diff --git a/frontend/src/app/plugins/library.cljs b/frontend/src/app/plugins/library.cljs
index 9fb646f205..5839ed57a4 100644
--- a/frontend/src/app/plugins/library.cljs
+++ b/frontend/src/app/plugins/library.cljs
@@ -1043,7 +1043,12 @@
               ids (into #{} (map #(obj/get % "$id")) shapes)]
           (st/emit! (-> (dwl/add-component id-ref ids)
                         (se/add-event plugin-id)))
-          (lib-component-proxy plugin-id file-id @id-ref))))
+          ;; add-component only sets id-ref when it actually creates a
+          ;; component; an empty selection or shapes that can't form one
+          ;; leave it nil, so reject instead of returning a broken proxy.
+          (if-let [id @id-ref]
+            (lib-component-proxy plugin-id file-id id)
+            (u/not-valid plugin-id :createComponent "Cannot create a component from the given shapes")))))
 
     ;; Plugin data
     :getPluginData
diff --git a/plugins/CHANGELOG.md b/plugins/CHANGELOG.md
index 323e8319ab..eaae151372 100644
--- a/plugins/CHANGELOG.md
+++ b/plugins/CHANGELOG.md
@@ -6,6 +6,7 @@
 
 ### 🩹 Fixes
 
+- **plugins-runtime**: `Library.createComponent()` now rejects invalid input (an empty shape list, or a shape inside a component copy) with a validation error instead of returning a component proxy pointing at nothing.
 - **plugins-runtime**: Setting an individual padding/margin side (`leftPadding`, `topMargin`, …) now re-derives the padding/margin type, switching to `multiple` when the four sides stop being symmetric (so the value is actually painted) and back to `simple` once top/bottom and left/right are mirrored again.
 
 ## 1.5.0 (2026-07-08)
diff --git a/plugins/apps/plugin-api-test-suite/src/tests/library.test.ts b/plugins/apps/plugin-api-test-suite/src/tests/library.test.ts
index 7d3a8ccf0a..32da4f5a59 100644
--- a/plugins/apps/plugin-api-test-suite/src/tests/library.test.ts
+++ b/plugins/apps/plugin-api-test-suite/src/tests/library.test.ts
@@ -1,6 +1,6 @@
 import { expect } from '../framework/expect';
 import { describe, test } from '../framework/registry';
-import type { Text } from '@penpot/plugin-types';
+import type { Board, Text } from '@penpot/plugin-types';
 import type { TestContext } from '../framework/types';
 import { PNG_1X1 } from './fixtures';
 
@@ -310,5 +310,59 @@ describe('Library', () => {
       expect(instance).toBeDefined();
       expect(typeof instance.id).toBe('string');
     });
+
+    // Reported (via MCP): create a page-root shape (rectangle / ellipse / text),
+    // save it as a component, then use it from Assets — the component root was
+    // said to be a plain shape instead of a board/component. This does not
+    // reproduce: a lone page-root shape is wrapped in a board and that board
+    // becomes the component (main-instance) root. Pin the invariant for the
+    // exact repro.
+    test('createComponent wraps a page-root shape in a board component root', (ctx) => {
+      // A genuine page-root shape: created but NOT placed inside any board.
+      const rect = ctx.penpot.createRectangle();
+      const comp = ctx.penpot.library.local.createComponent([rect]);
+
+      const main = comp.mainInstance() as Board;
+      expect(main.type).toBe('board');
+      expect(main.isComponentRoot()).toBeTruthy();
+      expect(main.isComponentMainInstance()).toBeTruthy();
+      expect(main.children.some((c) => c.id === rect.id)).toBe(true);
+
+      const errors = ctx.penpot.currentFile?.validate() ?? [];
+      expect(errors.map((e) => e.code)).toEqual([]);
+
+      // The generated main instance lands at the page root (outside ctx.board);
+      // tuck it under the scratch board so teardown removes it.
+      ctx.board.appendChild(main);
+    });
+
+    // createComponent must reject inputs that cannot form a component rather
+    // than succeeding silently or crashing. Both cases below currently surface
+    // an INTERNAL assertion ("Assert failed: (uuid? id)"): the operation is a
+    // no-op, so the returned LibraryComponent proxy is built from a nil id. It
+    // should be a clean rejection (or a null return) instead — and in a release
+    // build, where the assertion is elided, the caller gets a broken component
+    // proxy pointing at nothing. The file must stay valid regardless.
+    test('createComponent with no shapes is rejected', (ctx) => {
+      expect(() => ctx.penpot.library.local.createComponent([])).toThrow();
+      const errors = ctx.penpot.currentFile?.validate() ?? [];
+      expect(errors.map((e) => e.code)).toEqual([]);
+    });
+
+    test('createComponent from a shape inside a component copy is rejected', (ctx) => {
+      const rect = ctx.penpot.createRectangle();
+      ctx.board.appendChild(rect);
+      const source = ctx.penpot.library.local.createComponent([rect]);
+      const copy = source.instance() as Board;
+      ctx.board.appendChild(copy);
+      const copyChild = copy.children[0];
+      expect(copyChild).toBeDefined();
+
+      expect(() =>
+        ctx.penpot.library.local.createComponent([copyChild]),
+      ).toThrow();
+      const errors = ctx.penpot.currentFile?.validate() ?? [];
+      expect(errors.map((e) => e.code)).toEqual([]);
+    });
   });
 });