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]>
![github-advanced-security[bot]](https://avatars.githubusercontent.com/in/57789?s=60&v=4){kind=small}
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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]>
… 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]>
- 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]>
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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