diff --git a/apps/web/src/components/dialogs/AiAssistantDialog.tsx b/apps/web/src/components/dialogs/AiAssistantDialog.tsx
index 3b233887..e0725718 100644
--- a/apps/web/src/components/dialogs/AiAssistantDialog.tsx
+++ b/apps/web/src/components/dialogs/AiAssistantDialog.tsx
@@ -401,7 +401,7 @@ export const AiAssistantDialog = ({
         <section
           ref={assignPanelRef}
           aria-label={t("aiAssistant.title")}
-          className="fixed z-[70] max-h-[70dvh] w-[min(36rem,calc(100vw-1.5rem))] overflow-y-auto rounded-xl border border-slate-200 bg-white p-4 shadow-2xl ring-1 ring-slate-950/5"
+          className="fixed z-[70] flex max-h-[70dvh] w-[min(36rem,calc(100vw-1.5rem))] flex-col overflow-hidden rounded-xl border border-slate-200 bg-white p-4 shadow-2xl ring-1 ring-slate-950/5"
           role="dialog"
           style={panelStyle}
           onKeyDown={(event) => {
@@ -412,7 +412,7 @@ export const AiAssistantDialog = ({
             }
           }}
         >
-          <div className="mb-3 flex items-center justify-between gap-3">
+          <div className="mb-3 flex shrink-0 items-center justify-between gap-3">
             <div className="flex min-w-0 items-center gap-2">
               <Sparkles className="h-5 w-5 shrink-0 text-emerald-600" />
               <span className="truncate text-sm font-semibold text-slate-950">{t("aiAssistant.title")}</span>
@@ -424,7 +424,8 @@ export const AiAssistantDialog = ({
               <X className="h-4 w-4" />
             </Button>
           </div>
-          <div className="grid gap-4">
+          <div className="min-h-0 flex-1 overflow-y-auto pr-1">
+            <div className="grid gap-4">
             {hasSelection ? (
               <p className="max-h-12 overflow-hidden whitespace-pre-wrap border-l-2 border-emerald-200 pl-3 text-xs leading-5 text-slate-500">
                 {selectionMarkdown}
@@ -474,7 +475,7 @@ export const AiAssistantDialog = ({
                     </SelectGroup>
                   </SelectContent>
                 </Select>
-                <div className="grid min-w-0 grid-cols-2 gap-2 sm:grid-cols-[auto_auto]">
+                <div className="grid min-w-0 grid-cols-2 gap-2 sm:grid-cols-[8rem_7rem]">
                   <Button
                     type="button"
                     variant={!selectedPromptId && action === "custom" ? "solid" : "outline"}
@@ -671,9 +672,10 @@ export const AiAssistantDialog = ({
                 </div>
               </div>
             ) : null}
+            </div>
           </div>
           {output ? (
-            <div className="mt-4 flex flex-wrap justify-between gap-2">
+            <div className="mt-3 flex shrink-0 flex-wrap justify-between gap-2 border-t border-slate-200 pt-3" data-ai-assistant-actions>
               <div className="flex flex-wrap gap-2">
                 <Button type="button" variant="outline" disabled={isGenerating} onClick={() => void copy()}>{copied ? <Check className="h-4 w-4" /> : <Copy className="h-4 w-4" />}{t(copied ? "aiAssistant.copied" : "aiAssistant.copy")}</Button>
                 <Button type="button" variant="outline" disabled={isGenerating} onClick={() => { setOutput(""); setError(null); }}><Trash2 className="h-4 w-4" />{t("aiAssistant.discard")}</Button>
diff --git a/tests/e2e/ai-custom-prompts.spec.ts b/tests/e2e/ai-custom-prompts.spec.ts
index da815cf2..cc476b37 100644
--- a/tests/e2e/ai-custom-prompts.spec.ts
+++ b/tests/e2e/ai-custom-prompts.spec.ts
@@ -182,7 +182,21 @@ test.describe("AI custom prompts", () => {
     const assistant = page.getByRole("dialog", { name: "AI 笔记助手" });
     await expect(assistant).toBeVisible();
     const customInstructionButton = assistant.getByRole("button", { name: "自定义指令", exact: true });
+    const actionSelect = assistant.getByRole("combobox", { name: "处理方式" });
+    const generateButton = assistant.getByRole("button", { name: "生成", exact: true });
     await expect(customInstructionButton).toBeVisible();
+    const [actionSelectBox, customInstructionBox, generateBox] = await Promise.all([
+      actionSelect.boundingBox(),
+      customInstructionButton.boundingBox(),
+      generateButton.boundingBox(),
+    ]);
+    expect(actionSelectBox).not.toBeNull();
+    expect(customInstructionBox).not.toBeNull();
+    expect(generateBox).not.toBeNull();
+    expect(customInstructionBox!.width).toBeGreaterThanOrEqual(120);
+    expect(generateBox!.width).toBeGreaterThanOrEqual(104);
+    expect(actionSelectBox!.width / customInstructionBox!.width).toBeLessThan(2.5);
+    expect(customInstructionBox!.width / generateBox!.width).toBeLessThan(1.25);
     const customInstructionLineCount = await customInstructionButton.evaluate((element) => {
       const textNode = Array.from(element.childNodes)
         .find((node) => node.nodeType === Node.TEXT_NODE && node.textContent?.trim());
@@ -409,6 +423,7 @@ test.describe("AI custom prompts", () => {
   });
 
   test("inserts generated content at the caret captured when AI opens", async ({ page }) => {
+    await page.setViewportSize({ width: 1180, height: 720 });
     const memo = await createMemo(
       page,
       `e2e-ai-caret-insert-${Date.now()}`,
@@ -428,7 +443,23 @@ test.describe("AI custom prompts", () => {
     const dialog = page.getByRole("dialog", { name: "AI 笔记助手" });
     await dialog.getByRole("button", { name: "生成", exact: true }).click();
     await expect(dialog.getByText("AI 插入段落", { exact: true })).toBeVisible();
-    await dialog.getByRole("button", { name: "追加到笔记", exact: true }).click();
+    const copyButton = dialog.getByRole("button", { name: "复制结果", exact: true });
+    const appendButton = dialog.getByRole("button", { name: "追加到笔记", exact: true });
+    await expect(copyButton).toBeVisible();
+    await expect(appendButton).toBeVisible();
+    const [dialogBox, copyButtonBox, appendButtonBox] = await Promise.all([
+      dialog.boundingBox(),
+      copyButton.boundingBox(),
+      appendButton.boundingBox(),
+    ]);
+    expect(dialogBox).not.toBeNull();
+    expect(copyButtonBox).not.toBeNull();
+    expect(appendButtonBox).not.toBeNull();
+    expect(copyButtonBox!.y).toBeGreaterThanOrEqual(dialogBox!.y);
+    expect(copyButtonBox!.y + copyButtonBox!.height).toBeLessThanOrEqual(dialogBox!.y + dialogBox!.height);
+    expect(appendButtonBox!.y).toBeGreaterThanOrEqual(dialogBox!.y);
+    expect(appendButtonBox!.y + appendButtonBox!.height).toBeLessThanOrEqual(dialogBox!.y + dialogBox!.height);
+    await appendButton.click();
     await expect(dialog).toBeHidden();
     await expect.poll(() => editor.locator(":scope > p").allTextContents()).toEqual([
       "第一段",