Change type of Tool.InputSchema to be JsonElement (#4)

* Change type of Tool.InputSchema to be JsonElement

* Add schema validation in the InputSchema property setter.

* Simplify AIFunction tool adapter.

---------

Co-authored-by: Eirik Tsarpalis <eirik.tsarpalis@gmail.com>

src/ModelContextProtocol/Protocol/Types/JsonSchema.cs

@@ -1,26 +0,0 @@
-namespace ModelContextProtocol.Protocol.Types;
-
-/// <summary>
-/// Represents a JSON schema for a tool's input arguments.
-/// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
-/// </summary>
-public class JsonSchema
-{
-    /// <summary>
-    /// The type of the schema, should be "object".
-    /// </summary>
-    [System.Text.Json.Serialization.JsonPropertyName("type")]
-    public string Type { get; set; } = "object";
-
-    /// <summary>
-    /// Map of property names to property definitions.
-    /// </summary>
-    [System.Text.Json.Serialization.JsonPropertyName("properties")]
-    public Dictionary<string, JsonSchemaProperty>? Properties { get; set; }
-
-    /// <summary>
-    /// List of required property names.
-    /// </summary>
-    [System.Text.Json.Serialization.JsonPropertyName("required")]
-    public List<string>? Required { get; set; }
-}

src/ModelContextProtocol/Protocol/Types/JsonSchemaProperty.cs

@@ -1,20 +0,0 @@
-namespace ModelContextProtocol.Protocol.Types;
-
-/// <summary>
-/// Represents a property in a JSON schema.
-/// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
-/// </summary>
-public class JsonSchemaProperty
-{
-    /// <summary>
-    /// The type of the property. Should be a JSON Schema type and is required.
-    /// </summary>
-    [System.Text.Json.Serialization.JsonPropertyName("type")]
-    public string Type { get; set; } = string.Empty;
-
-    /// <summary>
-    /// A human-readable description of the property.
-    /// </summary>
-    [System.Text.Json.Serialization.JsonPropertyName("description")]
-    public string? Description { get; set; } = string.Empty;
-}

src/ModelContextProtocol/Protocol/Types/Tool.cs

@@ -1,4 +1,6 @@
-using System.Text.Json.Serialization;
+using ModelContextProtocol.Utils.Json;
+using System.Text.Json;
+using System.Text.Json.Serialization;
 
 namespace ModelContextProtocol.Protocol.Types;
 
@@ -23,6 +25,23 @@ public class Tool
     /// <summary>
     /// A JSON Schema object defining the expected parameters for the tool.
     /// </summary>
+    /// <remarks>
+    /// Needs to a valid JSON schema object that additionally is of type object.
+    /// </remarks>
     [JsonPropertyName("inputSchema")]
-    public JsonSchema? InputSchema { get; set; }
+    public JsonElement InputSchema 
+    { 
+        get => _inputSchema; 
+        set
+        {
+            if (!McpJsonUtilities.IsValidMcpToolSchema(value))
+            {
+                throw new ArgumentException("The specified document is not a valid MPC tool JSON schema.", nameof(InputSchema));
+            }
+
+            _inputSchema = value;
+        }
+    }
+
+    private JsonElement _inputSchema = McpJsonUtilities.DefaultMcpToolSchema;
 }