diff --git a/tests/e2e/app/menu.spec.ts b/tests/e2e/app/menu.spec.ts
index 16302ca5f..0752797ad 100644
--- a/tests/e2e/app/menu.spec.ts
+++ b/tests/e2e/app/menu.spec.ts
@@ -101,7 +101,8 @@ test('Duplicate via Edit menu works', async () => {
   await canvas.drawRect(300, 300, 80, 80)
 
   const countBefore = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getChildren(store.state.currentPageId).length
   })
 
@@ -110,7 +111,8 @@ test('Duplicate via Edit menu works', async () => {
   await canvas.waitForRender()
 
   const countAfter = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getChildren(store.state.currentPageId).length
   })
 
diff --git a/tests/e2e/canvas/frame-overlays.spec.ts b/tests/e2e/canvas/frame-overlays.spec.ts
index cec096261..a55af39c9 100644
--- a/tests/e2e/canvas/frame-overlays.spec.ts
+++ b/tests/e2e/canvas/frame-overlays.spec.ts
@@ -30,7 +30,8 @@ async function expectCanvas(name: string) {
 
 async function createOverlayDemo(rotation: number) {
   await page.evaluate((frameRotation) => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
 
     const frame = store.graph.createNode('FRAME', pageId, {
@@ -102,7 +103,8 @@ test('rotation preview updates frame labels before mouse up', async () => {
   await createOverlayDemo(0)
 
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const frameId = [...store.state.selectedIds][0]
     store.state.rotationPreview = { nodeId: frameId, angle: 28 }
     store.requestRepaint()
diff --git a/tests/e2e/canvas/manipulation.spec.ts b/tests/e2e/canvas/manipulation.spec.ts
index b5d3dfda0..50b556003 100644
--- a/tests/e2e/canvas/manipulation.spec.ts
+++ b/tests/e2e/canvas/manipulation.spec.ts
@@ -87,7 +87,8 @@ test('resize corner handle drag increases node dimensions', async () => {
   expect(before).not.toBeNull()
 
   const viewport = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     const n = store.graph.getNode(id)
     if (!n) return null
@@ -131,7 +132,8 @@ test('rotation handle drag rotates node', async () => {
   const initialRotation = before!.rotation ?? 0
 
   const viewport = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     const n = store.graph.getNode(id)
     if (!n) return null
@@ -183,7 +185,8 @@ async function setupFrameChild(rotation: number) {
   await canvas.clearCanvas()
 
   const setup = await page.evaluate((frameRotation) => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const frameId = store.createShape('FRAME', 180, 160, 240, 160)
     if (!frameId) return null
     store.updateNode(frameId, { rotation: frameRotation })
@@ -200,7 +203,8 @@ async function setupFrameChild(rotation: number) {
   await canvas.waitForRender()
 
   const state = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
     const pageNode = store.graph.getNode(pageId)
     const frame = pageNode?.childIds
@@ -278,7 +282,8 @@ test('rotation drag exposes live rotation preview state', async () => {
   await canvas.waitForRender()
 
   const viewport = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     const n = store.graph.getNode(id)
     if (!n) return null
diff --git a/tests/e2e/clipboard/copy-paste.spec.ts b/tests/e2e/clipboard/copy-paste.spec.ts
index 9aef35b69..591cc3f9f 100644
--- a/tests/e2e/clipboard/copy-paste.spec.ts
+++ b/tests/e2e/clipboard/copy-paste.spec.ts
@@ -20,7 +20,8 @@ test.afterAll(async () => {
 
 function getPageChildCount() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getChildren(store.state.currentPageId).length
   })
 }
@@ -31,7 +32,8 @@ function getSelectedCount() {
 
 function getSelectedNodes() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return [...store.state.selectedIds].map((id) => {
       const n = store.graph.getNode(id)!
       return {
@@ -55,7 +57,8 @@ test('copy + paste via store duplicates a shape', async () => {
   const countBefore = await getPageChildCount()
 
   await page.evaluate(async () => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const data = new DataTransfer()
     await store.writeCopyData(data)
     const html = data.getData('text/html')
@@ -92,7 +95,8 @@ test('⌘D duplicates in place', async () => {
 test('duplicate preserves fills', async () => {
   // Set a custom fill on the selected node
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     store.updateNodeWithUndo(
       id,
@@ -127,7 +131,8 @@ test('cut removes original', async () => {
 
   // Cut via store
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const data = new DataTransfer()
     store.writeCopyData(data)
     store.deleteSelected()
diff --git a/tests/e2e/code/panel.spec.ts b/tests/e2e/code/panel.spec.ts
index 05ec8c8cc..8b37c0665 100644
--- a/tests/e2e/code/panel.spec.ts
+++ b/tests/e2e/code/panel.spec.ts
@@ -99,7 +99,8 @@ test('deselecting shows empty state again', async () => {
 test('selecting a frame shows Frame in JSX', async () => {
   // Create a frame via store to avoid click-targeting issues
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = store.createShape('FRAME', 300, 100, 200, 200)
     store.select([id])
   })
diff --git a/tests/e2e/color-picker/basic.spec.ts b/tests/e2e/color-picker/basic.spec.ts
index 05af45481..4a966c86e 100644
--- a/tests/e2e/color-picker/basic.spec.ts
+++ b/tests/e2e/color-picker/basic.spec.ts
@@ -20,7 +20,8 @@ test.afterAll(async () => {
 
 async function getSelectedFill() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     if (!id) return null
     const node = store.graph.getNode(id)
diff --git a/tests/e2e/color-picker/demo-card.spec.ts b/tests/e2e/color-picker/demo-card.spec.ts
index 6069797c1..c6bc5eede 100644
--- a/tests/e2e/color-picker/demo-card.spec.ts
+++ b/tests/e2e/color-picker/demo-card.spec.ts
@@ -26,7 +26,8 @@ async function selectDemoCard(page: Parameters<typeof test>[0]['page'], canvas:
   await canvas.waitForInit()
 
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const nodes = Array.from(store.graph.nodes.values())
     const card =
       nodes.find((node) => node.name === 'Card' && node.type === 'COMPONENT') ??
@@ -49,7 +50,8 @@ async function selectDemoCard(page: Parameters<typeof test>[0]['page'], canvas:
 
 async function getSelectedFill(page: Parameters<typeof test>[0]['page']) {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     const node = store.graph.getNode(id)
     return node
diff --git a/tests/e2e/components.spec.ts b/tests/e2e/components.spec.ts
index b7815f910..ad537e4b4 100644
--- a/tests/e2e/components.spec.ts
+++ b/tests/e2e/components.spec.ts
@@ -20,7 +20,8 @@ test.afterAll(async () => {
 
 function getNodeById(id: string) {
   return page.evaluate((nodeId) => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const n = store.graph.getNode(nodeId)
     if (!n) return null
     return { type: n.type, name: n.name, componentId: n.componentId, childIds: n.childIds }
@@ -33,7 +34,8 @@ function getSelectedIds() {
 
 function getPageChildren() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getChildren(store.state.currentPageId).map((n) => ({
       id: n.id,
       type: n.type,
@@ -71,7 +73,8 @@ test('component visible in layers panel', async () => {
   expect(count).toBeGreaterThan(0)
 
   const types = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getChildren(store.state.currentPageId).map((n) => n.type)
   })
   expect(types).toContain('COMPONENT')
@@ -84,7 +87,8 @@ test('create instance from component (context menu)', async () => {
 
   // Use store directly to create instance
   await page.evaluate((compId) => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     store.createInstanceFromComponent(compId, 300, 100)
   }, comp!.id)
   await canvas.waitForRender()
@@ -127,7 +131,8 @@ test('modifying component propagates to instance', async () => {
 
   // Change component fill
   await page.evaluate((id) => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     store.updateNodeWithUndo(
       id,
       {
@@ -150,7 +155,8 @@ test('modifying component propagates to instance', async () => {
   const children = await getPageChildren()
   const instance = children.find((c) => c.type === 'INSTANCE')!
   const instanceNode = await page.evaluate((id) => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const n = store.graph.getNode(id)
     const child = store.graph.getChildren(id)[0]
     return child ? { fills: child.fills } : { fills: n?.fills ?? [] }
diff --git a/tests/e2e/context-menu/basic.spec.ts b/tests/e2e/context-menu/basic.spec.ts
index d75a967aa..c83a3b93b 100644
--- a/tests/e2e/context-menu/basic.spec.ts
+++ b/tests/e2e/context-menu/basic.spec.ts
@@ -20,7 +20,8 @@ test.afterAll(async () => {
 
 function getPageChildren() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getChildren(store.state.currentPageId).map((n) => ({
       id: n.id,
       type: n.type,
@@ -117,7 +118,8 @@ test('toggle visibility via context menu', async () => {
 
   // Toggle back: select via store since invisible nodes can't be hit-tested
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     store.toggleVisibility()
   })
   await canvas.waitForRender()
@@ -177,7 +179,8 @@ test('group via context menu', async () => {
 test('ungroup via store after context-menu group', async () => {
   // Groups are click-through, so ungroup via store instead
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const group = store.graph.getChildren(store.state.currentPageId).find((n) => n.type === 'GROUP')
     if (group) store.select([group.id])
     store.ungroupSelected()
diff --git a/tests/e2e/design/panel.spec.ts b/tests/e2e/design/panel.spec.ts
index c48f00c82..a47c7bbbb 100644
--- a/tests/e2e/design/panel.spec.ts
+++ b/tests/e2e/design/panel.spec.ts
@@ -44,7 +44,8 @@ function effectsSection() {
 
 function getNode(id: string) {
   return page.evaluate((nodeId) => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const n = store.graph.getNode(nodeId)
     if (!n) return null
     return {
@@ -64,7 +65,8 @@ function getNode(id: string) {
 
 function getSelectedId() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return [...store.state.selectedIds][0] ?? null
   })
 }
diff --git a/tests/e2e/editor/duplicate-undo.spec.ts b/tests/e2e/editor/duplicate-undo.spec.ts
index 7e92b4deb..ff13aa3a2 100644
--- a/tests/e2e/editor/duplicate-undo.spec.ts
+++ b/tests/e2e/editor/duplicate-undo.spec.ts
@@ -24,7 +24,8 @@ test.beforeEach(async () => {
 
 async function rectangleCount() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return [...store.graph.nodes.values()].filter((node) => node.type === 'RECTANGLE').length
   })
 }
@@ -35,7 +36,8 @@ async function layerItems() {
 
 async function historyState() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return {
       canUndo: store.undo.canUndo,
       canRedo: store.undo.canRedo,
diff --git a/tests/e2e/fonts/settings.spec.ts b/tests/e2e/fonts/settings.spec.ts
index 3c476a7f5..2a3f7b4ca 100644
--- a/tests/e2e/fonts/settings.spec.ts
+++ b/tests/e2e/fonts/settings.spec.ts
@@ -8,7 +8,8 @@ test('font settings popover is available from typography panel', async ({ page }
   await canvas.waitForInit()
 
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = store.createShape('TEXT', 120, 120, 240, 40)
     store.updateNode(id, { characters: 'Font settings smoke' })
     store.select([id])
diff --git a/tests/e2e/keyboard/shortcuts.spec.ts b/tests/e2e/keyboard/shortcuts.spec.ts
index f513d1c85..70a0cbfff 100644
--- a/tests/e2e/keyboard/shortcuts.spec.ts
+++ b/tests/e2e/keyboard/shortcuts.spec.ts
@@ -28,7 +28,8 @@ function getSelectedCount() {
 
 function getPageChildren() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getChildren(store.state.currentPageId).map((n) => ({
       id: n.id,
       type: n.type,
@@ -219,7 +220,8 @@ test.describe('zoom shortcuts', () => {
 
     // Set zoom to something other than 100%
     await page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       store.state.zoom = 2
     })
     await canvas.waitForRender()
@@ -300,14 +302,16 @@ test.describe('auto-layout shortcut', () => {
 
     // Change to frame type for auto-layout
     await page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const nodes = [...store.state.selectedIds]
       if (nodes[0]) store.updateNode(nodes[0], { type: 'FRAME' })
     })
     await canvas.waitForRender()
 
     const layoutBefore = await page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const nodes = [...store.state.selectedIds]
       return store.graph.getNode(nodes[0])?.layoutMode
     })
@@ -317,7 +321,8 @@ test.describe('auto-layout shortcut', () => {
     await canvas.waitForRender()
 
     const layoutAfter = await page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const nodes = [...store.state.selectedIds]
       return store.graph.getNode(nodes[0])?.layoutMode
     })
@@ -328,7 +333,8 @@ test.describe('auto-layout shortcut', () => {
     await canvas.waitForRender()
 
     const layoutFinal = await page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const nodes = [...store.state.selectedIds]
       return store.graph.getNode(nodes[0])?.layoutMode
     })
diff --git a/tests/e2e/pages/multi-page.spec.ts b/tests/e2e/pages/multi-page.spec.ts
index be1b3ecf2..6a74606a2 100644
--- a/tests/e2e/pages/multi-page.spec.ts
+++ b/tests/e2e/pages/multi-page.spec.ts
@@ -20,7 +20,8 @@ test.afterAll(async () => {
 
 function getPages() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getPages().map((p) => ({ id: p.id, name: p.name }))
   })
 }
@@ -31,7 +32,8 @@ function getCurrentPageId() {
 
 function getPageChildCount() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getChildren(store.state.currentPageId).length
   })
 }
@@ -120,7 +122,8 @@ test('delete current page switches to adjacent', async () => {
   const deletingId = await getCurrentPageId()
 
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     store.deletePage(store.state.currentPageId)
   })
   await canvas.waitForRender()
@@ -191,7 +194,8 @@ test('cannot delete the last page', async () => {
   let pages = await getPages()
   while (pages.length > 1) {
     await page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       store.deletePage(store.state.currentPageId)
     })
     await canvas.waitForRender()
@@ -202,7 +206,8 @@ test('cannot delete the last page', async () => {
 
   // Try deleting the last one — should be a no-op
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     store.deletePage(store.state.currentPageId)
   })
   await canvas.waitForRender()
diff --git a/tests/e2e/perf/basic.spec.ts b/tests/e2e/perf/basic.spec.ts
index de0b88d13..c13f0a866 100644
--- a/tests/e2e/perf/basic.spec.ts
+++ b/tests/e2e/perf/basic.spec.ts
@@ -15,7 +15,8 @@ test.describe('Render performance', () => {
     await helper.waitForInit()
 
     await page.evaluate((count: number) => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const arr = new Uint8Array(count * 3)
       crypto.getRandomValues(arr)
       const cols = Math.ceil(Math.sqrt(count))
@@ -86,7 +87,8 @@ test.describe('Render performance', () => {
 
   test('benchmark: synchronous render throughput', async () => {
     const results = await helper.page.evaluate((iterations: number) => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const renderer = store.renderer!
 
       function setupRenderer() {
@@ -173,7 +175,8 @@ test.describe('Render performance', () => {
 
     const results = await helper.page.evaluate(
       ({ count, iterations }) => {
-        const store = window.__OPEN_PENCIL_STORE__!
+        const store = window.__OPEN_PENCIL_STORE__
+        if (!store) throw new Error('OpenPencil store not initialized')
         const renderer = store.renderer!
         const graph = store.graph
         const pageId = store.state.currentPageId
diff --git a/tests/e2e/properties/corner-stroke-toggles.spec.ts b/tests/e2e/properties/corner-stroke-toggles.spec.ts
index 79a93ba6a..2962f9d53 100644
--- a/tests/e2e/properties/corner-stroke-toggles.spec.ts
+++ b/tests/e2e/properties/corner-stroke-toggles.spec.ts
@@ -20,7 +20,8 @@ test.afterAll(async () => {
 
 async function getSelectedNodeFlags() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     if (!id) return null
     const n = store.graph.getNode(id)
diff --git a/tests/e2e/properties/effects.spec.ts b/tests/e2e/properties/effects.spec.ts
index 023fd3124..bde686716 100644
--- a/tests/e2e/properties/effects.spec.ts
+++ b/tests/e2e/properties/effects.spec.ts
@@ -30,7 +30,8 @@ async function expectCanvas(name: string) {
 
 test('drop shadow on white card', async () => {
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
     store.graph.createNode('FRAME', pageId, {
       name: 'Card',
@@ -60,7 +61,8 @@ test('drop shadow on white card', async () => {
 
 test('drop shadow with spread', async () => {
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
     store.graph.createNode('FRAME', pageId, {
       name: 'Card',
@@ -90,7 +92,8 @@ test('drop shadow with spread', async () => {
 
 test('inner shadow', async () => {
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
     store.graph.createNode('FRAME', pageId, {
       name: 'Card',
@@ -122,7 +125,8 @@ test('inner shadow', async () => {
 
 test('inner shadow with spread', async () => {
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
     store.graph.createNode('FRAME', pageId, {
       name: 'Card',
@@ -154,7 +158,8 @@ test('inner shadow with spread', async () => {
 
 test('drop shadow on ellipse', async () => {
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
     store.graph.createNode('ELLIPSE', pageId, {
       name: 'Circle',
@@ -185,7 +190,8 @@ test('drop shadow on ellipse', async () => {
 
 test('combined drop and inner shadow', async () => {
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
     store.graph.createNode('FRAME', pageId, {
       name: 'Card',
@@ -223,7 +229,8 @@ test('combined drop and inner shadow', async () => {
 
 test('text drop shadow on glyphs', async () => {
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
     store.graph.createNode('TEXT', pageId, {
       name: 'Shadow Text',
@@ -258,7 +265,8 @@ test('text drop shadow on glyphs', async () => {
 
 test('layer blur', async () => {
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
     store.graph.createNode('RECTANGLE', pageId, {
       name: 'Blurred',
@@ -290,7 +298,8 @@ test('layer blur', async () => {
 
 test('invisible effect has no visual impact', async () => {
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const pageId = store.state.currentPageId
     store.graph.createNode('FRAME', pageId, {
       name: 'Card',
diff --git a/tests/e2e/properties/panel.spec.ts b/tests/e2e/properties/panel.spec.ts
index 91eb92332..154bb64b7 100644
--- a/tests/e2e/properties/panel.spec.ts
+++ b/tests/e2e/properties/panel.spec.ts
@@ -96,7 +96,8 @@ test('variable bind badge appears on fill', async () => {
   await canvas.drawRect(200, 200, 80, 80)
 
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const col = store.graph.createCollection('Colors')
     const v = store.graph.createVariable('brand-red', 'COLOR', col.id, { r: 1, g: 0, b: 0, a: 1 })
     const id = [...store.state.selectedIds][0]
@@ -115,7 +116,8 @@ test('fill color can bind an existing variable', async () => {
   await canvas.drawRect(200, 200, 80, 80)
 
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const col = store.graph.createCollection('Colors')
     const variable = store.graph.createVariable('test-brand-red', 'COLOR', col.id, {
       r: 1,
@@ -143,7 +145,8 @@ test('fill color can bind an existing variable', async () => {
   await canvas.waitForRender()
   await expect(page.locator('[data-test-id="fill-unbind-variable"]')).toBeHidden()
   const boundVariableId = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     return id ? (store.getNode(id)?.boundVariables['fills/0/color'] ?? null) : null
   })
@@ -164,7 +167,8 @@ test('fill color can create and bind a variable', async () => {
 
   await expect(page.locator('[data-test-id="fill-unbind-variable"]')).toBeVisible()
   const boundVariable = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     if (!id) return null
     const node = store.getNode(id)
@@ -189,7 +193,8 @@ test('width can create, bind, and detach a number variable', async () => {
 
   await expect(page.locator('[data-test-id="layout-width-unbind-variable"]')).toBeVisible()
   const boundVariable = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     if (!id) return null
     const node = store.getNode(id)
@@ -207,7 +212,8 @@ test('width can create, bind, and detach a number variable', async () => {
 
   await expect(page.locator('[data-test-id="layout-width-unbind-variable"]')).toBeHidden()
   const directWidth = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     const node = id ? store.getNode(id) : null
     return node ? { width: node.width, binding: node.boundVariables.width ?? null } : null
diff --git a/tests/e2e/properties/visibility.spec.ts b/tests/e2e/properties/visibility.spec.ts
index 046a93664..49c68239d 100644
--- a/tests/e2e/properties/visibility.spec.ts
+++ b/tests/e2e/properties/visibility.spec.ts
@@ -20,7 +20,8 @@ test.afterAll(async () => {
 
 function getSelectedNode() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     if (!id) return null
     const n = store.graph.getNode(id)
diff --git a/tests/e2e/scene/cache.spec.ts b/tests/e2e/scene/cache.spec.ts
index 75dc14681..81a034d0c 100644
--- a/tests/e2e/scene/cache.spec.ts
+++ b/tests/e2e/scene/cache.spec.ts
@@ -12,7 +12,8 @@ test.describe('SkPicture scene caching', () => {
     await helper.waitForInit()
 
     await page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const pageId = store.state.currentPageId
 
       store.graph.createNode('FRAME', pageId, {
@@ -74,7 +75,8 @@ test.describe('SkPicture scene caching', () => {
     // We simulate this by calling invalidateScenePicture() to force the next
     // render to re-record, then verify hover on/off doesn't lose text.
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       // Simulate what loadFonts() does: invalidate the cached picture
       store.renderer!.invalidateScenePicture()
       store.requestRender()
@@ -83,7 +85,8 @@ test.describe('SkPicture scene caching', () => {
 
     // Extra render to stabilize the SkPicture cache
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       store.requestRender()
     })
     await helper.waitForRender()
@@ -93,7 +96,8 @@ test.describe('SkPicture scene caching', () => {
 
     // Hover frame → un-hover: replays the newly recorded picture
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const pg = store.graph.getNode(store.state.currentPageId)!
       const frame = pg.childIds.find((id: string) => store.graph.getNode(id)?.type === 'FRAME')
       store.setHoveredNode(frame ?? null)
@@ -101,7 +105,8 @@ test.describe('SkPicture scene caching', () => {
     await helper.waitForRender()
 
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       store.setHoveredNode(null)
     })
     await helper.waitForRender()
@@ -113,14 +118,16 @@ test.describe('SkPicture scene caching', () => {
   test('text survives hover on/off cycle', async () => {
     // 1. Baseline: no hover — this records the SkPicture cache
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       store.setHoveredNode(null)
       store.requestRender()
     })
     await helper.waitForRender()
     // Extra render cycle to ensure SkPicture cache is fully recorded
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       store.requestRender()
     })
     await helper.waitForRender()
@@ -128,7 +135,8 @@ test.describe('SkPicture scene caching', () => {
 
     // 2. Hover a frame — uses requestRepaint (only renderVersion, not sceneVersion)
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const page = store.graph.getNode(store.state.currentPageId)!
       const frame = page.childIds.find((id: string) => store.graph.getNode(id)?.type === 'FRAME')
       store.setHoveredNode(frame ?? null)
@@ -137,7 +145,8 @@ test.describe('SkPicture scene caching', () => {
 
     // 3. Hover off — should replay cached SkPicture (the critical transition)
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       store.setHoveredNode(null)
     })
     await helper.waitForRender()
@@ -151,7 +160,8 @@ test.describe('SkPicture scene caching', () => {
   test('text survives multiple hover cycles', async () => {
     // Rapid hover on/off using the real setHoveredNode path (requestRepaint)
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const page = store.graph.getNode(store.state.currentPageId)!
       const frame = page.childIds.find((id: string) => store.graph.getNode(id)?.type === 'FRAME')
 
@@ -168,7 +178,8 @@ test.describe('SkPicture scene caching', () => {
   test('text survives real mouse hover on/off', async () => {
     // Use actual mouse movement instead of programmatic setHoveredNode
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       store.setHoveredNode(null)
       store.requestRender()
     })
@@ -195,7 +206,8 @@ test.describe('SkPicture scene caching', () => {
   test('text survives scene change then hover cycle', async () => {
     // Mutate scene to invalidate picture cache
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const page = store.graph.getNode(store.state.currentPageId)!
       const frame = page.childIds.find((id: string) => store.graph.getNode(id)?.type === 'FRAME')
       if (frame) store.graph.updateNode(frame, { width: 310 })
@@ -205,7 +217,8 @@ test.describe('SkPicture scene caching', () => {
 
     // Hover on then off using real path
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const page = store.graph.getNode(store.state.currentPageId)!
       const frame = page.childIds.find((id: string) => store.graph.getNode(id)?.type === 'FRAME')
       store.setHoveredNode(frame ?? null)
@@ -213,7 +226,8 @@ test.describe('SkPicture scene caching', () => {
     await helper.waitForRender()
 
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       store.setHoveredNode(null)
     })
     await helper.waitForRender()
diff --git a/tests/e2e/snap/guides.spec.ts b/tests/e2e/snap/guides.spec.ts
index a04cf972e..07a9c3c8f 100644
--- a/tests/e2e/snap/guides.spec.ts
+++ b/tests/e2e/snap/guides.spec.ts
@@ -22,7 +22,8 @@ test.afterAll(async () => {
 async function createRects() {
   await canvas.clearCanvas()
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     store.createShape('RECTANGLE', 100, 100, 80, 80)
     const b = store.createShape('RECTANGLE', 300, 100, 80, 80)
     store.select([b])
diff --git a/tests/e2e/stroke-picker/basic.spec.ts b/tests/e2e/stroke-picker/basic.spec.ts
index 6ec05b96a..e11e0cecc 100644
--- a/tests/e2e/stroke-picker/basic.spec.ts
+++ b/tests/e2e/stroke-picker/basic.spec.ts
@@ -32,7 +32,8 @@ async function chooseFormat(page: Page, label: 'RGB' | 'HSL' | 'HSB' | 'OkHCL')
 
 async function getSelectedStroke(page: Page) {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     const node = store.graph.getNode(id)
     return node?.strokes?.[0] ?? null
@@ -87,7 +88,8 @@ test('stroke picker hsb saturation and brightness sliders update stroke color on
   await canvas.waitForInit()
 
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const nodes = Array.from(store.graph.nodes.values())
     const card =
       nodes.find((node) => node.name === 'Card' && node.type === 'COMPONENT') ??
diff --git a/tests/e2e/text/editing.spec.ts b/tests/e2e/text/editing.spec.ts
index 73cafb2f7..d3e0eae23 100644
--- a/tests/e2e/text/editing.spec.ts
+++ b/tests/e2e/text/editing.spec.ts
@@ -20,7 +20,8 @@ test.afterAll(async () => {
 
 function getSelectedNode() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     if (!id) return null
     const n = store.graph.getNode(id)
@@ -41,7 +42,8 @@ function getSelectedNode() {
 
 function getPageChildren() {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getChildren(store.state.currentPageId).map((n) => ({
       type: n.type,
       name: n.name,
@@ -100,7 +102,8 @@ test('creating text via store works', async () => {
   await canvas.waitForRender()
 
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = store.createShape('TEXT', 100, 300, 200, 30)
     store.graph.updateNode(id, { text: 'Hello World', fontSize: 24, fontFamily: 'Inter' })
     store.select([id])
@@ -140,7 +143,8 @@ test('Enter key opens text editing and selects all without erasing', async () =>
   await canvas.waitForRender()
 
   const textId = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = store.createShape('TEXT', 300, 300, 200, 30)
     store.graph.updateNode(id, { text: 'Keep this text' })
     store.select([id])
@@ -160,7 +164,8 @@ test('Enter key opens text editing and selects all without erasing', async () =>
   expect(editing).toBe(textId)
 
   const after = await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = store.state.editingTextId
     if (!id) return null
     return store.graph.getNode(id)?.text ?? null
diff --git a/tests/e2e/text/formatting.spec.ts b/tests/e2e/text/formatting.spec.ts
index 9fa974078..59aab4efa 100644
--- a/tests/e2e/text/formatting.spec.ts
+++ b/tests/e2e/text/formatting.spec.ts
@@ -16,7 +16,8 @@ test.beforeAll(async ({ browser }) => {
   await canvas.clearCanvas()
 
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     store.state.zoom = 1
     store.state.panX = 0
     store.state.panY = 0
@@ -52,7 +53,8 @@ test('bold button toggles fontWeight to 700 then back to 400', async () => {
 
   // ensure starting weight is 400 via undo-safe store method
   await page.evaluate(async (id: string) => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     store.updateNodeWithUndo(id, { fontWeight: 400 }, 'reset')
     store.state.sceneVersion++
     await new Promise(requestAnimationFrame)
diff --git a/tests/e2e/variables/dialog.spec.ts b/tests/e2e/variables/dialog.spec.ts
index 57bb646e5..cd9e7fed7 100644
--- a/tests/e2e/variables/dialog.spec.ts
+++ b/tests/e2e/variables/dialog.spec.ts
@@ -20,7 +20,8 @@ test.afterAll(async () => {
 
 async function createColorVariable(name: string) {
   return page.evaluate((varName: string) => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const existing = [...store.graph.variableCollections.values()]
     const col = existing.length > 0 ? existing[0] : store.graph.createCollection('Test Collection')
     const v = store.graph.createVariable(varName, 'COLOR', col.id, { r: 1, g: 0, b: 0, a: 1 })
@@ -43,7 +44,8 @@ test('variables dialog opens', async () => {
 
 test('search filters variable rows', async () => {
   await page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const col = [...store.graph.variableCollections.values()][0]
     store.graph.createVariable('beta-spacing', 'FLOAT', col.id, 8)
     store.state.sceneVersion++
diff --git a/tests/e2e/viewport/zoom-pan.spec.ts b/tests/e2e/viewport/zoom-pan.spec.ts
index 0860d0d7c..7b5a0ea79 100644
--- a/tests/e2e/viewport/zoom-pan.spec.ts
+++ b/tests/e2e/viewport/zoom-pan.spec.ts
@@ -14,7 +14,8 @@ test.describe('Zoom and pan', () => {
     await helper.waitForInit()
 
     await page.evaluate((count: number) => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const cols = Math.ceil(Math.sqrt(count))
       for (let i = 0; i < count; i++) {
         store.graph.createNode('RECTANGLE', store.state.currentPageId, {
@@ -38,7 +39,8 @@ test.describe('Zoom and pan', () => {
 
   test('wheel zoom updates viewport correctly', async () => {
     const before = await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       return { panX: store.state.panX, panY: store.state.panY, zoom: store.state.zoom }
     })
 
@@ -52,7 +54,8 @@ test.describe('Zoom and pan', () => {
     await helper.page.waitForTimeout(50)
 
     const after = await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       return { panX: store.state.panX, panY: store.state.panY, zoom: store.state.zoom }
     })
 
@@ -62,7 +65,8 @@ test.describe('Zoom and pan', () => {
 
   test('wheel pan updates viewport correctly', async () => {
     const before = await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       return { panX: store.state.panX, panY: store.state.panY }
     })
 
@@ -75,7 +79,8 @@ test.describe('Zoom and pan', () => {
     await helper.page.waitForTimeout(50)
 
     const after = await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       return { panX: store.state.panX, panY: store.state.panY }
     })
 
@@ -96,7 +101,8 @@ test.describe('Zoom and pan', () => {
     await helper.page.waitForTimeout(50)
 
     const state = await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       return { zoom: store.state.zoom }
     })
 
@@ -107,7 +113,8 @@ test.describe('Zoom and pan', () => {
 
   test('shallowReactive: selection replace triggers UI update', async () => {
     const result = await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const pageNode = store.graph.getNode(store.state.currentPageId)!
       const firstId = pageNode.childIds[0]
 
@@ -129,7 +136,8 @@ test.describe('Zoom and pan', () => {
   test('useRafFn loop picks up renderVersion changes', async () => {
     // Ensure clean state, wait for any pending renders
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       store.state.panX = 0
       store.state.panY = 0
       store.state.zoom = 1
@@ -142,7 +150,8 @@ test.describe('Zoom and pan', () => {
 
     // Change fill color — always visible
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const pageNode = store.graph.getNode(store.state.currentPageId)!
       const firstId = pageNode.childIds[0]
       store.graph.updateNode(firstId, {
@@ -158,7 +167,8 @@ test.describe('Zoom and pan', () => {
 
     // Restore
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const pageNode = store.graph.getNode(store.state.currentPageId)!
       const firstId = pageNode.childIds[0]
       store.graph.updateNode(firstId, {
@@ -175,7 +185,8 @@ test.describe('Zoom and pan', () => {
     const before = await helper.screenshotCanvas()
 
     await helper.page.evaluate(() => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
       const pageNode = store.graph.getNode(store.state.currentPageId)!
       store.select([pageNode.childIds[0]])
     })
@@ -196,7 +207,8 @@ test.describe('Zoom and pan', () => {
     const ITERATIONS = 500
 
     const results = await helper.page.evaluate((iterations: number) => {
-      const store = window.__OPEN_PENCIL_STORE__!
+      const store = window.__OPEN_PENCIL_STORE__
+      if (!store) throw new Error('OpenPencil store not initialized')
 
       // Reset viewport
       store.state.panX = 0
diff --git a/tests/engine/fonts/loading.test.ts b/tests/engine/fonts/loading.test.ts
index 268cab40b..f81dc8f29 100644
--- a/tests/engine/fonts/loading.test.ts
+++ b/tests/engine/fonts/loading.test.ts
@@ -16,6 +16,8 @@ import {
   fontFallbackManifest
 } from '@open-pencil/core'
 
+import { expectDefined } from '#tests/helpers/assert'
+
 function pageId(graph: SceneGraph) {
   return graph.getPages()[0].id
 }
@@ -491,12 +493,12 @@ describe('fetchBundledFont', () => {
   test('loads Inter-Regular.ttf from assets in headless', async () => {
     const buffer = await fontManager.fetchBundledFont('/Inter-Regular.ttf')
     expect(buffer).toBeInstanceOf(ArrayBuffer)
-    expect(buffer!.byteLength).toBeGreaterThan(100_000)
+    expect(expectDefined(buffer, 'Inter font buffer').byteLength).toBeGreaterThan(100_000)
   })
 
   test('returns valid TTF data', async () => {
     const buffer = await fontManager.fetchBundledFont('/Inter-Regular.ttf')
-    const view = new DataView(buffer!)
+    const view = new DataView(expectDefined(buffer, 'Inter font buffer'))
     // TrueType magic: 0x00010000
     expect(view.getUint32(0)).toBe(0x00010000)
   })
diff --git a/tests/engine/iconify.test.ts b/tests/engine/iconify.test.ts
index 47b3f945b..ac9c33f43 100644
--- a/tests/engine/iconify.test.ts
+++ b/tests/engine/iconify.test.ts
@@ -2,6 +2,8 @@ import { describe, expect, test, beforeAll } from 'bun:test'
 
 import { fetchIcon, fetchIcons, searchIcons, searchIconsBatch } from '@open-pencil/core'
 
+import { expectDefined } from '#tests/helpers/assert'
+
 let hasNetwork = true
 beforeAll(async () => {
   try {
@@ -129,7 +131,7 @@ describe('searchIconsBatch', () => {
   networkTest('searches multiple queries in parallel', async () => {
     const results = await searchIconsBatch(['heart', 'arrow'], { limit: 5 })
     expect(results.size).toBe(2)
-    expect(results.get('heart')!.icons.length).toBeGreaterThan(0)
-    expect(results.get('arrow')!.icons.length).toBeGreaterThan(0)
+    expect(expectDefined(results.get('heart'), 'heart results').icons.length).toBeGreaterThan(0)
+    expect(expectDefined(results.get('arrow'), 'arrow results').icons.length).toBeGreaterThan(0)
   })
 })
diff --git a/tests/engine/okhcl.test.ts b/tests/engine/okhcl.test.ts
index 54ae2e08f..2663d8b45 100644
--- a/tests/engine/okhcl.test.ts
+++ b/tests/engine/okhcl.test.ts
@@ -13,6 +13,8 @@ import {
   SceneGraph
 } from '@open-pencil/core'
 
+import { expectDefined } from '#tests/helpers/assert'
+
 describe('OkHCL metadata', () => {
   test('applies rgba rendering color while preserving fill metadata', () => {
     const graph = new SceneGraph()
@@ -79,12 +81,12 @@ describe('OkHCL metadata', () => {
     )
     const parsedFrame = [...parsed.getAllNodes()].find((node) => node.name === 'OKHCL frame')
 
-    expect(parsedFrame).toBeDefined()
-    expect(getFillOkHCL(parsedFrame!, 0)).toMatchObject({
+    const parsedOkhclFrame = expectDefined(parsedFrame, 'parsed OKHCL frame')
+    expect(getFillOkHCL(parsedOkhclFrame, 0)).toMatchObject({
       kind: 'fill',
       color: { h: 210, c: 0.1, l: 0.65, a: 1 }
     })
-    expect(getStrokeOkHCL(parsedFrame!, 0)).toMatchObject({
+    expect(getStrokeOkHCL(parsedOkhclFrame, 0)).toMatchObject({
       kind: 'stroke',
       color: { h: 320, c: 0.09, l: 0.55, a: 0.9 }
     })
diff --git a/tests/engine/snap.test.ts b/tests/engine/snap.test.ts
index 731b4e965..691e9fce7 100644
--- a/tests/engine/snap.test.ts
+++ b/tests/engine/snap.test.ts
@@ -2,6 +2,8 @@ import { describe, test, expect } from 'bun:test'
 
 import { computeSnap, computeSelectionBounds, type SceneNode } from '@open-pencil/core'
 
+import { expectDefined } from '#tests/helpers/assert'
+
 function node(overrides: Partial<SceneNode> & { id: string }): SceneNode {
   return { x: 0, y: 0, width: 100, height: 100, rotation: 0, ...overrides } as SceneNode
 }
@@ -25,9 +27,10 @@ describe('computeSelectionBounds', () => {
   })
 
   test('rotated node expands bbox', () => {
-    const bounds = computeSelectionBounds([
-      node({ id: 'a', x: 0, y: 0, width: 100, height: 0, rotation: 45 })
-    ])!
+    const bounds = expectDefined(
+      computeSelectionBounds([node({ id: 'a', x: 0, y: 0, width: 100, height: 0, rotation: 45 })]),
+      'rotated node bounds'
+    )
     expect(bounds.width).toBeGreaterThan(0)
     expect(bounds.height).toBeGreaterThan(0)
   })
diff --git a/tests/engine/tools/create.test.ts b/tests/engine/tools/create.test.ts
index 46fb1e53a..4b6634d0d 100644
--- a/tests/engine/tools/create.test.ts
+++ b/tests/engine/tools/create.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, test } from 'bun:test'
 
+import { expectDefined } from '#tests/helpers/assert'
 import { getTool, setupToolTest, type ToolResult } from '#tests/helpers/tools'
 
 describe('create_shape', () => {
@@ -17,7 +18,10 @@ describe('create_shape', () => {
     expect(result.name).toBe('Test Frame')
     expect(result.type).toBe('FRAME')
 
-    const node = figma.getNodeById(result.id)!
+    const node = expectDefined(
+      figma.getNodeById(expectDefined(result.id, 'created node id')),
+      'created node'
+    )
     expect(node.x).toBe(100)
     expect(node.y).toBe(200)
     expect(node.width).toBe(300)
@@ -44,7 +48,10 @@ describe('create_shape', () => {
       parent_id: parent.id
     }) as ToolResult
 
-    const parentNode = figma.getNodeById(parent.id)!
+    const parentNode = expectDefined(
+      figma.getNodeById(expectDefined(parent.id, 'created parent id')),
+      'created parent node'
+    )
     expect(parentNode.children.some((c) => c.id === child.id)).toBe(true)
   })
 })
diff --git a/tests/engine/visual-inner-shadow-counter.ts b/tests/engine/visual-inner-shadow-counter.ts
index 5d2c94d0d..1ec48ee35 100644
--- a/tests/engine/visual-inner-shadow-counter.ts
+++ b/tests/engine/visual-inner-shadow-counter.ts
@@ -7,6 +7,8 @@ import type { SceneNode } from '#core/scene-graph'
 import { SceneGraph } from '#core/scene-graph'
 import { fontManager } from '#core/text'
 
+import { expectDefined } from '#tests/helpers/assert'
+
 async function main() {
   const ck = await initCanvasKit()
 
@@ -55,7 +57,7 @@ async function main() {
 
   graph.createNode('TEXT', pageId, textProps)
 
-  const surface = ck.MakeSurface(width, height)!
+  const surface = expectDefined(ck.MakeSurface(width, height), 'CanvasKit surface')
   const canvas = surface.getCanvas()
   const renderer = new SkiaRenderer(ck, surface)
   renderer.fontProvider = fontProvider
diff --git a/tests/engine/visual-sdf-test-matrix.ts b/tests/engine/visual-sdf-test-matrix.ts
index 0b4fe24b4..f305ea43b 100644
--- a/tests/engine/visual-sdf-test-matrix.ts
+++ b/tests/engine/visual-sdf-test-matrix.ts
@@ -9,6 +9,8 @@ import type { SceneNode } from '#core/scene-graph'
 import { fontManager } from '#core/text'
 import type { Color, Vector } from '#core/types'
 
+import { expectDefined } from '#tests/helpers/assert'
+
 interface TestCase {
   text: string
   fontSize: number
@@ -202,7 +204,7 @@ async function main() {
 
     const surfW = Math.ceil(textProps.width) + 40
     const surfH = Math.ceil(textProps.height) + 40
-    const surface = ck.MakeSurface(surfW, surfH)!
+    const surface = expectDefined(ck.MakeSurface(surfW, surfH), 'CanvasKit surface')
     const renderer = new SkiaRenderer(ck, surface)
     renderer.fontProvider = fontProvider
     renderer.fontsLoaded = true
diff --git a/tests/engine/visual-verify-text-inner-shadow.ts b/tests/engine/visual-verify-text-inner-shadow.ts
index 7ad9ae61a..383b1644f 100644
--- a/tests/engine/visual-verify-text-inner-shadow.ts
+++ b/tests/engine/visual-verify-text-inner-shadow.ts
@@ -8,6 +8,8 @@ import { SceneGraph } from '#core/scene-graph'
 import type { SceneNode } from '#core/scene-graph'
 import { fontManager } from '#core/text'
 
+import { expectDefined } from '#tests/helpers/assert'
+
 async function main() {
   const ck = await initCanvasKit()
 
@@ -55,7 +57,7 @@ async function main() {
   const textNode = graph.createNode('TEXT', pageId, textProps)
   const nodeId = textNode.id
 
-  const surface = ck.MakeSurface(800, 300)!
+  const surface = expectDefined(ck.MakeSurface(800, 300), 'CanvasKit surface')
   const renderer = new SkiaRenderer(ck, surface)
   renderer.fontProvider = fontProvider
   renderer.fontsLoaded = true
diff --git a/tests/helpers/figma.ts b/tests/helpers/figma.ts
index fc17ecaf4..996844ae9 100644
--- a/tests/helpers/figma.ts
+++ b/tests/helpers/figma.ts
@@ -36,7 +36,9 @@ export class FigmaHelper {
   }
 
   private async canvasBounds() {
-    return this.canvas.boundingBox().then((b) => b!)
+    const bounds = await this.canvas.boundingBox()
+    if (!bounds) throw new Error('Figma canvas bounds unavailable')
+    return bounds
   }
 
   async waitForRender() {
diff --git a/tests/helpers/store.ts b/tests/helpers/store.ts
index 67c63e7d7..b256d7de0 100644
--- a/tests/helpers/store.ts
+++ b/tests/helpers/store.ts
@@ -1,12 +1,17 @@
 import type { Page } from '@playwright/test'
 
 export function getSelectedIds(page: Page) {
-  return page.evaluate(() => window.__OPEN_PENCIL_STORE__!.state.selectedIds.size)
+  return page.evaluate(() => {
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
+    return store.state.selectedIds.size
+  })
 }
 
 export function getPageChildren(page: Page) {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     return store.graph.getChildren(store.state.currentPageId).map((n) => ({
       id: n.id,
       type: n.type,
@@ -23,7 +28,8 @@ export function getPageChildren(page: Page) {
 
 export function getSelectedNode(page: Page) {
   return page.evaluate(() => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const id = [...store.state.selectedIds][0]
     if (!id) return null
     const n = store.graph.getNode(id)
@@ -53,7 +59,8 @@ export function getSelectedNode(page: Page) {
 
 export function getNodeById(page: Page, id: string) {
   return page.evaluate((nodeId: string) => {
-    const store = window.__OPEN_PENCIL_STORE__!
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
     const n = store.graph.getNode(nodeId)
     if (!n) return null
     return {
@@ -91,5 +98,9 @@ export function getNodeById(page: Page, id: string) {
 }
 
 export function getEditingTextId(page: Page) {
-  return page.evaluate(() => window.__OPEN_PENCIL_STORE__!.state.editingTextId)
+  return page.evaluate(() => {
+    const store = window.__OPEN_PENCIL_STORE__
+    if (!store) throw new Error('OpenPencil store not initialized')
+    return store.state.editingTextId
+  })
 }
diff --git a/tests/helpers/tools.ts b/tests/helpers/tools.ts
index 013fcfbd5..e31683e7c 100644
--- a/tests/helpers/tools.ts
+++ b/tests/helpers/tools.ts
@@ -5,7 +5,7 @@ export { ALL_TOOLS }
 import { expectDefined } from './assert'
 
 export interface ToolResult {
-  id: string
+  id?: string
   name?: string
   type?: string
   error?: string