feat(basic-host): URL params, fullscreen mode, unified layout (#266)

* basic-host: handle containerDimensions

* feat(basic-host): Unified tool call layout with shared collapsible panels

* snapshots

* format

Author: ochafik

examples/basic-host/src/implementation.ts

@@ -228,12 +228,19 @@ export type AppMessage = McpUiMessageRequest["params"];
 export interface AppBridgeCallbacks {
   onContextUpdate?: (context: ModelContext | null) => void;
   onMessage?: (message: AppMessage) => void;
+  onDisplayModeChange?: (mode: "inline" | "fullscreen") => void;
+}
+
+export interface AppBridgeOptions {
+  containerDimensions?: { maxHeight?: number; width?: number } | { height: number; width?: number };
+  displayMode?: "inline" | "fullscreen";
 }
 
 export function newAppBridge(
   serverInfo: ServerInfo,
   iframe: HTMLIFrameElement,
   callbacks?: AppBridgeCallbacks,
+  options?: AppBridgeOptions,
 ): AppBridge {
   const serverCapabilities = serverInfo.client.getServerCapabilities();
   const appBridge = new AppBridge(serverInfo.client, IMPLEMENTATION, {
@@ -242,6 +249,12 @@ export function newAppBridge(
     serverResources: serverCapabilities?.resources,
     // Declare support for model context updates
     updateModelContext: { text: {} },
+  }, {
+    hostContext: {
+      containerDimensions: options?.containerDimensions ?? { maxHeight: 600 },
+      displayMode: options?.displayMode ?? "inline",
+      availableDisplayModes: ["inline", "fullscreen"],
+    },
   });
 
   // Register all handlers before calling connect(). The Guest UI can start
@@ -308,5 +321,18 @@ export function newAppBridge(
     iframe.animate([from, to], { duration: 300, easing: "ease-out" });
   };
 
+  // Handle display mode change requests from the app
+  appBridge.onrequestdisplaymode = async (params) => {
+    log.info("Display mode request from MCP App:", params);
+    const newMode = params.mode === "fullscreen" ? "fullscreen" : "inline";
+    // Update host context and notify the app
+    appBridge.sendHostContextChange({
+      displayMode: newMode,
+    });
+    // Notify the host UI (via callback)
+    callbacks?.onDisplayModeChange?.(newMode);
+    return { mode: newMode };
+  };
+
   return appBridge;
 }

examples/basic-host/src/index.module.css

@@ -72,65 +72,15 @@
 
 .toolCallInfoPanel {
   display: flex;
-  gap: 1rem;
+  flex-direction: column;
+  gap: 0.5rem;
   animation: slideDown 0.3s ease-out;
 }
 
 @keyframes slideDown {
   from { opacity: 0; transform: translateY(-12px); }
 }
 
-.inputInfoPanel {
-  display: flex;
-  flex: 3;
-  flex-direction: column;
-  gap: 0.5rem;
-  min-width: 0;
-
-  h2 {
-    display: flex;
-    flex-direction: column;
-    margin: 0;
-    font-size: 1.5rem;
-    position: relative;
-
-    .toolName {
-      font-family: monospace;
-    }
-
-    .closeButton {
-      position: absolute;
-      top: 0;
-      right: 0;
-      width: 1.5rem;
-      height: 1.5rem;
-      padding: 0;
-      border: none;
-      border-radius: 4px;
-      background: #e0e0e0;
-      font-size: 1.25rem;
-      line-height: 1;
-      color: #666;
-      cursor: pointer;
-
-      &:hover {
-        background: #d0d0d0;
-        color: #333;
-      }
-    }
-  }
-}
-
-.outputInfoPanel {
-  flex: 4;
-  min-width: 0;
-}
-
-.appOutputPanel {
-  flex: 1;
-  min-width: 0;
-}
-
 .appHeader {
   display: flex;
   align-items: center;
@@ -166,16 +116,6 @@
   }
 }
 
-.jsonBlock {
-  flex-grow: 1;
-  min-height: 0;
-  margin: 0;
-  padding: 1rem;
-  border-radius: 4px;
-  background-color: #f5f5f5;
-  overflow: auto;
-}
-
 .appIframePanel {
   min-height: 200px;
 
@@ -186,6 +126,62 @@
     border: 3px dashed #888;
     border-radius: 4px;
   }
+
+  &.fullscreen {
+    position: fixed;
+    top: 0;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    z-index: 1000;
+    margin: 0;
+    padding: 1rem;
+    max-width: none;
+    background: white;
+    border: none;
+    border-radius: 0;
+    display: flex;
+    flex-direction: column;
+
+    /* Hide collapsible panels in fullscreen */
+    .collapsiblePanel {
+      display: none;
+    }
+
+    iframe {
+      flex: 1;
+      height: 100%;
+      border: none;
+      border-radius: 0;
+    }
+  }
+}
+
+.appToolbar {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  margin-bottom: 0.5rem;
+
+  .collapsiblePanel {
+    flex: 1;
+    margin: 0;
+  }
+}
+
+.fullscreenButton {
+  width: 32px;
+  height: 32px;
+  padding: 0;
+  border: 1px solid #ccc;
+  border-radius: 4px;
+  background: #f5f5f5;
+  font-size: 1.25rem;
+  cursor: pointer;
+
+  &:hover {
+    background: #e0e0e0;
+  }
 }
 
 .collapsiblePanel {