Completion support (#15)

src/mcpdotnet/Protocol/Types/Argument.cs

@@ -0,0 +1,15 @@
+using System.Text.Json.Serialization;
+
+namespace McpDotNet.Protocol.Types;
+
+/// <summary>
+/// Used for completion requests to provide additional context for the completion options.
+/// </summary>
+public class Argument
+{
+    [JsonPropertyName("name")]
+    public string Name { get; set; } = string.Empty;
+
+    [JsonPropertyName("value")]
+    public string Value { get; set; } = string.Empty;
+}

src/mcpdotnet/Protocol/Types/Completion.cs

@@ -0,0 +1,27 @@
+using System.Text.Json.Serialization;
+
+namespace McpDotNet.Protocol.Types;
+
+/// <summary>
+/// Represents a completion object in the server's response.
+/// </summary>
+public class Completion
+{
+    /// <summary>
+    /// An array of completion values. Must not exceed 100 items.
+    /// </summary>
+    [JsonPropertyName("values")]
+    public string[] Values { get; set; } = new string[0];
+
+    /// <summary>
+    /// The total number of completion options available. This can exceed the number of values actually sent in the response.
+    /// </summary>
+    [JsonPropertyName("total")]
+    public int? Total { get; set; }
+
+    /// <summary>
+    /// Indicates whether there are additional completion options beyond those provided in the current response, even if the exact total is unknown.
+    /// </summary>
+    [JsonPropertyName("hasMore")]
+    public bool? HasMore { get; set; }
+}

src/mcpdotnet/Protocol/Types/Reference.cs

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+using System.Text.Json.Serialization;
+
+namespace McpDotNet.Protocol.Types;
+
+/// <summary>
+/// Represents a reference to a resource or prompt. Umbrella type for both ResourceReference and PromptReference from the spec schema.
+/// </summary>
+public class Reference
+{
+    /// <summary>
+    /// The type of content. Can be ref/resource or ref/prompt.
+    /// </summary>
+    [JsonPropertyName("type")]
+    public string Type { get; set; } = string.Empty;
+
+    [JsonPropertyName("uri")]
+    public string? Uri { get; set; }
+
+    [JsonPropertyName("name")]
+    public string? Name { get; set; }
+
+    /// <summary>
+    /// Returns a string representation of the reference.
+    /// </summary>
+    public override string ToString()
+    {
+        return $"\"{Type}\": \"{Uri ?? Name}\"";
+    }
+
+    /// <summary>
+    /// Validates the reference object.
+    /// </summary>
+    public bool Validate(out string validationMessage)
+    {
+        if (Type == "ref/resource")
+        {
+            if (string.IsNullOrEmpty(Uri))
+            {
+                validationMessage = "Uri is required for ref/resource";
+                return false;
+            }
+        }
+        else if (Type == "ref/prompt")
+        {
+            if (string.IsNullOrEmpty(Name))
+            {
+                validationMessage = "Name is required for ref/prompt";
+                return false;
+            }
+        }
+        else
+        {
+            validationMessage = $"Unknown reference type: {Type}";
+            return false;
+        }
+
+        validationMessage = string.Empty;
+        return true;
+    }
+}
+
+/// <summary>
+/// The server's response to a completion/complete request
+/// </summary>
+public class CompleteResult
+{
+    [JsonPropertyName("completion")]
+    public Completion Completion { get; set; } = new Completion();
+}