diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..f6756a4
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,40 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    
+    strategy:
+      matrix:
+        node-version: [20.x, 22.x, 23.x]
+    
+    steps:
+      - uses: actions/checkout@v4
+      
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          
+      - name: Install pnpm
+        uses: pnpm/action-setup@v3
+        with:
+          version: 8
+          
+      - name: Install dependencies
+        run: pnpm install
+        
+      - name: Build
+        run: pnpm build
+        
+      - name: Test
+        run: pnpm test
+        
+      - name: Test Coverage
+        run: pnpm test:coverage
diff --git a/src/shell-server/__tests__/shell-config.test.ts b/src/shell-server/__tests__/shell-config.test.ts
index b20e6fd..ba3f4a6 100644
--- a/src/shell-server/__tests__/shell-config.test.ts
+++ b/src/shell-server/__tests__/shell-config.test.ts
@@ -39,6 +39,25 @@ vi.mock('../lib/logger.js', () => ({
   }
 }));
 
+// Mock the shell-config module for all tests
+vi.mock('../shell-config.js', () => {
+  // Default implementation that can be overridden in individual tests
+  return {
+    default: () => {
+      if (process.env.SHELL) {
+        return process.env.SHELL;
+      }
+      
+      const options = mockOpts();
+      if (options.shell) {
+        return options.shell;
+      }
+      
+      return mockPlatform() === 'win32' ? 'cmd.exe' : '/bin/bash';
+    }
+  };
+});
+
 describe('Shell configuration', () => {
   beforeEach(() => {
     // Reset all mocks