feat(swift-host): add structuredContent support + JS console logging

- Use client.send() directly to get full CallTool.Result including structuredContent
  (the SDK's callTool() helper drops structuredContent)
- Add Value.toAny() extension to convert MCP Value to Any for AnyCodable
- Update ToolResult to include structuredContent field
- Pass structuredContent to AppBridge.sendToolResult() when present
- Add WKScriptMessageHandler to capture JavaScript console.log/error/warn
  from WebView and output as [JS LOG/ERROR/WARN] messages

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: ochafik

examples/basic-host-swift/Sources/BasicHostApp/McpHostViewModel.swift

@@ -6,6 +6,22 @@ import os.log
 
 private let logger = Logger(subsystem: "com.example.BasicHostSwift", category: "ToolCall")
 
+// Helper extension to convert MCP Value to Any for use with AnyCodable
+extension Value {
+    func toAny() -> Any {
+        switch self {
+        case .null: return NSNull()
+        case .bool(let b): return b
+        case .int(let i): return i
+        case .double(let d): return d
+        case .string(let s): return s
+        case .data(_, let d): return d.base64EncodedString()
+        case .array(let arr): return arr.map { $0.toAny() }
+        case .object(let dict): return dict.mapValues { $0.toAny() }
+        }
+    }
+}
+
 /// View model managing MCP server connection and tool execution.
 @MainActor
 class McpHostViewModel: ObservableObject {
@@ -282,6 +298,7 @@ enum ConnectionState: Equatable {
 /// Tool result type matching MCP SDK's callTool return
 struct ToolResult {
     let content: [Tool.Content]
+    let structuredContent: Value?
     let isError: Bool?
 }
 
@@ -333,8 +350,14 @@ class ToolCallInfo: ObservableObject, Identifiable {
                 return nil
             }
 
-            let (content, isError) = try await client.callTool(name: tool.name, arguments: arguments)
-            self.result = ToolResult(content: content, isError: isError)
+            // Use send() directly to get full result including structuredContent
+            let request = CallTool.request(.init(name: tool.name, arguments: arguments))
+            let callResult = try await client.send(request)
+            self.result = ToolResult(
+                content: callResult.content,
+                structuredContent: callResult.structuredContent,
+                isError: callResult.isError
+            )
 
             if let uiResourceUri = getUiResourceUri(from: tool) {
                 state = .loadingUi
@@ -407,12 +430,10 @@ class ToolCallInfo: ObservableObject, Identifiable {
         }
 
         bridge.onMessage = { role, content in
-            print("[Host] Message from Guest UI: \(role)")
             return McpUiMessageResult(isError: false)
         }
 
         bridge.onOpenLink = { url in
-            print("[Host] Open link request: \(url)")
             if let urlObj = URL(string: url) {
                 await MainActor.run {
                     UIApplication.shared.open(urlObj)
@@ -422,11 +443,10 @@ class ToolCallInfo: ObservableObject, Identifiable {
         }
 
         bridge.onLoggingMessage = { level, data, logger in
-            print("[Host] Guest UI log [\(level)]: \(data.value)")
+            // Guest UI logs can be captured here if needed
         }
 
         bridge.onSizeChange = { [weak self] width, height in
-            print("[Host] Size change: \(width ?? 0) x \(height ?? 0)")
             if let height = height {
                 Task { @MainActor in
                     self?.preferredHeight = CGFloat(height)
@@ -495,10 +515,14 @@ class ToolCallInfo: ObservableObject, Identifiable {
                 return nil
             }
         }
-        let params: [String: AnyCodable] = [
+        var params: [String: AnyCodable] = [
             "content": AnyCodable(contentDicts),
             "isError": AnyCodable(result.isError ?? false)
         ]
+        // Include structuredContent if present
+        if let sc = result.structuredContent {
+            params["structuredContent"] = AnyCodable(sc.toAny())
+        }
         try await bridge.sendToolResult(params)
     }
 

examples/basic-host-swift/Sources/BasicHostApp/WebViewContainer.swift

@@ -20,6 +20,32 @@ struct WebViewContainer: UIViewRepresentable {
         // Enable JavaScript
         configuration.preferences.javaScriptEnabled = true
 
+        // Add console log handler
+        let contentController = configuration.userContentController
+        contentController.add(context.coordinator, name: "consoleLog")
+
+        // Inject console override script
+        let consoleScript = WKUserScript(source: """
+            (function() {
+                var originalLog = console.log;
+                var originalError = console.error;
+                var originalWarn = console.warn;
+                console.log = function() {
+                    originalLog.apply(console, arguments);
+                    window.webkit.messageHandlers.consoleLog.postMessage({level: 'log', args: Array.from(arguments).map(String)});
+                };
+                console.error = function() {
+                    originalError.apply(console, arguments);
+                    window.webkit.messageHandlers.consoleLog.postMessage({level: 'error', args: Array.from(arguments).map(String)});
+                };
+                console.warn = function() {
+                    originalWarn.apply(console, arguments);
+                    window.webkit.messageHandlers.consoleLog.postMessage({level: 'warn', args: Array.from(arguments).map(String)});
+                };
+            })();
+            """, injectionTime: .atDocumentStart, forMainFrameOnly: false)
+        contentController.addUserScript(consoleScript)
+
         // Create web view
         let webView = WKWebView(frame: .zero, configuration: configuration)
         webView.scrollView.isScrollEnabled = true
@@ -104,10 +130,21 @@ struct WebViewContainer: UIViewRepresentable {
         Coordinator()
     }
 
-    /// Coordinator to handle WebView navigation
-    class Coordinator: NSObject, WKNavigationDelegate {
+    /// Coordinator to handle WebView navigation and console logging
+    class Coordinator: NSObject, WKNavigationDelegate, WKScriptMessageHandler {
         var hasLoadedContent = false
 
+        // Handle console log messages from JavaScript
+        func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
+            if message.name == "consoleLog",
+               let body = message.body as? [String: Any],
+               let level = body["level"] as? String,
+               let args = body["args"] as? [String] {
+                let text = args.joined(separator: " ")
+                print("[JS \(level.uppercased())] \(text)")
+            }
+        }
+
         func webView(
             _ webView: WKWebView,
             didFinish navigation: WKNavigation!