diff --git a/packages/core/src/clipboard.ts b/packages/core/src/clipboard.ts
index 368601f84..554f39106 100644
--- a/packages/core/src/clipboard.ts
+++ b/packages/core/src/clipboard.ts
@@ -420,7 +420,7 @@ export function buildFigmaClipboardHTML(nodes: SceneNode[], graph: SceneGraph):
     type: 'NODE_CHANGES',
     sessionID: 0,
     ackID: 0,
-    pasteID: crypto.getRandomValues(new Uint32Array(1))[0],
+    pasteID: crypto.getRandomValues(new Int32Array(1))[0],
     pasteFileKey: 'openpencil',
     nodeChanges
   }
diff --git a/src/components/AppToast.vue b/src/components/AppToast.vue
index 407e07a6f..87275f69e 100644
--- a/src/components/AppToast.vue
+++ b/src/components/AppToast.vue
@@ -1,15 +1,20 @@
 <script setup lang="ts">
-import { ToastProvider, ToastRoot, ToastDescription, ToastViewport } from 'reka-ui'
+import { ToastProvider, ToastRoot, ToastDescription, ToastViewport, ToastClose } from 'reka-ui'
+
+import { useClipboard } from '@vueuse/core'
 
 import { toast } from '@/composables/use-toast'
+
+const { copy, copied } = useClipboard({ copiedDuring: 1500 })
 </script>
 
 <template>
-  <ToastProvider :duration="toast.TOAST_DURATION" swipe-direction="up">
+  <ToastProvider swipe-direction="up">
     <ToastRoot
       v-for="t in toast.toasts.value"
       :key="t.id"
-      class="flex items-center gap-1.5 rounded-md px-2.5 py-1.5 text-xs text-white shadow-md data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=open]:fade-in data-[state=open]:slide-in-from-top-1 data-[state=closed]:fade-out data-[state=closed]:slide-out-to-top-1 data-[swipe=move]:translate-y-[var(--reka-toast-swipe-move-y)] data-[swipe=cancel]:translate-y-0 data-[swipe=cancel]:transition-transform"
+      :duration="t.variant === 'error' ? 0 : toast.TOAST_DURATION"
+      class="flex max-w-sm items-start gap-1.5 rounded-md px-2.5 py-1.5 text-xs text-white shadow-md data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=open]:fade-in data-[state=open]:slide-in-from-top-1 data-[state=closed]:fade-out data-[state=closed]:slide-out-to-top-1 data-[swipe=move]:translate-y-[var(--reka-toast-swipe-move-y)] data-[swipe=cancel]:translate-y-0 data-[swipe=cancel]:transition-transform"
       :class="t.variant === 'error' ? 'bg-red-600' : 'bg-blue-600'"
       @update:open="
         (open) => {
@@ -17,9 +22,24 @@ import { toast } from '@/composables/use-toast'
         }
       "
     >
-      <icon-lucide-check v-if="t.variant === 'default'" class="size-3 shrink-0" />
-      <icon-lucide-alert-triangle v-else class="size-3 shrink-0" />
-      <ToastDescription>{{ t.message }}</ToastDescription>
+      <icon-lucide-check v-if="t.variant === 'default'" class="mt-0.5 size-3 shrink-0" />
+      <icon-lucide-alert-triangle v-else class="mt-0.5 size-3 shrink-0" />
+      <ToastDescription class="min-w-0 flex-1 select-text">{{ t.message }}</ToastDescription>
+      <button
+        v-if="t.variant === 'error'"
+        class="mt-0.5 shrink-0 cursor-pointer rounded p-0.5 opacity-70 hover:opacity-100"
+        :title="copied ? 'Copied!' : 'Copy error'"
+        @click="copy(t.message)"
+      >
+        <icon-lucide-check v-if="copied" class="size-3" />
+        <icon-lucide-copy v-else class="size-3" />
+      </button>
+      <ToastClose
+        v-if="t.variant === 'error'"
+        class="mt-0.5 shrink-0 cursor-pointer rounded p-0.5 opacity-70 hover:opacity-100"
+      >
+        <icon-lucide-x class="size-3" />
+      </ToastClose>
     </ToastRoot>
 
     <ToastViewport
diff --git a/tests/engine/clipboard.test.ts b/tests/engine/clipboard.test.ts
index 89187b347..036fa457c 100644
--- a/tests/engine/clipboard.test.ts
+++ b/tests/engine/clipboard.test.ts
@@ -1,10 +1,12 @@
-import { describe, expect, it } from 'bun:test'
+import { beforeAll, describe, expect, it } from 'bun:test'
 
 import {
   parseFigmaClipboard,
   importClipboardNodes,
   figmaNodesBounds,
+  buildFigmaClipboardHTML,
 } from '../../packages/core/src/clipboard'
+import { initCodec } from '../../packages/core/src/kiwi/codec'
 import { SceneGraph, type SceneNode } from '../../packages/core/src/scene-graph'
 
 function makeClipboardHtml(nodeChanges: unknown[], meta = { fileKey: 'test', pasteID: 1, dataType: 'scene' }) {
@@ -334,3 +336,115 @@ describe('figmaNodesBounds', () => {
     expect(figmaNodesBounds(nodes)).toBeNull()
   })
 })
+
+describe('buildFigmaClipboardHTML', () => {
+  beforeAll(async () => {
+    await initCodec()
+  })
+
+  it('encodes a simple frame without throwing', () => {
+    const graph = new SceneGraph()
+    const page = graph.getPages()[0]
+    const frame = graph.createNode('FRAME', page.id, {
+      name: 'Card',
+      x: 0, y: 0, width: 300, height: 200,
+      fills: [{ type: 'SOLID', color: { r: 1, g: 1, b: 1, a: 1 }, opacity: 1, visible: true }],
+    })
+
+    const html = buildFigmaClipboardHTML([frame], graph)
+    expect(html).toContain('figmeta')
+    expect(html).toContain('figma')
+  })
+
+  it('encodes text nodes with style runs', () => {
+    const graph = new SceneGraph()
+    const page = graph.getPages()[0]
+    const text = graph.createNode('TEXT', page.id, {
+      name: 'Styled',
+      x: 0, y: 0, width: 200, height: 24,
+      text: 'Hello World',
+      fontFamily: 'Inter',
+      fontWeight: 400,
+      fontSize: 16,
+      styleRuns: [
+        { start: 0, length: 5, style: { fontWeight: 700 } },
+        { start: 6, length: 5, style: { fontWeight: 400, italic: true } },
+      ],
+    })
+
+    const html = buildFigmaClipboardHTML([text], graph)
+    expect(html).toContain('figmeta')
+  })
+
+  it('encodes auto-layout frames', () => {
+    const graph = new SceneGraph()
+    const page = graph.getPages()[0]
+    const frame = graph.createNode('FRAME', page.id, {
+      name: 'Row',
+      x: 0, y: 0, width: 400, height: 100,
+      layoutMode: 'HORIZONTAL',
+      itemSpacing: 16,
+      paddingTop: 12, paddingRight: 12, paddingBottom: 12, paddingLeft: 12,
+      primaryAxisSizing: 'HUG',
+      counterAxisSizing: 'FIXED',
+    })
+    graph.createNode('RECTANGLE', frame.id, {
+      name: 'Child',
+      x: 0, y: 0, width: 50, height: 50,
+    })
+
+    const html = buildFigmaClipboardHTML([frame], graph)
+    expect(html).toContain('figmeta')
+  })
+
+  it('roundtrips: encode then decode back', async () => {
+    const graph = new SceneGraph()
+    const page = graph.getPages()[0]
+    const frame = graph.createNode('FRAME', page.id, {
+      name: 'Analytics Overview',
+      x: 0, y: 0, width: 300, height: 200,
+      layoutMode: 'VERTICAL',
+      itemSpacing: 8,
+      paddingTop: 20, paddingRight: 20, paddingBottom: 20, paddingLeft: 20,
+      fills: [{ type: 'SOLID', color: { r: 1, g: 1, b: 1, a: 1 }, opacity: 1, visible: true }],
+      cornerRadius: 12,
+    })
+    graph.createNode('TEXT', frame.id, {
+      name: 'Title',
+      x: 0, y: 0, width: 260, height: 24,
+      text: 'Analytics Overview',
+      fontFamily: 'Inter',
+      fontWeight: 600,
+      fontSize: 18,
+    })
+    graph.createNode('TEXT', frame.id, {
+      name: 'Subtitle',
+      x: 0, y: 0, width: 260, height: 40,
+      text: 'Track your key metrics and performance indicators in real time.',
+      fontFamily: 'Inter',
+      fontWeight: 400,
+      fontSize: 14,
+    })
+
+    const html = buildFigmaClipboardHTML([frame], graph)
+    expect(html).not.toBeNull()
+
+    const parsed = await parseFigmaClipboard(html!)
+    expect(parsed).not.toBeNull()
+    expect(parsed!.nodes.length).toBeGreaterThan(0)
+
+    const graph2 = new SceneGraph()
+    const page2 = graph2.getPages()[0]
+    const created = importClipboardNodes(parsed!.nodes, graph2, page2.id)
+    expect(created).toHaveLength(1)
+
+    const imported = graph2.getNode(created[0])!
+    expect(imported.name).toBe('Analytics Overview')
+    expect(imported.cornerRadius).toBe(12)
+
+    const children = graph2.getChildren(imported.id)
+    expect(children).toHaveLength(2)
+    expect(children[0].text).toBe('Analytics Overview')
+    expect(children[1].text).toContain('Track your key metrics')
+  })
+})