diff --git a/src/cli/actions/remoteAction.ts b/src/cli/actions/remoteAction.ts
index 689d1d8c6..7bd2d6a2a 100644
--- a/src/cli/actions/remoteAction.ts
+++ b/src/cli/actions/remoteAction.ts
@@ -21,6 +21,10 @@ export const runRemoteAction = async (
     throw new RepomixError('Git is not installed or not in the system PATH.');
   }
 
+  if (!isValidRemoteValue(repoUrl)) {
+    throw new RepomixError('Invalid repository URL or user/repo format');
+  }
+
   const spinner = new Spinner('Cloning repository...');
 
   const tempDirPath = await createTempDirectory();
@@ -111,3 +115,20 @@ export const copyOutputToCurrentDirectory = async (
     throw new RepomixError(`Failed to copy output file: ${(error as Error).message}`);
   }
 };
+
+export function isValidRemoteValue(remoteValue: string): boolean {
+  // Check the short form of the GitHub URL. e.g. yamadashy/repomix
+  const namePattern = '[a-zA-Z0-9](?:[a-zA-Z0-9._-]*[a-zA-Z0-9])?';
+  const shortFormRegex = new RegExp(`^${namePattern}/${namePattern}$`);
+  if (shortFormRegex.test(remoteValue)) {
+    return true;
+  }
+
+  // Check the direct form of the GitHub URL. e.g.  https://github.com/yamadashy/repomix or https://gist.github.com/yamadashy/1234567890abcdef
+  try {
+    new URL(remoteValue);
+    return true;
+  } catch (error) {
+    return false;
+  }
+}
diff --git a/src/core/file/gitCommand.ts b/src/core/file/gitCommand.ts
index 844abe223..8a5c795d6 100644
--- a/src/core/file/gitCommand.ts
+++ b/src/core/file/gitCommand.ts
@@ -2,26 +2,11 @@ import { execFile } from 'node:child_process';
 import fs from 'node:fs/promises';
 import path from 'node:path';
 import { promisify } from 'node:util';
+import { RepomixError } from '../../shared/errorHandle.js';
 import { logger } from '../../shared/logger.js';
 
 const execFileAsync = promisify(execFile);
 
-export function isValidRemoteUrl(url: string): boolean {
-  // Check the short form of the GitHub URL. e.g. yamadashy/repomix
-  const shortFormRegex = /^[a-zA-Z0-9_-]+\/[a-zA-Z0-9_-]+$/;
-  if (shortFormRegex.test(url)) {
-    return true;
-  }
-
-  // Check the direct form of the GitHub URL. e.g.  https://github.com/yamadashy/repomix or https://gist.github.com/yamadashy/1234567890abcdef
-  try {
-    new URL(url);
-    return true;
-  } catch (error) {
-    return false;
-  }
-}
-
 export const isGitInstalled = async (
   deps = {
     execFileAsync,
@@ -44,8 +29,11 @@ export const execGitShallowClone = async (
     execFileAsync,
   },
 ) => {
-  if (!isValidRemoteUrl(url)) {
-    throw new Error('Invalid repository URL or user/repo format');
+  // Check if the URL is valid
+  try {
+    new URL(url);
+  } catch (error) {
+    throw new RepomixError(`Invalid repository URL. Please provide a valid URL. url: ${url}`);
   }
 
   if (remoteBranch) {
diff --git a/src/index.ts b/src/index.ts
index 3fa09d676..1a4cf9866 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,10 +1,17 @@
-export type { RepomixConfigFile as RepomixConfig } from './config/configSchema.js';
-
-export { pack } from './core/packager.js';
-
+// CLI
 export { run as cli } from './cli/cliRun.js';
 export type { CliOptions } from './cli/cliRun.js';
 
+// Config
+export type { RepomixConfigFile as RepomixConfig } from './config/configSchema.js';
+
+// Init action
 export { runInitAction } from './cli/actions/initAction.js';
-export { runRemoteAction } from './cli/actions/remoteAction.js';
+
+// Default action
 export { runDefaultAction } from './cli/actions/defaultAction.js';
+export { pack } from './core/packager.js';
+
+// Remote action
+export { runRemoteAction } from './cli/actions/remoteAction.js';
+export { isValidRemoteValue } from './cli/actions/remoteAction.js';
diff --git a/tests/cli/actions/remoteAction.test.ts b/tests/cli/actions/remoteAction.test.ts
index 8e33aee25..2cc5d68ac 100644
--- a/tests/cli/actions/remoteAction.test.ts
+++ b/tests/cli/actions/remoteAction.test.ts
@@ -1,7 +1,12 @@
 import * as fs from 'node:fs/promises';
 import path from 'node:path';
 import { beforeEach, describe, expect, test, vi } from 'vitest';
-import { copyOutputToCurrentDirectory, formatGitUrl, runRemoteAction } from '../../../src/cli/actions/remoteAction.js';
+import {
+  copyOutputToCurrentDirectory,
+  formatGitUrl,
+  isValidRemoteValue,
+  runRemoteAction,
+} from '../../../src/cli/actions/remoteAction.js';
 
 vi.mock('node:fs/promises', async (importOriginal) => {
   const actual = await importOriginal<typeof import('node:fs/promises')>();
@@ -76,4 +81,76 @@ describe('remoteAction functions', () => {
       );
     });
   });
+
+  describe('isValidRemoteValue', () => {
+    describe('GitHub shorthand format (user/repo)', () => {
+      test('should accept valid repository names', () => {
+        // Test cases for valid repository names with various allowed characters
+        const validUrls = [
+          'user/repo',
+          'user123/repo-name',
+          'org-name/repo_name',
+          'user.name/repo.test',
+          'user_name/repo_test',
+          'a/b', // Minimum length case
+          'user-name123/repo-test123.sub_123', // Complex case
+        ];
+
+        for (const url of validUrls) {
+          expect(isValidRemoteValue(url), `URL should be valid: ${url}`).toBe(true);
+        }
+      });
+
+      test('should reject invalid repository names', () => {
+        // Test cases for invalid patterns and disallowed characters
+        const invalidUrls = [
+          '', // Empty string
+          'user', // Missing slash
+          '/repo', // Missing username
+          'user/', // Missing repository name
+          '-user/repo', // Starts with hyphen
+          'user/-repo', // Repository starts with hyphen
+          'user./repo', // Username ends with dot
+          'user/repo.', // Repository ends with dot
+          'user/repo#branch', // Contains invalid character
+          'user/repo/extra', // Extra path segment
+          'us!er/repo', // Contains invalid character
+          'user/re*po', // Contains invalid character
+          'user//repo', // Double slash
+          '.user/repo', // Starts with dot
+          'user/.repo', // Repository starts with dot
+        ];
+
+        for (const url of invalidUrls) {
+          expect(isValidRemoteValue(url), `URL should be invalid: ${url}`).toBe(false);
+        }
+      });
+    });
+
+    describe('Full URL format', () => {
+      test('should accept valid URLs', () => {
+        // Test cases for standard URL formats
+        const validUrls = [
+          'https://example.com',
+          'http://localhost',
+          'https://github.com/user/repo',
+          'https://gitlab.com/user/repo',
+          'https://domain.com/path/to/something',
+        ];
+
+        for (const url of validUrls) {
+          expect(isValidRemoteValue(url), `URL should be valid: ${url}`).toBe(true);
+        }
+      });
+
+      test('should reject invalid URLs', () => {
+        // Test cases for malformed URLs
+        const invalidUrls = ['not-a-url', 'http://', 'https://', '://no-protocol.com', 'http://[invalid]'];
+
+        for (const url of invalidUrls) {
+          expect(isValidRemoteValue(url), `URL should be invalid: ${url}`).toBe(false);
+        }
+      });
+    });
+  });
 });