Improve ChatQuery description readability

Demo/DemoChat/Sources/ResponsesStore.swift

@@ -656,6 +656,8 @@ public final class ResponsesStore: ObservableObject {
         case .mcpToolCall(_ /* let mcpCall */):
             // MCP tool call in progress - no UI action needed
             break
+        case .reasoning(let reasoningItem):
+            print("reasoning output item added, summary: \(reasoningItem.summary)")
         default:
             throw StoreError.unhandledOutputItem(outputItem)
         }
@@ -693,6 +695,8 @@ public final class ResponsesStore: ObservableObject {
             if let output = mcpCall.output {
                 print("Result: \(output)")
             }
+        case .reasoning(let reasoningItem):
+            print("reasoning output item done, summary: \(reasoningItem.summary)")
         default:
             throw StoreError.unhandledOutputItem(outputItem)
         }

Sources/OpenAI/Private/ChatQuery+CustomStringConvertible.swift

@@ -0,0 +1,31 @@
+//
+//  ChatQuery+CustomStringConvertible.swift
+//  OpenAI
+//
+//  Created by Oleksii Nezhyborets on 19.11.2025.
+//
+
+import Foundation
+
+extension ChatQuery: CustomStringConvertible, CustomDebugStringConvertible {
+
+    public var description: String { jsonDescription(prettyPrinted: true) }
+
+    public var debugDescription: String { jsonDescription(prettyPrinted: true) }
+
+    private func jsonDescription(prettyPrinted: Bool) -> String {
+        let encoder = JSONEncoder()
+        var formatting: JSONEncoder.OutputFormatting = [.sortedKeys]
+        if prettyPrinted {
+            formatting.insert(.prettyPrinted)
+        }
+        encoder.outputFormatting = formatting
+        guard
+            let data = try? encoder.encode(self),
+            let string = String(data: data, encoding: .utf8)
+        else {
+            return "ChatQuery(model: \(model), messages: \(messages.count))"
+        }
+        return string
+    }
+}