fix: update Swift host example for new AppBridge API + fix multi-line doc comments

- Update McpHostViewModel callback signatures to match new AppBridge API:
  - onMessage now receives (role, content) instead of params object
  - onOpenLink now receives url string directly
  - onSizeChange now receives (width, height) directly
  - onLoggingMessage now receives (level, data, logger) directly
  - sendToolInput now takes arguments dictionary directly
  - sendToolResult now takes dictionary directly

- Fix Swift type generator to handle multi-line descriptions as proper doc comments
  instead of raw text that breaks compilation

🤖 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

@@ -398,38 +398,36 @@ class ToolCallInfo: ObservableObject, Identifiable {
         bridge.onInitialized = { [weak self] in
             Task { @MainActor in
                 guard let self = self else { return }
-                let params = McpUiToolInputParams(
-                    arguments: self.input.mapValues { AnyCodable($0) }
-                )
-                try? await bridge.sendToolInput(params)
+                let arguments = self.input.mapValues { AnyCodable($0) }
+                try? await bridge.sendToolInput(arguments: arguments)
                 if let result = self.result {
                     try? await self.sendToolResult(result, to: bridge)
                 }
             }
         }
 
-        bridge.onMessage = { params in
-            print("[Host] Message from Guest UI: \(params.role)")
+        bridge.onMessage = { role, content in
+            print("[Host] Message from Guest UI: \(role)")
             return McpUiMessageResult(isError: false)
         }
 
-        bridge.onOpenLink = { params in
-            print("[Host] Open link request: \(params.url)")
-            if let urlObj = URL(string: params.url) {
+        bridge.onOpenLink = { url in
+            print("[Host] Open link request: \(url)")
+            if let urlObj = URL(string: url) {
                 await MainActor.run {
                     UIApplication.shared.open(urlObj)
                 }
             }
             return McpUiOpenLinkResult(isError: false)
         }
 
-        bridge.onLoggingMessage = { params in
-            print("[Host] Guest UI log [\(params.level)]: \(params.data.value)")
+        bridge.onLoggingMessage = { level, data, logger in
+            print("[Host] Guest UI log [\(level)]: \(data.value)")
         }
 
-        bridge.onSizeChange = { [weak self] params in
-            print("[Host] Size change: \(params.width ?? 0) x \(params.height ?? 0)")
-            if let height = params.height {
+        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)
                 }
@@ -487,17 +485,20 @@ class ToolCallInfo: ObservableObject, Identifiable {
     }
 
     private func sendToolResult(_ result: ToolResult, to bridge: AppBridge) async throws {
-        let contentItems: [McpUiToolResultNotificationParamsContentItem] = result.content.compactMap { c in
+        let contentDicts: [[String: Any]] = result.content.compactMap { c in
             switch c {
             case .text(let text):
-                return .text(McpUiToolResultNotificationParamsContentItemText(type: "text", text: text))
+                return ["type": "text", "text": text]
             case .image(let data, let mimeType, _):
-                return .image(McpUiToolResultNotificationParamsContentItemImage(type: "image", data: data, mimeType: mimeType))
+                return ["type": "image", "data": data, "mimeType": mimeType]
             default:
                 return nil
             }
         }
-        let params = McpUiToolResultParams(content: contentItems, isError: result.isError)
+        let params: [String: AnyCodable] = [
+            "content": AnyCodable(contentDicts),
+            "isError": AnyCodable(result.isError ?? false)
+        ]
         try await bridge.sendToolResult(params)
     }
 

scripts/generate-swift-types.ts

@@ -369,7 +369,7 @@ function generateEnum(name: string, schema: JsonSchema): void {
       return `    case ${caseName} = "${value}"`;
     });
 
-  const desc = schema.description ? `/// ${schema.description}\n` : "";
+  const desc = formatSwiftDocComment(schema.description);
   typeDefinitions.push(`${desc}public enum ${canonical}: String, Codable, Sendable, Equatable {
 ${cases.join("\n")}
 }`);
@@ -419,7 +419,9 @@ function generateStruct(
 
   const propLines = properties
     .map((p) => {
-      const desc = p.description ? `    /// ${p.description}\n` : "";
+      const desc = p.description
+        ? p.description.split('\n').map(line => `    /// ${line}`).join('\n') + '\n'
+        : "";
       const typeDecl = p.isOptional ? `${p.type}?` : p.type;
       return `${desc}    public var ${p.swiftName}: ${typeDecl}`;
     })
@@ -453,7 +455,7 @@ ${keyLines}
     .map((p) => `        self.${p.swiftName} = ${p.swiftName}`)
     .join("\n");
 
-  const desc = schema.description ? `/// ${schema.description}\n` : "";
+  const desc = formatSwiftDocComment(schema.description);
   typeDefinitions.push(`${desc}public struct ${canonical}: Codable, Sendable, Equatable {
 ${propLines}${codingKeys}
 
@@ -469,6 +471,15 @@ function capitalize(s: string): string {
   return s.charAt(0).toUpperCase() + s.slice(1);
 }
 
+function formatSwiftDocComment(description: string | undefined): string {
+  if (!description) return "";
+  // Split into lines and prefix each with ///
+  return description
+    .split('\n')
+    .map(line => `/// ${line}`)
+    .join('\n') + '\n';
+}
+
 function generate(): string {
   const schema: SchemaDoc = JSON.parse(readFileSync(SCHEMA_FILE, "utf-8"));
   const defs = schema.$defs;