feat: Add Swift SDK for MCP Apps #132
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Swift SDK for hosting MCP Apps in iOS/macOS applications: SDK (swift/): - AppBridge: Host-side protocol handler - WKWebViewTransport: WebView communication - Generated types from schema.json - Full MCP Apps protocol support Example App (examples/basic-host-swift/): - SwiftUI app demonstrating SDK usage - Bottom toolbar UI (server/tool pickers) - WebView with AppBridge integration - Tool forwarding to MCP servers - Server name displayed in tool call cards Type Generator: - scripts/generate-swift-types.ts - Generates Swift types from JSON Schema CI: - Swift job on macos-latest - Builds and tests SDK 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
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Removed kotlin job from CI and kotlin paths from .prettierignore as they reference directories that don't exist. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
- Use EmptyCapability() instead of Bool for capabilities - Use McpUiToolInputNotificationParams instead of removed type - Use McpUiResourceMetaCsp for resource meta tests - Add @mainactor to WKWebViewTransport tests - Use actor-based state capture for Sendable closure compliance - Extract async values before XCTAssert calls 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
- Swift host: Add serverName to ToolCallInfo and display it in ToolCallCard header - JS host: Pass toolInfo with tool definition to hostContext when creating AppBridge 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
Call sendResourceTeardown() and close() on AppBridge before removing a tool call card, matching the recommended pattern from the web host. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
The previous implementation spawned a Task but removed the card immediately without waiting. Now properly awaits the teardown. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
Resolved conflict in examples/basic-host/src/index.tsx: - Keep toolCallInfo parameter for hostContext.toolInfo - Keep appBridgeRef.current assignment for teardown support 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
- Show spinner with "Closing..." text when tearing down - Dim card to 50% opacity during teardown - Hide close button while teardown is in progress 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
- Move isTearingDown to ToolCallInfo (observable state) - Remove local @State that caused desync issues - Add 5-second timeout to prevent stuck cards - Guard against double-tap with early return - Card observes model state via @ObservedObject 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
- Send params: [:] instead of nil (TS SDK expects object, not undefined) - Use strong reference for WebView in transport to prevent premature dealloc - Add guard for nil transport with proper error - Add debug logging to sendRequest 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
- Add toastMessage property and showToast() method to ViewModel - Add toast overlay at bottom of screen (auto-dismiss after 3s) - Change teardown() to return optional error message - Show toast when teardown fails or times out - Add OSLog-based logging for debugging - Improve logs.sh script for better log filtering 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
SDK changes: - Add timeout parameter to sendRequest (default 30s) - sendResourceTeardown uses 5s timeout - Add failPendingRequest helper for clean timeout handling Host changes: - Check isReady() before sending teardown - Skip teardown if bridge not yet initialized (no data to save) - Simplified logic since SDK handles timeout internally This prevents cards from getting stuck when closed before initialization. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
Changed from 5 seconds to 0.5 seconds for a snappier user experience. Added documentation comment explaining the timeout parameter. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
Updated McpHostViewModel to use the new typed params API: - onMessage, onOpenLink, onLoggingMessage, onSizeChange now take typed params - sendToolInput now takes McpUiToolInputParams - sendToolResult now takes McpUiToolResultParams with proper content items 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <[email protected]>
Replace hardcoded knownServers list with automatic server discovery: - Start from port 3101 and increment until connection times out (1 second) - Get server name from MCP initialization response (serverInfo.name) - Add Re-scan button to UI for manual re-discovery - Show 'Scanning...' progress indicator during discovery - Auto-connect to first discovered server Uses withThrowingTaskGroup for proper timeout handling with concurrent connect and sleep tasks.
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JSON integers are decoded as Int, not Double, but the code was casting to Double which failed silently. Use NSNumber to handle both Int and Double values from the JSON decoder.
…down 1. Size-changed notification now properly decodes to McpUiSizeChangedParams using JSONDecoder, with fallback to manual NSNumber extraction. 2. Teardown now always attempts to send the teardown request even if the app hasn't fully initialized (matching web host behavior). Previously it would skip teardown if isReady() returned false, causing the card to disappear immediately without giving the app a chance to clean up.
…sages Sync Swift SDK with ochafik/integ branch changes: - Add McpUiGuestNotification, McpUiGuestRequest, McpUiHostNotification, and McpUiHostRequest enums discriminated by 'method' field - Update AppBridge to decode incoming messages to typed enums - Update sending methods to use McpUiHostNotification enum - Add tests for enum encoding/decoding
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Summary
Swift low-level SDK (AppBridge) for hosting MCP Apps in iOS/macOS applications, and basic example iOS app.
To test, ensure you have XCode + an iOS Simulator & run:
Similar work for Kotlin / Android: #134
What's included
SDK (
swift/)scripts/generate-swift-types.tsExample App (
examples/basic-host-swift/)example/basic-host)CI
How to test
cd examples/basic-host-swift ./scripts/run.shScreenshots
The example app displays MCP App UIs in a WebView with full protocol support.
🤖 Generated with Claude Code