Clean up namespaces (#410)

No meaningful code changes, just lots of namespace shuffling to have fewer namespaces and to put things in better namespaces.

src/ModelContextProtocol/Protocol/CallToolResponse.cs

@@ -0,0 +1,41 @@
+using System.Text.Json.Serialization;
+
+namespace ModelContextProtocol.Protocol;
+
+/// <summary>
+/// Represents the result of a <see cref="RequestMethods.ToolsCall"/> request from a client to invoke a tool provided by the server.
+/// </summary>
+/// <remarks>
+/// <para>
+/// Any errors that originate from the tool should be reported inside the result
+/// object, with <see cref="IsError"/> set to true, rather than as a <see cref="JsonRpcError"/>.
+/// </para>
+/// <para>
+/// However, any errors in finding the tool, an error indicating that the
+/// server does not support tool calls, or any other exceptional conditions,
+/// should be reported as an MCP error response.
+/// </para>
+/// <para>
+/// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
+/// </para>
+/// </remarks>
+public class CallToolResponse
+{
+    /// <summary>
+    /// Gets or sets the response content from the tool call.
+    /// </summary>
+    [JsonPropertyName("content")]
+    public List<Content> Content { get; set; } = [];
+
+    /// <summary>
+    /// Gets or sets an indication of whether the tool call was unsuccessful.
+    /// </summary>
+    /// <remarks>
+    /// When set to <see langword="true"/>, it signifies that the tool execution failed.
+    /// Tool errors are reported with this property set to <see langword="true"/> and details in the <see cref="Content"/>
+    /// property, rather than as protocol-level errors. This allows LLMs to see that an error occurred
+    /// and potentially self-correct in subsequent requests.
+    /// </remarks>
+    [JsonPropertyName("isError")]
+    public bool IsError { get; set; }
+}