diff --git a/src/renderer/components/extensions/skills/SkillEditorDialog.tsx b/src/renderer/components/extensions/skills/SkillEditorDialog.tsx
index 6ed48334..f5e625bf 100644
--- a/src/renderer/components/extensions/skills/SkillEditorDialog.tsx
+++ b/src/renderer/components/extensions/skills/SkillEditorDialog.tsx
@@ -35,6 +35,7 @@ import {
 import { toSuggestedSkillFolderName } from './skillFolderNameUtils';
 import { resolveSkillProjectPath } from './skillProjectUtils';
 import { SkillReviewDialog } from './SkillReviewDialog';
+import { validateSkillFolderName } from './skillValidationUtils';
 
 import type {
   SkillDetail,
@@ -305,6 +306,10 @@ export const SkillEditorDialog = ({
     if (!folderName.trim()) {
       return 'Choose a folder name for this skill.';
     }
+    const folderNameError = validateSkillFolderName(folderName);
+    if (folderNameError) {
+      return folderNameError;
+    }
     if (scope === 'project' && !effectiveProjectPath) {
       return 'Project skills need an active project.';
     }
diff --git a/src/renderer/components/extensions/skills/SkillImportDialog.tsx b/src/renderer/components/extensions/skills/SkillImportDialog.tsx
index eaf7a038..2dc73c4b 100644
--- a/src/renderer/components/extensions/skills/SkillImportDialog.tsx
+++ b/src/renderer/components/extensions/skills/SkillImportDialog.tsx
@@ -25,6 +25,7 @@ import { FileSearch, FolderOpen, X } from 'lucide-react';
 import { getSuggestedSkillFolderNameFromPath } from './skillFolderNameUtils';
 import { SkillReviewDialog } from './SkillReviewDialog';
 import { resolveSkillProjectPath } from './skillProjectUtils';
+import { validateSkillFolderName } from './skillValidationUtils';
 
 import type { SkillReviewPreview } from '@shared/types/extensions';
 
@@ -126,6 +127,13 @@ export const SkillImportDialog = ({
   }
 
   async function handleReview(): Promise<void> {
+    const folderNameError =
+      folderName.trim().length > 0 ? validateSkillFolderName(folderName) : null;
+    if (folderNameError) {
+      setMutationError(folderNameError);
+      return;
+    }
+
     setReviewLoading(true);
     setMutationError(null);
     try {
diff --git a/src/renderer/components/extensions/skills/skillValidationUtils.ts b/src/renderer/components/extensions/skills/skillValidationUtils.ts
new file mode 100644
index 00000000..6ec15845
--- /dev/null
+++ b/src/renderer/components/extensions/skills/skillValidationUtils.ts
@@ -0,0 +1,23 @@
+const MAX_SKILL_FOLDER_NAME_LENGTH = 255;
+const INVALID_SKILL_FOLDER_NAME_CHARS = /[\x00-\x1f/\\:*?"<>|]/u;
+
+export function validateSkillFolderName(value: string): string | null {
+  const trimmed = value.trim();
+  if (trimmed.length === 0) {
+    return 'Choose a folder name for this skill.';
+  }
+
+  if (trimmed.length > MAX_SKILL_FOLDER_NAME_LENGTH) {
+    return `Folder name must be ${MAX_SKILL_FOLDER_NAME_LENGTH} characters or fewer.`;
+  }
+
+  if (trimmed === '.' || trimmed === '..') {
+    return 'Pick a simpler folder name using letters, numbers, dots, dashes, or underscores.';
+  }
+
+  if (INVALID_SKILL_FOLDER_NAME_CHARS.test(trimmed)) {
+    return 'Pick a simpler folder name using letters, numbers, dots, dashes, or underscores.';
+  }
+
+  return null;
+}
diff --git a/test/renderer/components/extensions/skills/SkillEditorDialog.test.ts b/test/renderer/components/extensions/skills/SkillEditorDialog.test.ts
index 1f081ae3..fdf1f0a0 100644
--- a/test/renderer/components/extensions/skills/SkillEditorDialog.test.ts
+++ b/test/renderer/components/extensions/skills/SkillEditorDialog.test.ts
@@ -313,4 +313,51 @@ This file uses a freeform layout without generated sections.
       await Promise.resolve();
     });
   });
+
+  it('blocks review locally when the folder name is invalid', async () => {
+    const host = document.createElement('div');
+    document.body.appendChild(host);
+    const root = createRoot(host);
+
+    await act(async () => {
+      root.render(
+        React.createElement(SkillEditorDialog, {
+          open: true,
+          mode: 'create',
+          projectPath: '/tmp/project',
+          projectLabel: 'Project',
+          detail: null,
+          onClose: vi.fn(),
+          onSaved: vi.fn(),
+        })
+      );
+      await Promise.resolve();
+    });
+
+    const folderInput = host.querySelector('#skill-folder') as HTMLInputElement;
+    await act(async () => {
+      const setValue = Object.getOwnPropertyDescriptor(HTMLInputElement.prototype, 'value')?.set;
+      setValue?.call(folderInput, 'bad/name');
+      folderInput.dispatchEvent(new Event('input', { bubbles: true }));
+      await Promise.resolve();
+    });
+
+    const reviewButton = Array.from(host.querySelectorAll('button')).find((button) =>
+      button.textContent?.includes('Review And Create')
+    ) as HTMLButtonElement;
+    await act(async () => {
+      reviewButton.click();
+      await Promise.resolve();
+    });
+
+    expect(storeState.previewSkillUpsert).not.toHaveBeenCalled();
+    expect(host.textContent).toContain(
+      'Pick a simpler folder name using letters, numbers, dots, dashes, or underscores.'
+    );
+
+    await act(async () => {
+      root.unmount();
+      await Promise.resolve();
+    });
+  });
 });
diff --git a/test/renderer/components/extensions/skills/SkillImportDialog.test.ts b/test/renderer/components/extensions/skills/SkillImportDialog.test.ts
index b52cd66b..7229b258 100644
--- a/test/renderer/components/extensions/skills/SkillImportDialog.test.ts
+++ b/test/renderer/components/extensions/skills/SkillImportDialog.test.ts
@@ -378,4 +378,52 @@ describe('SkillImportDialog', () => {
       await Promise.resolve();
     });
   });
+
+  it('blocks import review locally when the folder name is invalid', async () => {
+    const host = document.createElement('div');
+    document.body.appendChild(host);
+    const root = createRoot(host);
+
+    await act(async () => {
+      root.render(
+        React.createElement(SkillImportDialog, {
+          open: true,
+          projectPath: null,
+          projectLabel: null,
+          onClose: vi.fn(),
+          onImported: vi.fn(),
+        })
+      );
+      await Promise.resolve();
+    });
+
+    const sourceInput = host.querySelector('#skill-import-source') as HTMLInputElement;
+    const folderInput = host.querySelector('#skill-import-folder') as HTMLInputElement;
+    await act(async () => {
+      const setValue = Object.getOwnPropertyDescriptor(HTMLInputElement.prototype, 'value')?.set;
+      setValue?.call(sourceInput, '/tmp/source-skill');
+      sourceInput.dispatchEvent(new Event('input', { bubbles: true }));
+      setValue?.call(folderInput, 'bad/name');
+      folderInput.dispatchEvent(new Event('input', { bubbles: true }));
+      await Promise.resolve();
+    });
+
+    const reviewButton = Array.from(host.querySelectorAll('button')).find((button) =>
+      button.textContent?.includes('Review And Import')
+    ) as HTMLButtonElement;
+    await act(async () => {
+      reviewButton.click();
+      await Promise.resolve();
+    });
+
+    expect(storeState.previewSkillImport).not.toHaveBeenCalled();
+    expect(host.textContent).toContain(
+      'Pick a simpler folder name using letters, numbers, dots, dashes, or underscores.'
+    );
+
+    await act(async () => {
+      root.unmount();
+      await Promise.resolve();
+    });
+  });
 });
diff --git a/test/renderer/components/extensions/skills/skillValidationUtils.test.ts b/test/renderer/components/extensions/skills/skillValidationUtils.test.ts
new file mode 100644
index 00000000..208b7d2c
--- /dev/null
+++ b/test/renderer/components/extensions/skills/skillValidationUtils.test.ts
@@ -0,0 +1,25 @@
+import { describe, expect, it } from 'vitest';
+
+import { validateSkillFolderName } from '../../../../../src/renderer/components/extensions/skills/skillValidationUtils';
+
+describe('skillValidationUtils', () => {
+  it('accepts normal folder names', () => {
+    expect(validateSkillFolderName('review-helper')).toBeNull();
+  });
+
+  it('rejects empty folder names', () => {
+    expect(validateSkillFolderName('   ')).toBe('Choose a folder name for this skill.');
+  });
+
+  it('rejects invalid filesystem characters', () => {
+    expect(validateSkillFolderName('bad/name')).toBe(
+      'Pick a simpler folder name using letters, numbers, dots, dashes, or underscores.'
+    );
+  });
+
+  it('rejects dot segments', () => {
+    expect(validateSkillFolderName('..')).toBe(
+      'Pick a simpler folder name using letters, numbers, dots, dashes, or underscores.'
+    );
+  });
+});