Rewrites the Quickstart tutorial to provide a more focused, step-by-step
introduction to building MCP Apps. The guide now uses synced code fences
that pull from `examples/quickstart/`, ensuring all code shown in the
documentation is type-checked and tested.
Key improvements:
- Clearer project setup instructions with explicit commands
- Streamlined explanations of the tool + resource registration pattern
- Added screenshot showing the completed app
- E2E test coverage validates the example works end-to-end
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* feat(basic-host): add theme toggle and MCP style variables
Add theme support to basic-host example:
- theme.ts: Global theme manager with light/dark toggle
- host-styles.ts: Full set of MCP CSS variables using light-dark()
- ThemeToggle component with sun/moon icons
- Theme-aware CSS using CSS custom properties
- Pass theme + styles to apps via hostContext
- Notify apps when theme changes via sendHostContextChange
Apps now receive:
- hostContext.theme: 'light' | 'dark'
- hostContext.styles.variables: All 60+ MCP CSS variables
- onhostcontextchanged notifications when theme changes
* test: update e2e goldens for theme changes
* refactor(basic-host): use SDK types for ModelContext and AppMessage
- Import McpUiUpdateModelContextRequest and McpUiMessageRequest from SDK
- Replace custom ModelContext with McpUiUpdateModelContextRequest['params']
- Replace custom AppMessage with McpUiMessageRequest['params']
- Pass full message params instead of extracting text
- Format messages by extracting text from content blocks in display
* feat(basic-host): handle non-text content blocks in display
- Add formatContentBlock helper for text, image, audio, resource types
- Show placeholders like <image: image/png> for non-text content
- Apply to both messages and model context display
* test: update shadertoy screenshot
* test: update screenshots from CI (linux x64)
* feat: implement ui/notifications/tool-cancelled throughout SDK
Wire the tool-cancelled notification that hosts MUST send when tool
execution is cancelled (user action, timeout, classifier intervention, etc.):
- Add McpUiToolCancelledNotification type in spec.types.ts
- Generate Zod schema via ts-to-zod
- Add AppBridge.sendToolCancelled() method for hosts
- Add App.ontoolcancelled setter for guest UIs
- Export type and schema from types.ts
- Add tests for notification with/without reason
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* feat: add App.onteardown handler for graceful shutdown
Wire the guest UI side of ui/resource-teardown request:
- Add onteardown setter in App class for guest UIs to handle teardown
- Allow ui/resource-teardown in assertRequestHandlerCapability
- Import McpUiResourceTeardownRequest/Result types
- Add tests for sync and async cleanup handlers
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* feat(example): wire tool-cancelled and teardown in basic-host
Update basic-host example to properly use the new notifications:
- Send sendToolCancelled when tool call promise rejects
- Send sendResourceTeardown when React component unmounts
- Store appBridge ref for cleanup access
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* fix(example): implement graceful teardown per spec recommendation
Address review feedback: the host now waits for guest's teardown
response before unmounting, following the spec: "Host SHOULD wait
for a response before tearing down the resource (to prevent data loss)."
Changes:
- Add close button to tool call panels
- Two-phase unmount: isDestroying state dims panel and disables events
- sendResourceTeardown() completes before component removal
- Non-app tool results close immediately
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* feat(examples): add onteardown handlers to demo apps
Demonstrate graceful shutdown with simulated 500ms cleanup work.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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Co-authored-by: Claude <noreply@anthropic.com>
Extract server dropdown into ServerSelect component and simplify
ToolCallInfoPanel to read server name from toolCallInfo.serverInfo.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Add server selector to basic-host example
- Add ServerSelector component to switch between MCP servers
- Run all example servers concurrently on ports 3101-3107
- Update examples:start to launch all servers with assigned ports
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* Move server selector into tool call panel
- Server selector now in same component as tool selector
- Tool call results persist across server switches
- Connection caching avoids reconnects when switching servers
- Display server name with tool name in results (ServerName:ToolName)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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Co-authored-by: Claude <noreply@anthropic.com>
Change onsizechange handler to use min-width instead of width,
treating the app's reported size as a floor rather than exact.
Use min(Xpx, 100%) to allow shrinking with container.
Also remove outmost max-width constraint and simplify iframe CSS to
allow apps to demonstrate responsive growing.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Change marketing widget containers from fixed 600px to width: 100%
- Update basic-host iframe to use flex: 1 for proper expansion
- Widgets now fill their parent container instead of fixed size
Files changed:
- examples/budget-allocator-server/src/mcp-app.css
- examples/customer-segmentation-server/src/mcp-app.css
- examples/scenario-modeler-server/src/mcp-app.css
- examples/system-monitor-server/src/mcp-app.css
- examples/basic-host/src/index.module.css
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
Introduce new example implementations to replace simple-host and
simple-server:
- basic-host: Reference host implementation with double-iframe sandbox
pattern for secure UI isolation (outer iframe validates and relays
messages, inner iframe renders untrusted tool UI via srcdoc)
- basic-server-react: MCP server example demonstrating tool registration
with linked UI resources and React UI using the useApp() hook
Build infrastructure updates:
- Add build:all script and simplify CI/pre-commit to use it
- Add examples:dev for watch-mode development workflow
Also change PostMessageTransport logging from info to debug level.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
