diff --git a/biome.json b/biome.json
index 9f2044a..a1804f6 100644
--- a/biome.json
+++ b/biome.json
@@ -38,7 +38,8 @@
         "noSvgWithoutTitle": "off",
         "useButtonType": "off",
         "useFocusableInteractive": "off",
-        "useKeyWithClickEvents": "off"
+        "useKeyWithClickEvents": "off",
+        "noAutofocus": "off"
       },
       "suspicious": {
         "noArrayIndexKey": "off",
diff --git a/registry.json b/registry.json
index 0c939c8..0adac32 100644
--- a/registry.json
+++ b/registry.json
@@ -345,7 +345,8 @@
         "@nteract/isolated-frame",
         "@nteract/widget-store",
         "@nteract/markdown-output",
-        "@nteract/error-boundary"
+        "@nteract/error-boundary",
+        "@nteract/highlight-text"
       ],
       "files": [
         {
@@ -948,6 +949,19 @@
         }
       ]
     },
+    {
+      "name": "highlight-text",
+      "type": "registry:lib",
+      "title": "Highlight Text",
+      "description": "DOM utility for highlighting search matches in text content with customizable styling.",
+      "files": [
+        {
+          "path": "registry/lib/highlight-text.ts",
+          "type": "registry:lib",
+          "target": "lib/highlight-text.ts"
+        }
+      ]
+    },
     {
       "name": "isolated-renderer",
       "type": "registry:component",
diff --git a/registry/cell/CellContainer.tsx b/registry/cell/CellContainer.tsx
index d55e144..d453bc8 100644
--- a/registry/cell/CellContainer.tsx
+++ b/registry/cell/CellContainer.tsx
@@ -94,7 +94,7 @@ export const CellContainer = forwardRef<HTMLDivElement, CellContainerProps>(
                   ribbonColor,
                 )}
               />
-              <div className="min-w-0 flex-1 py-3 pl-5 pr-3">{codeContent}</div>
+              <div className="min-w-0 flex-1 py-3 pl-6 pr-3">{codeContent}</div>
             </div>
             {/* Output row - ribbon + content together */}
             {hasOutput && (
@@ -107,7 +107,7 @@ export const CellContainer = forwardRef<HTMLDivElement, CellContainerProps>(
                 />
                 <div
                   className={cn(
-                    "min-w-0 flex-1 py-2 pl-5 pr-3 transition-opacity duration-150",
+                    "min-w-0 flex-1 py-2 pl-6 pr-3 transition-opacity duration-150",
                     !isFocused && "opacity-70",
                   )}
                 >
@@ -125,7 +125,7 @@ export const CellContainer = forwardRef<HTMLDivElement, CellContainerProps>(
                 ribbonColor,
               )}
             />
-            <div className="min-w-0 flex-1 py-3 pl-5 pr-3">{children}</div>
+            <div className="min-w-0 flex-1 py-3 pl-6 pr-3">{children}</div>
           </div>
         )}
         {/* Right margin - pt-3 aligns with left gutter, appears on hover/focus */}
diff --git a/registry/cell/CellTypeSelector.tsx b/registry/cell/CellTypeSelector.tsx
index 6301305..88fb923 100644
--- a/registry/cell/CellTypeSelector.tsx
+++ b/registry/cell/CellTypeSelector.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 import { Bot, ChevronDown, Code, Database, FileText } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import {
diff --git a/registry/cell/CollaboratorAvatars.tsx b/registry/cell/CollaboratorAvatars.tsx
index 54de622..6914c0a 100644
--- a/registry/cell/CollaboratorAvatars.tsx
+++ b/registry/cell/CollaboratorAvatars.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 import * as React from "react";
 import {
   Avatar,
diff --git a/registry/cell/CompactExecutionButton.tsx b/registry/cell/CompactExecutionButton.tsx
index 3d5071f..0339c89 100644
--- a/registry/cell/CompactExecutionButton.tsx
+++ b/registry/cell/CompactExecutionButton.tsx
@@ -38,7 +38,6 @@ export function CompactExecutionButton({
   return (
     <button
       type="button"
-      data-testid="execute-button"
       onClick={handleClick}
       className={cn(
         "group/exec inline-flex items-center font-mono text-sm tabular-nums",
@@ -47,6 +46,7 @@ export function CompactExecutionButton({
         className,
       )}
       title={isExecuting ? "Stop execution" : "Run cell"}
+      data-testid="execute-button"
     >
       <span className="opacity-60">[</span>
       <span className="relative inline-flex min-w-4 items-center justify-center">
diff --git a/registry/cell/OutputArea.tsx b/registry/cell/OutputArea.tsx
index c6a857b..fe706b5 100644
--- a/registry/cell/OutputArea.tsx
+++ b/registry/cell/OutputArea.tsx
@@ -12,6 +12,7 @@ import {
 import { isDarkMode as detectDarkMode } from "@/lib/dark-mode";
 import { cn } from "@/lib/utils";
 import { ErrorBoundary } from "@/registry/lib/error-boundary";
+import { highlightTextInDom } from "@/registry/lib/highlight-text";
 import { OutputErrorFallback } from "@/registry/lib/output-error-fallback";
 import {
   AnsiErrorOutput,
@@ -107,6 +108,16 @@ interface OutputAreaProps {
    * @deprecated Use the comm bridge instead for full widget support
    */
   onWidgetUpdate?: (commId: string, state: Record<string, unknown>) => void;
+  /**
+   * Search query to highlight in iframe outputs.
+   * Empty string or undefined clears highlights.
+   */
+  searchQuery?: string;
+  /**
+   * Callback reporting how many search matches were found in this cell's outputs.
+   * Called when iframe reports search_results or in-DOM highlighting completes.
+   */
+  onSearchMatchCount?: (count: number) => void;
 }
 
 /**
@@ -279,10 +290,15 @@ export function OutputArea({
   preloadIframe = false,
   onLinkClick,
   onWidgetUpdate,
+  searchQuery,
+  onSearchMatchCount,
 }: OutputAreaProps) {
   const id = useId();
   const frameRef = useRef<IsolatedFrameHandle>(null);
   const bridgeRef = useRef<CommBridgeManager | null>(null);
+  const inDomOutputRef = useRef<HTMLDivElement>(null);
+  const searchQueryRef = useRef(searchQuery);
+  searchQueryRef.current = searchQuery;
 
   // Track dark mode state and observe changes
   const [darkMode, setDarkMode] = useState(() => detectDarkMode());
@@ -319,7 +335,6 @@ export function OutputArea({
   const shouldUseBridge = shouldIsolate && hasWidgets && widgetContext !== null;
 
   const hasCollapseControl = onToggleCollapse !== undefined;
-  const outputCount = outputs.length;
 
   // Handle messages from iframe, routing widget messages to comm bridge
   const handleIframeMessage = useCallback(
@@ -333,8 +348,13 @@ export function OutputArea({
       if (message.type === "widget_update" && onWidgetUpdate) {
         onWidgetUpdate(message.payload.commId, message.payload.state);
       }
+
+      // Capture search result count from iframe
+      if (message.type === "search_results") {
+        onSearchMatchCount?.(message.payload.count);
+      }
     },
-    [onWidgetUpdate],
+    [onWidgetUpdate, onSearchMatchCount],
   );
 
   // Callback when frame is ready - set up bridge and render outputs
@@ -399,6 +419,11 @@ export function OutputArea({
         });
       }
     });
+
+    // Re-apply search highlights after rendering new content
+    if (searchQueryRef.current) {
+      frameRef.current?.search(searchQueryRef.current);
+    }
   }, [outputs, priority, shouldUseBridge, widgetContext]);
 
   // Clean up bridge on unmount
@@ -418,6 +443,29 @@ export function OutputArea({
     }
   }, [handleFrameReady]);
 
+  // Forward search query to the iframe (for isolated outputs)
+  useEffect(() => {
+    if (frameRef.current?.isIframeReady) {
+      frameRef.current.search(searchQuery || "");
+    }
+  }, [searchQuery]);
+
+  // Highlight search matches in in-DOM outputs
+  // Re-run when outputs array ref changes so new content gets highlighted
+  useEffect(() => {
+    if (shouldIsolate) return; // iframe reports its own count via search_results
+    if (!searchQuery || !inDomOutputRef.current || outputs.length === 0) {
+      // Only report 0 if we were previously tracking matches for this cell
+      if (searchQuery) onSearchMatchCount?.(0);
+      return;
+    }
+    const cleanup = highlightTextInDom(inDomOutputRef.current, searchQuery);
+    const count =
+      inDomOutputRef.current.querySelectorAll(".global-find-match").length;
+    onSearchMatchCount?.(count);
+    return cleanup;
+  }, [searchQuery, shouldIsolate, outputs, onSearchMatchCount]);
+
   // Empty state: render nothing (unless preloading iframe)
   if (outputs.length === 0 && !showPreloadedIframe) {
     return null;
@@ -447,7 +495,7 @@ export function OutputArea({
           )}
           <span>
             {collapsed
-              ? `Show ${outputCount} output${outputCount > 1 ? "s" : ""}`
+              ? `Show ${outputs.length} output${outputs.length > 1 ? "s" : ""}`
               : "Hide outputs"}
           </span>
         </button>
@@ -480,34 +528,37 @@ export function OutputArea({
           )}
 
           {/* In-DOM outputs (when not using isolation) */}
-          {!shouldIsolate &&
-            outputs.map((output, index) => (
-              <div
-                key={`output-${index}`}
-                data-slot="output-item"
-                data-output-index={index}
-              >
-                <ErrorBoundary
-                  resetKeys={[JSON.stringify(output)]}
-                  fallback={(error, reset) => (
-                    <OutputErrorFallback
-                      error={error}
-                      outputIndex={index}
-                      onRetry={reset}
-                    />
-                  )}
-                  onError={(error, errorInfo) => {
-                    console.error(
-                      `[OutputArea] Error rendering output ${index}:`,
-                      error,
-                      errorInfo.componentStack,
-                    );
-                  }}
+          {!shouldIsolate && (
+            <div ref={inDomOutputRef}>
+              {outputs.map((output, index) => (
+                <div
+                  key={`output-${index}`}
+                  data-slot="output-item"
+                  data-output-index={index}
                 >
-                  {renderOutput(output, index, renderers, priority)}
-                </ErrorBoundary>
-              </div>
-            ))}
+                  <ErrorBoundary
+                    resetKeys={[JSON.stringify(output)]}
+                    fallback={(error, reset) => (
+                      <OutputErrorFallback
+                        error={error}
+                        outputIndex={index}
+                        onRetry={reset}
+                      />
+                    )}
+                    onError={(error, errorInfo) => {
+                      console.error(
+                        `[OutputArea] Error rendering output ${index}:`,
+                        error,
+                        errorInfo.componentStack,
+                      );
+                    }}
+                  >
+                    {renderOutput(output, index, renderers, priority)}
+                  </ErrorBoundary>
+                </div>
+              ))}
+            </div>
+          )}
         </div>
       )}
     </div>
diff --git a/registry/cell/PresenceBookmarks.tsx b/registry/cell/PresenceBookmarks.tsx
index 7c6a907..1aa0366 100644
--- a/registry/cell/PresenceBookmarks.tsx
+++ b/registry/cell/PresenceBookmarks.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 import type * as React from "react";
 import { Avatar, AvatarFallback, AvatarImage } from "@/components/ui/avatar";
 import {
diff --git a/registry/editor/extensions.ts b/registry/editor/extensions.ts
index 86b8059..2f251cf 100644
--- a/registry/editor/extensions.ts
+++ b/registry/editor/extensions.ts
@@ -34,6 +34,11 @@ export const notebookEditorTheme = EditorView.theme({
   "&.cm-focused": {
     outline: "none",
   },
+  // Reset line padding so code aligns with output areas
+  // (CodeMirror's base theme adds "padding: 0 2px 0 6px" to .cm-line)
+  ".cm-line": {
+    paddingLeft: "0",
+  },
   // Mobile-friendly padding
   "@media (max-width: 640px)": {
     ".cm-content": {
diff --git a/registry/lib/highlight-text.ts b/registry/lib/highlight-text.ts
new file mode 100644
index 0000000..870747c
--- /dev/null
+++ b/registry/lib/highlight-text.ts
@@ -0,0 +1,66 @@
+/**
+ * Highlight all occurrences of a search query within a DOM container.
+ *
+ * Walks text nodes using TreeWalker, wraps matches in <mark> elements.
+ * Returns a cleanup function that removes all marks and restores text nodes.
+ */
+export function highlightTextInDom(
+  container: HTMLElement,
+  query: string,
+): () => void {
+  if (!query) return () => {};
+
+  const marks: HTMLElement[] = [];
+  const walker = document.createTreeWalker(
+    container,
+    NodeFilter.SHOW_TEXT,
+    null,
+  );
+  const lowerQuery = query.toLowerCase();
+
+  // Collect matches first (to avoid mutating DOM while walking)
+  const matches: { node: Text; offset: number; length: number }[] = [];
+  let node = walker.nextNode();
+  while (node) {
+    const text = node.nodeValue || "";
+    const lowerText = text.toLowerCase();
+    let pos = lowerText.indexOf(lowerQuery, 0);
+    while (pos !== -1) {
+      matches.push({ node: node as Text, offset: pos, length: query.length });
+      pos = lowerText.indexOf(lowerQuery, pos + query.length);
+    }
+    node = walker.nextNode();
+  }
+
+  // Apply highlights in reverse order to preserve offsets
+  for (let i = matches.length - 1; i >= 0; i--) {
+    const m = matches[i];
+    try {
+      const range = document.createRange();
+      range.setStart(m.node, m.offset);
+      range.setEnd(m.node, m.offset + m.length);
+      const mark = document.createElement("mark");
+      mark.className = "global-find-match";
+      mark.style.cssText =
+        "background: #fbbf24; color: #000; border-radius: 2px; padding: 0;";
+      range.surroundContents(mark);
+      marks.unshift(mark);
+    } catch {
+      // surroundContents can fail if range crosses element boundaries
+    }
+  }
+
+  // Return cleanup function
+  return () => {
+    for (const mark of marks) {
+      const parent = mark.parentNode;
+      if (parent) {
+        while (mark.firstChild) {
+          parent.insertBefore(mark.firstChild, mark);
+        }
+        parent.removeChild(mark);
+        parent.normalize();
+      }
+    }
+  };
+}
diff --git a/registry/lib/widget-error-fallback.tsx b/registry/lib/widget-error-fallback.tsx
index 7c4464c..ee7efe6 100644
--- a/registry/lib/widget-error-fallback.tsx
+++ b/registry/lib/widget-error-fallback.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 import { cn } from "@/lib/utils";
 
 export interface WidgetErrorFallbackProps {
diff --git a/registry/outputs/isolated/__tests__/comm-bridge-manager.test.ts b/registry/outputs/isolated/__tests__/comm-bridge-manager.test.ts
index 992e092..1e645bb 100644
--- a/registry/outputs/isolated/__tests__/comm-bridge-manager.test.ts
+++ b/registry/outputs/isolated/__tests__/comm-bridge-manager.test.ts
@@ -90,6 +90,8 @@ function createMockFrame(): {
     eval: vi.fn(),
     setTheme: vi.fn(),
     clear: vi.fn(),
+    search: vi.fn(),
+    searchNavigate: vi.fn(),
     isReady: true,
     isIframeReady: true,
   };
diff --git a/registry/outputs/isolated/comm-bridge-manager.ts b/registry/outputs/isolated/comm-bridge-manager.ts
index efb5332..45d534a 100644
--- a/registry/outputs/isolated/comm-bridge-manager.ts
+++ b/registry/outputs/isolated/comm-bridge-manager.ts
@@ -370,9 +370,11 @@ export class CommBridgeManager {
 
     const unsubscribe = this.store.subscribeToCustomMessage(
       commId,
-      (content, buffers) => {
+      (content: Record<string, unknown>, buffers?: DataView[]) => {
         // Convert DataView[] to ArrayBuffer[] for postMessage
-        const arrayBuffers = buffers?.map((dv) => dv.buffer as ArrayBuffer);
+        const arrayBuffers = buffers?.map(
+          (dv: DataView) => dv.buffer as ArrayBuffer,
+        );
         // Forward custom message to iframe
         this.sendCommMsg(commId, "custom", content, arrayBuffers);
       },
diff --git a/registry/outputs/isolated/frame-bridge.ts b/registry/outputs/isolated/frame-bridge.ts
index 5952489..3cfa119 100644
--- a/registry/outputs/isolated/frame-bridge.ts
+++ b/registry/outputs/isolated/frame-bridge.ts
@@ -168,6 +168,33 @@ export interface BridgeReadyMessage {
   type: "bridge_ready";
 }
 
+// --- Global Find: Parent → Iframe ---
+
+/**
+ * Search for text within the iframe's rendered content.
+ * The iframe should highlight all matches and report the count.
+ */
+export interface SearchMessage {
+  type: "search";
+  payload: {
+    /** The search query string (empty string clears search) */
+    query: string;
+    /** Whether the search should be case-sensitive */
+    caseSensitive?: boolean;
+  };
+}
+
+/**
+ * Navigate to a specific match in the iframe's search results.
+ */
+export interface SearchNavigateMessage {
+  type: "search_navigate";
+  payload: {
+    /** The index of the match to navigate to (0-based) */
+    matchIndex: number;
+  };
+}
+
 /**
  * All message types that can be sent from parent to iframe.
  */
@@ -182,7 +209,9 @@ export type ParentToIframeMessage =
   | CommMsgMessage
   | CommCloseMessage
   | CommSyncMessage
-  | BridgeReadyMessage;
+  | BridgeReadyMessage
+  | SearchMessage
+  | SearchNavigateMessage;
 
 // --- Message Types: Iframe → Parent ---
 
@@ -337,6 +366,20 @@ export interface WidgetCommCloseMessage {
   };
 }
 
+// --- Global Find: Iframe → Parent ---
+
+/**
+ * Report search results from the iframe.
+ * Sent after processing a search message.
+ */
+export interface SearchResultsMessage {
+  type: "search_results";
+  payload: {
+    /** Number of matches found */
+    count: number;
+  };
+}
+
 /**
  * All message types that can be sent from iframe to parent.
  */
@@ -353,7 +396,8 @@ export type IframeToParentMessage =
   | RendererReadyMessage
   | WidgetReadyMessage
   | WidgetCommMsgMessage
-  | WidgetCommCloseMessage;
+  | WidgetCommCloseMessage
+  | SearchResultsMessage;
 
 // --- Utility Types ---
 
@@ -389,6 +433,7 @@ export function isIframeMessage(data: unknown): data is IframeToParentMessage {
       "widget_ready",
       "widget_comm_msg",
       "widget_comm_close",
+      "search_results",
     ].includes(msg.type)
   );
 }
diff --git a/registry/outputs/isolated/frame-html.ts b/registry/outputs/isolated/frame-html.ts
index 50cb1a6..4e9aa8d 100644
--- a/registry/outputs/isolated/frame-html.ts
+++ b/registry/outputs/isolated/frame-html.ts
@@ -69,16 +69,11 @@ export function generateFrameHtml(options: FrameHtmlOptions = {}): string {
       margin: 0;
       padding: 0;
       font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
-      font-size: 14px;
       line-height: 1.5;
       background: transparent;
       color: var(--text-primary);
     }
 
-    body {
-      padding: 8px;
-    }
-
     /* Output container */
     #root {
       min-height: 1px;
@@ -200,6 +195,14 @@ export function generateFrameHtml(options: FrameHtmlOptions = {}): string {
               handleWidgetState(payload);
               break;
 
+            case 'search':
+              handleSearch(payload);
+              break;
+
+            case 'search_navigate':
+              handleSearchNavigate(payload);
+              break;
+
             // Comm bridge messages - handled by React widget system, ignore here
             case 'bridge_ready':
             case 'comm_open':
@@ -393,6 +396,85 @@ export function generateFrameHtml(options: FrameHtmlOptions = {}): string {
         window.dispatchEvent(new CustomEvent('widget_state', { detail: payload }));
       }
 
+      // --- Search ---
+      var searchMarks = [];
+      var currentSearchIndex = -1;
+
+      function handleSearch(payload) {
+        var query = (payload && payload.query) || '';
+        var caseSensitive = payload && payload.caseSensitive;
+        clearSearchMarks();
+        if (!query) {
+          send('search_results', { count: 0 });
+          return;
+        }
+        var marks = [];
+        var walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT, null);
+        var node;
+        var compareQuery = caseSensitive ? query : query.toLowerCase();
+        // Collect all text nodes and their match positions
+        var matches = [];
+        while ((node = walker.nextNode())) {
+          var text = node.nodeValue || '';
+          var compareText = caseSensitive ? text : text.toLowerCase();
+          var pos = 0;
+          while ((pos = compareText.indexOf(compareQuery, pos)) !== -1) {
+            matches.push({ node: node, offset: pos, length: query.length });
+            pos += query.length;
+          }
+        }
+        // Highlight matches in reverse order to preserve offsets
+        for (var i = matches.length - 1; i >= 0; i--) {
+          var m = matches[i];
+          try {
+            var range = document.createRange();
+            range.setStart(m.node, m.offset);
+            range.setEnd(m.node, m.offset + m.length);
+            var mark = document.createElement('mark');
+            mark.className = 'global-find-match';
+            mark.style.cssText = 'background: #fbbf24; color: #000; border-radius: 2px; padding: 0;';
+            range.surroundContents(mark);
+            marks.unshift(mark);
+          } catch (e) {
+            // surroundContents can fail if range crosses element boundaries
+          }
+        }
+        searchMarks = marks;
+        currentSearchIndex = -1;
+        send('search_results', { count: marks.length });
+      }
+
+      function handleSearchNavigate(payload) {
+        var matchIndex = (payload && payload.matchIndex) || 0;
+        if (searchMarks.length === 0) return;
+        // Clear previous active highlight
+        if (currentSearchIndex >= 0 && currentSearchIndex < searchMarks.length) {
+          searchMarks[currentSearchIndex].style.cssText = 'background: #fbbf24; color: #000; border-radius: 2px; padding: 0;';
+        }
+        currentSearchIndex = matchIndex;
+        if (currentSearchIndex >= 0 && currentSearchIndex < searchMarks.length) {
+          var active = searchMarks[currentSearchIndex];
+          active.style.cssText = 'background: #f97316; color: #000; border-radius: 2px; padding: 0;';
+          active.scrollIntoView({ block: 'nearest', behavior: 'smooth' });
+        }
+      }
+
+      function clearSearchMarks() {
+        for (var i = 0; i < searchMarks.length; i++) {
+          var mark = searchMarks[i];
+          var parent = mark.parentNode;
+          if (parent) {
+            while (mark.firstChild) {
+              parent.insertBefore(mark.firstChild, mark);
+            }
+            parent.removeChild(mark);
+            parent.normalize();
+          }
+        }
+        searchMarks = [];
+        currentSearchIndex = -1;
+      }
+
       // --- Utilities ---
 
       function send(type, payload) {
diff --git a/registry/outputs/isolated/index.ts b/registry/outputs/isolated/index.ts
index 495db33..8f3e9b8 100644
--- a/registry/outputs/isolated/index.ts
+++ b/registry/outputs/isolated/index.ts
@@ -1,6 +1,3 @@
-// Production components
-
-// Widget comm bridge for isolated frames
 export {
   CommBridgeManager,
   createCommBridgeManager,
diff --git a/registry/outputs/isolated/isolated-frame.tsx b/registry/outputs/isolated/isolated-frame.tsx
index 2caf17b..54b669e 100644
--- a/registry/outputs/isolated/isolated-frame.tsx
+++ b/registry/outputs/isolated/isolated-frame.tsx
@@ -112,6 +112,17 @@ export interface IsolatedFrameHandle {
    */
   clear: () => void;
 
+  /**
+   * Search for text within the iframe's rendered content.
+   * Pass empty string to clear search highlights.
+   */
+  search: (query: string, caseSensitive?: boolean) => void;
+
+  /**
+   * Navigate to a specific search match by index.
+   */
+  searchNavigate: (matchIndex: number) => void;
+
   /**
    * Whether the iframe is ready to receive messages.
    * True after the React renderer bundle is initialized.
@@ -431,6 +442,24 @@ export const IsolatedFrame = forwardRef<
       setTheme: (isDark: boolean) =>
         send({ type: "theme", payload: { isDark } }),
       clear: () => send({ type: "clear" }),
+      search: (query: string, caseSensitive?: boolean) => {
+        // Search handler is in bootstrap HTML, so send directly when iframe is loaded
+        // (bypasses the isReady queue which waits for the React renderer)
+        if (iframeRef.current?.contentWindow) {
+          iframeRef.current.contentWindow.postMessage(
+            { type: "search", payload: { query, caseSensitive } },
+            "*",
+          );
+        }
+      },
+      searchNavigate: (matchIndex: number) => {
+        if (iframeRef.current?.contentWindow) {
+          iframeRef.current.contentWindow.postMessage(
+            { type: "search_navigate", payload: { matchIndex } },
+            "*",
+          );
+        }
+      },
       isReady,
       isIframeReady,
     }),
diff --git a/registry/outputs/media-router.tsx b/registry/outputs/media-router.tsx
index 6d309a6..c9da0a6 100644
--- a/registry/outputs/media-router.tsx
+++ b/registry/outputs/media-router.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 import { lazy, type ReactNode, Suspense } from "react";
 import { useMediaContext } from "./media-provider";
 
@@ -346,6 +344,19 @@ export function MediaRouter({
       return <AnsiOutput className={className}>{String(content)}</AnsiOutput>;
     }
 
+    // Widget view JSON - when rendered in-DOM without a widget renderer,
+    // show a helpful message instead of raw JSON. This typically happens
+    // when a widget is displayed inside an Output widget.
+    if (mimeType === "application/vnd.jupyter.widget-view+json") {
+      return (
+        <div className="py-2 px-3 text-sm text-muted-foreground bg-muted/50 rounded border border-border">
+          <span className="font-medium">Nested widget</span>
+          <span className="mx-1">·</span>
+          <span>Widgets inside Output widgets are not yet supported</span>
+        </div>
+      );
+    }
+
     // Unknown +json types without custom renderer - show as JSON
     if (mimeType.includes("+json")) {
       return (
diff --git a/registry/widgets/controls/accordion-widget.tsx b/registry/widgets/controls/accordion-widget.tsx
index 6f71125..ea5dd9e 100644
--- a/registry/widgets/controls/accordion-widget.tsx
+++ b/registry/widgets/controls/accordion-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Accordion widget - collapsible panel container.
  *
diff --git a/registry/widgets/controls/audio-widget.tsx b/registry/widgets/controls/audio-widget.tsx
index e5a8ad4..6bf2265 100644
--- a/registry/widgets/controls/audio-widget.tsx
+++ b/registry/widgets/controls/audio-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Audio widget - plays audio from the kernel.
  *
diff --git a/registry/widgets/controls/box-widget.tsx b/registry/widgets/controls/box-widget.tsx
index 7de0aab..42ac3dd 100644
--- a/registry/widgets/controls/box-widget.tsx
+++ b/registry/widgets/controls/box-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Box widget - generic flex container.
  *
diff --git a/registry/widgets/controls/button-widget.tsx b/registry/widgets/controls/button-widget.tsx
index 1f9832e..fadf225 100644
--- a/registry/widgets/controls/button-widget.tsx
+++ b/registry/widgets/controls/button-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Button widget - renders a clickable button.
  *
diff --git a/registry/widgets/controls/checkbox-widget.tsx b/registry/widgets/controls/checkbox-widget.tsx
index 61dcdd3..9beadf6 100644
--- a/registry/widgets/controls/checkbox-widget.tsx
+++ b/registry/widgets/controls/checkbox-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Checkbox widget - renders a checkbox input.
  *
diff --git a/registry/widgets/controls/color-picker.tsx b/registry/widgets/controls/color-picker.tsx
index 4f00606..b543c03 100644
--- a/registry/widgets/controls/color-picker.tsx
+++ b/registry/widgets/controls/color-picker.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * ColorPicker widget - renders a color selection input.
  *
diff --git a/registry/widgets/controls/controller-axis-widget.tsx b/registry/widgets/controls/controller-axis-widget.tsx
index a085465..ba219b0 100644
--- a/registry/widgets/controls/controller-axis-widget.tsx
+++ b/registry/widgets/controls/controller-axis-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * ControllerAxis widget - displays a gamepad axis value.
  *
diff --git a/registry/widgets/controls/controller-button-widget.tsx b/registry/widgets/controls/controller-button-widget.tsx
index a2c95b7..e664a81 100644
--- a/registry/widgets/controls/controller-button-widget.tsx
+++ b/registry/widgets/controls/controller-button-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * ControllerButton widget - displays a gamepad button state.
  *
diff --git a/registry/widgets/controls/dropdown-widget.tsx b/registry/widgets/controls/dropdown-widget.tsx
index e788363..788d364 100644
--- a/registry/widgets/controls/dropdown-widget.tsx
+++ b/registry/widgets/controls/dropdown-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Dropdown widget - renders a native select dropdown.
  *
diff --git a/registry/widgets/controls/float-log-slider.tsx b/registry/widgets/controls/float-log-slider.tsx
index 2e88492..08d617c 100644
--- a/registry/widgets/controls/float-log-slider.tsx
+++ b/registry/widgets/controls/float-log-slider.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * FloatLogSlider widget - renders a logarithmic scale slider.
  *
diff --git a/registry/widgets/controls/float-progress.tsx b/registry/widgets/controls/float-progress.tsx
index ce1d681..6a4b8c3 100644
--- a/registry/widgets/controls/float-progress.tsx
+++ b/registry/widgets/controls/float-progress.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * FloatProgress widget - renders a floating point progress bar.
  *
diff --git a/registry/widgets/controls/float-range-slider.tsx b/registry/widgets/controls/float-range-slider.tsx
index 7ab5456..ecdda79 100644
--- a/registry/widgets/controls/float-range-slider.tsx
+++ b/registry/widgets/controls/float-range-slider.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * FloatRangeSlider widget - renders a dual-handle range slider for floats.
  *
diff --git a/registry/widgets/controls/float-slider.tsx b/registry/widgets/controls/float-slider.tsx
index 0d89356..5a3de2b 100644
--- a/registry/widgets/controls/float-slider.tsx
+++ b/registry/widgets/controls/float-slider.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * FloatSlider widget - renders a floating point slider.
  *
diff --git a/registry/widgets/controls/gridbox-widget.tsx b/registry/widgets/controls/gridbox-widget.tsx
index 71d414d..f6a4cbe 100644
--- a/registry/widgets/controls/gridbox-widget.tsx
+++ b/registry/widgets/controls/gridbox-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * GridBox widget - CSS grid container.
  *
diff --git a/registry/widgets/controls/hbox-widget.tsx b/registry/widgets/controls/hbox-widget.tsx
index cca35ad..7a7e2d2 100644
--- a/registry/widgets/controls/hbox-widget.tsx
+++ b/registry/widgets/controls/hbox-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * HBox widget - horizontal flex container.
  *
diff --git a/registry/widgets/controls/html-math-widget.tsx b/registry/widgets/controls/html-math-widget.tsx
index a642563..349710b 100644
--- a/registry/widgets/controls/html-math-widget.tsx
+++ b/registry/widgets/controls/html-math-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * HTMLMath widget - renders HTML content with LaTeX math support.
  *
diff --git a/registry/widgets/controls/html-widget.tsx b/registry/widgets/controls/html-widget.tsx
index 0abcb21..f56e917 100644
--- a/registry/widgets/controls/html-widget.tsx
+++ b/registry/widgets/controls/html-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * HTML widget - renders arbitrary HTML content.
  *
diff --git a/registry/widgets/controls/image-widget.tsx b/registry/widgets/controls/image-widget.tsx
index f4767c0..269d121 100644
--- a/registry/widgets/controls/image-widget.tsx
+++ b/registry/widgets/controls/image-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Image widget - displays images from the kernel.
  *
diff --git a/registry/widgets/controls/int-progress.tsx b/registry/widgets/controls/int-progress.tsx
index 7edc0b4..a0e4f0b 100644
--- a/registry/widgets/controls/int-progress.tsx
+++ b/registry/widgets/controls/int-progress.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * IntProgress widget - renders an integer progress bar.
  *
diff --git a/registry/widgets/controls/int-range-slider.tsx b/registry/widgets/controls/int-range-slider.tsx
index a6122f3..36a9913 100644
--- a/registry/widgets/controls/int-range-slider.tsx
+++ b/registry/widgets/controls/int-range-slider.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * IntRangeSlider widget - renders a dual-handle range slider for integers.
  *
diff --git a/registry/widgets/controls/int-slider.tsx b/registry/widgets/controls/int-slider.tsx
index de28597..cf73b82 100644
--- a/registry/widgets/controls/int-slider.tsx
+++ b/registry/widgets/controls/int-slider.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * IntSlider widget - renders an integer slider.
  *
diff --git a/registry/widgets/controls/label-widget.tsx b/registry/widgets/controls/label-widget.tsx
index 8155aa4..509a6c6 100644
--- a/registry/widgets/controls/label-widget.tsx
+++ b/registry/widgets/controls/label-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Label widget - renders plain text content.
  *
diff --git a/registry/widgets/controls/link-widget.tsx b/registry/widgets/controls/link-widget.tsx
index ddba0df..b36d1dc 100644
--- a/registry/widgets/controls/link-widget.tsx
+++ b/registry/widgets/controls/link-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Link widgets — frontend-only property synchronization.
  *
diff --git a/registry/widgets/controls/radio-buttons-widget.tsx b/registry/widgets/controls/radio-buttons-widget.tsx
index 20c1743..9c4b6f5 100644
--- a/registry/widgets/controls/radio-buttons-widget.tsx
+++ b/registry/widgets/controls/radio-buttons-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * RadioButtons widget - renders a group of radio buttons.
  *
diff --git a/registry/widgets/controls/select-multiple-widget.tsx b/registry/widgets/controls/select-multiple-widget.tsx
index 22ada8e..bcfbd4d 100644
--- a/registry/widgets/controls/select-multiple-widget.tsx
+++ b/registry/widgets/controls/select-multiple-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * SelectMultiple widget - renders a multi-select listbox.
  *
diff --git a/registry/widgets/controls/select-widget.tsx b/registry/widgets/controls/select-widget.tsx
index 7153185..5cbe168 100644
--- a/registry/widgets/controls/select-widget.tsx
+++ b/registry/widgets/controls/select-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Select widget - renders a single-selection listbox.
  *
diff --git a/registry/widgets/controls/selection-range-slider-widget.tsx b/registry/widgets/controls/selection-range-slider-widget.tsx
index da6a609..f0a2ff1 100644
--- a/registry/widgets/controls/selection-range-slider-widget.tsx
+++ b/registry/widgets/controls/selection-range-slider-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * SelectionRangeSlider widget - range slider that selects from discrete options.
  *
diff --git a/registry/widgets/controls/selection-slider-widget.tsx b/registry/widgets/controls/selection-slider-widget.tsx
index a5e42fc..3048494 100644
--- a/registry/widgets/controls/selection-slider-widget.tsx
+++ b/registry/widgets/controls/selection-slider-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * SelectionSlider widget - slider that selects from discrete options.
  *
diff --git a/registry/widgets/controls/stack-widget.tsx b/registry/widgets/controls/stack-widget.tsx
index c10b229..ec401ec 100644
--- a/registry/widgets/controls/stack-widget.tsx
+++ b/registry/widgets/controls/stack-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Stack widget - single-child container showing one child at a time.
  *
diff --git a/registry/widgets/controls/tab-widget.tsx b/registry/widgets/controls/tab-widget.tsx
index 6789a62..967d3a7 100644
--- a/registry/widgets/controls/tab-widget.tsx
+++ b/registry/widgets/controls/tab-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Tab widget - tabbed panel container.
  *
diff --git a/registry/widgets/controls/toggle-button-widget.tsx b/registry/widgets/controls/toggle-button-widget.tsx
index 2659567..28a665f 100644
--- a/registry/widgets/controls/toggle-button-widget.tsx
+++ b/registry/widgets/controls/toggle-button-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * ToggleButton widget - renders a single toggle button.
  *
diff --git a/registry/widgets/controls/toggle-buttons-widget.tsx b/registry/widgets/controls/toggle-buttons-widget.tsx
index 0a4e567..edec4ab 100644
--- a/registry/widgets/controls/toggle-buttons-widget.tsx
+++ b/registry/widgets/controls/toggle-buttons-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * ToggleButtons widget - renders a group of toggle buttons (single selection).
  *
diff --git a/registry/widgets/controls/valid-widget.tsx b/registry/widgets/controls/valid-widget.tsx
index 70fafd5..af0a584 100644
--- a/registry/widgets/controls/valid-widget.tsx
+++ b/registry/widgets/controls/valid-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Valid widget - displays a validation indicator (checkmark or X).
  *
diff --git a/registry/widgets/controls/vbox-widget.tsx b/registry/widgets/controls/vbox-widget.tsx
index 879a837..ea1239d 100644
--- a/registry/widgets/controls/vbox-widget.tsx
+++ b/registry/widgets/controls/vbox-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * VBox widget - vertical flex container.
  *
diff --git a/registry/widgets/controls/video-widget.tsx b/registry/widgets/controls/video-widget.tsx
index 37599e3..206f11c 100644
--- a/registry/widgets/controls/video-widget.tsx
+++ b/registry/widgets/controls/video-widget.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Video widget - plays video from the kernel.
  *
diff --git a/registry/widgets/ipycanvas/index.ts b/registry/widgets/ipycanvas/index.ts
index 89297db..74167d5 100644
--- a/registry/widgets/ipycanvas/index.ts
+++ b/registry/widgets/ipycanvas/index.ts
@@ -1,10 +1,3 @@
-/**
- * ipycanvas widget registration.
- *
- * Registers CanvasModel and CanvasManagerModel with the widget registry.
- * Import this module to enable rendering of ipycanvas widgets.
- */
-
 import { registerWidget } from "../widget-registry";
 import { CanvasManagerWidget, CanvasWidget } from "./canvas-widget";
 
diff --git a/registry/widgets/use-comm-router.ts b/registry/widgets/use-comm-router.ts
index 2f87c17..21ee3ca 100644
--- a/registry/widgets/use-comm-router.ts
+++ b/registry/widgets/use-comm-router.ts
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Comm Protocol Router Hook
  *
diff --git a/registry/widgets/use-layout-styles.ts b/registry/widgets/use-layout-styles.ts
index f7656e9..5de2a84 100644
--- a/registry/widgets/use-layout-styles.ts
+++ b/registry/widgets/use-layout-styles.ts
@@ -1,5 +1,3 @@
-"use client";
-
 import type { CSSProperties } from "react";
 import { useMemo } from "react";
 import {
diff --git a/registry/widgets/widget-view.tsx b/registry/widgets/widget-view.tsx
index 9092401..1d65489 100644
--- a/registry/widgets/widget-view.tsx
+++ b/registry/widgets/widget-view.tsx
@@ -1,5 +1,3 @@
-"use client";
-
 /**
  * Universal widget view component.
  *