diff --git a/gitnexus/src/cli/setup.ts b/gitnexus/src/cli/setup.ts
index 3e7cbad8f..fe9d86f52 100644
--- a/gitnexus/src/cli/setup.ts
+++ b/gitnexus/src/cli/setup.ts
@@ -61,11 +61,13 @@ function resolveGitnexusBin(): string | null {
       .filter(Boolean);
 
     if (isWin) {
-      // On Windows, `where` returns multiple entries (e.g. the POSIX shell
-      // script AND the .cmd/.bat wrapper). Prefer the wrapper because
-      // child_process.spawn() cannot execute a shell script directly.
+      // On Windows, npm global installs can surface multiple launchers for the
+      // same package (e.g. a POSIX shell shim plus .cmd/.bat wrappers). Claude
+      // and the other MCP hosts need a directly spawnable command path, so only
+      // accept the Windows wrapper. If it is missing, fall back to the slower
+      // npx entry instead of persisting a non-spawnable shim path.
       const cmdLine = lines.find((l) => /\.(cmd|bat)$/i.test(l));
-      return cmdLine || lines[0] || null;
+      return cmdLine || null;
     }
 
     return lines[0] || null;
diff --git a/gitnexus/test/unit/setup-codex.test.ts b/gitnexus/test/unit/setup-codex.test.ts
index 95761bed0..5951c9325 100644
--- a/gitnexus/test/unit/setup-codex.test.ts
+++ b/gitnexus/test/unit/setup-codex.test.ts
@@ -15,8 +15,13 @@ const execFileMock = vi.fn((...args: any[]) => {
   }
 });
 
+const execFileSyncMock = vi.fn(() => {
+  throw new Error('not found');
+});
+
 vi.mock('child_process', () => ({
   execFile: execFileMock,
+  execFileSync: execFileSyncMock,
 }));
 
 describe('setupCommand codex execution', () => {
@@ -74,6 +79,21 @@ describe('setupCommand codex execution', () => {
     );
   });
 
+  it('uses Windows npx fallback arguments when where returns only a non-wrapper shim', async () => {
+    execFileSyncMock.mockReturnValueOnce('C:\\Users\\dev\\AppData\\Roaming\\npm\\gitnexus\n');
+
+    const { setupCommand } = await import('../../src/cli/setup.js');
+
+    await setupCommand();
+
+    expect(execFileMock).toHaveBeenCalledWith(
+      'codex',
+      ['mcp', 'add', 'gitnexus', '--', 'cmd', '/c', 'npx', '-y', NPX_REF, 'mcp'],
+      { shell: true },
+      expect.any(Function),
+    );
+  });
+
   it('invokes codex mcp add without shell on non-Windows and does not write fallback config', async () => {
     setPlatform('darwin');
 
diff --git a/gitnexus/test/unit/setup-jsonc.test.ts b/gitnexus/test/unit/setup-jsonc.test.ts
index e31955950..f4f44c618 100644
--- a/gitnexus/test/unit/setup-jsonc.test.ts
+++ b/gitnexus/test/unit/setup-jsonc.test.ts
@@ -241,6 +241,50 @@ describe('setupOpenCode — JSONC preservation', () => {
     });
   });
 
+  it('uses Windows npx fallback when where returns only a non-wrapper shim', async () => {
+    setPlatform('win32');
+    execFileSyncMock.mockReturnValueOnce('C:\\Users\\dev\\AppData\\Roaming\\npm\\gitnexus\n');
+
+    const jsonc = `{
+  "model": "test",
+  "mcp": {}
+}`;
+    await fs.writeFile(opencodeJsonPath(), jsonc, 'utf-8');
+
+    const { setupCommand } = await import('../../src/cli/setup.js');
+    await setupCommand();
+
+    const raw = await fs.readFile(opencodeJsonPath(), 'utf-8');
+    const config = parseJsonc(raw);
+
+    expect(config.mcp.gitnexus).toEqual({
+      type: 'local',
+      command: ['cmd', '/c', 'npx', '-y', NPX_REF, 'mcp'],
+    });
+  });
+
+  it('uses Windows npx fallback when where returns only a .ps1 path', async () => {
+    setPlatform('win32');
+    execFileSyncMock.mockReturnValueOnce('C:\\Users\\dev\\AppData\\Roaming\\npm\\gitnexus.ps1\n');
+
+    const jsonc = `{
+  "model": "test",
+  "mcp": {}
+}`;
+    await fs.writeFile(opencodeJsonPath(), jsonc, 'utf-8');
+
+    const { setupCommand } = await import('../../src/cli/setup.js');
+    await setupCommand();
+
+    const raw = await fs.readFile(opencodeJsonPath(), 'utf-8');
+    const config = parseJsonc(raw);
+
+    expect(config.mcp.gitnexus).toEqual({
+      type: 'local',
+      command: ['cmd', '/c', 'npx', '-y', NPX_REF, 'mcp'],
+    });
+  });
+
   it('preserves tab indentation in existing file', async () => {
     const tabbed = `{\n\t"model": "test"\n}`;
     await fs.writeFile(opencodeJsonPath(), tabbed, 'utf-8');
@@ -360,6 +404,22 @@ describe('setupCursor — JSONC preservation', () => {
     const raw = await fs.readFile(mcpPath(), 'utf-8');
     expect(raw).toBe(corrupt);
   });
+
+  it('uses Windows npx fallback when where returns only a non-wrapper shim', async () => {
+    setPlatform('win32');
+    execFileSyncMock.mockReturnValueOnce('C:\\Users\\dev\\AppData\\Roaming\\npm\\gitnexus\n');
+
+    const { setupCommand } = await import('../../src/cli/setup.js');
+    await setupCommand();
+
+    const raw = await fs.readFile(mcpPath(), 'utf-8');
+    const config = parseJsonc(raw);
+
+    expect(config.mcpServers.gitnexus).toEqual({
+      command: 'cmd',
+      args: ['/c', 'npx', '-y', NPX_REF, 'mcp'],
+    });
+  });
 });
 
 describe('setupClaudeCode — JSONC preservation', () => {
diff --git a/gitnexus/test/unit/setup.test.ts b/gitnexus/test/unit/setup.test.ts
index bdf1cd1fd..ee43d97d7 100644
--- a/gitnexus/test/unit/setup.test.ts
+++ b/gitnexus/test/unit/setup.test.ts
@@ -282,9 +282,9 @@ describe('setupClaudeCode', () => {
     ).resolves.toBeUndefined();
   });
 
-  it('falls back to first line on Windows when no .cmd/.bat wrapper found', async () => {
+  it('falls back to npx on Windows when no .cmd/.bat wrapper is found', async () => {
     setPlatform('win32');
-    // Edge case: where returns only the POSIX script (no .cmd wrapper)
+    // Edge case: where returns only a non-spawnable shim (no .cmd wrapper)
     execFileSyncMock.mockReturnValueOnce('C:\\Users\\dev\\AppData\\Roaming\\npm\\gitnexus\n');
 
     const { setupCommand } = await import('../../src/cli/setup.js');
@@ -294,8 +294,24 @@ describe('setupClaudeCode', () => {
     const config = JSON.parse(raw);
 
     expect(config.mcpServers.gitnexus).toEqual({
-      command: 'C:\\Users\\dev\\AppData\\Roaming\\npm\\gitnexus',
-      args: ['mcp'],
+      command: 'cmd',
+      args: ['/c', 'npx', '-y', NPX_REF, 'mcp'],
+    });
+  });
+
+  it('falls back to npx on Windows when where returns only a .ps1 path', async () => {
+    setPlatform('win32');
+    execFileSyncMock.mockReturnValueOnce('C:\\Users\\dev\\AppData\\Roaming\\npm\\gitnexus.ps1\n');
+
+    const { setupCommand } = await import('../../src/cli/setup.js');
+    await setupCommand();
+
+    const raw = await fs.readFile(path.join(tempHome, '.claude.json'), 'utf-8');
+    const config = JSON.parse(raw);
+
+    expect(config.mcpServers.gitnexus).toEqual({
+      command: 'cmd',
+      args: ['/c', 'npx', '-y', NPX_REF, 'mcp'],
     });
   });
 });