger?.LogError(
+                            ex,
+                            "Failed to create custom tool for entity '{EntityName}'. Skipping.",
+                            entityName);
+                    }
+                }
+            }
+
+            logger?.LogInformation("Custom MCP tool generation complete. Created {Count} custom tools.", customToolCount);
+            return customTools;
+        }
+    }
+}