diff --git a/docs/installation.md b/docs/installation.md
index 71cf1a0..e81c8ac 100644
--- a/docs/installation.md
+++ b/docs/installation.md
@@ -21,9 +21,10 @@ invokes thoth-mem's public setup command. Once installed, SDD phases load local
 contracts and provider guidance without consuming either CLI or the network.
 
 Nested package installation is non-interactive: the CLI confirms both `npx`
-package acquisition and the `skills` operation explicitly. On Windows it routes
-npm's `npx.cmd` shim and Codex's `codex.cmd` shim through `cmd.exe`; Linux and
-macOS execute those commands directly.
+package acquisition and the `skills` operation explicitly. On Windows it passes
+each complete `npx` command as one `cmd.exe /c` payload and invokes the
+extension-neutral `codex` command, supporting both standalone `codex.exe` and
+npm's `codex.cmd` shim. Linux and macOS execute those commands directly.
 
 ## Supported flow
 
diff --git a/src/cli/codex-plugin-install.test.ts b/src/cli/codex-plugin-install.test.ts
index ed239d8..a94a3db 100644
--- a/src/cli/codex-plugin-install.test.ts
+++ b/src/cli/codex-plugin-install.test.ts
@@ -65,7 +65,7 @@ function executor(state: ManagerState): CodexCommandExecutor {
 }
 
 describe('Codex native plugin installation', () => {
-  test('routes the Codex npm shim through cmd.exe on Windows', () => {
+  test('routes Codex through an extension-neutral command on Windows', () => {
     const invocation = getCodexCommand(
       ['plugin', 'list', '--available', '--json'],
       { platform: 'win32', commandShell: 'C:\\Windows\\System32\\cmd.exe' },
@@ -77,7 +77,7 @@ describe('Codex native plugin installation', () => {
         '/d',
         '/s',
         '/c',
-        'codex.cmd',
+        'codex',
         'plugin',
         'list',
         '--available',
diff --git a/src/cli/codex-plugin-install.ts b/src/cli/codex-plugin-install.ts
index b89642d..c2b4a97 100644
--- a/src/cli/codex-plugin-install.ts
+++ b/src/cli/codex-plugin-install.ts
@@ -84,7 +84,7 @@ export function getCodexCommand(
 
   return {
     command: options.commandShell ?? process.env.ComSpec ?? 'cmd.exe',
-    args: ['/d', '/s', '/c', 'codex.cmd', ...args],
+    args: ['/d', '/s', '/c', 'codex', ...args],
   };
 }
 
diff --git a/src/cli/npx-command.test.ts b/src/cli/npx-command.test.ts
new file mode 100644
index 0000000..cac0374
--- /dev/null
+++ b/src/cli/npx-command.test.ts
@@ -0,0 +1,31 @@
+import { describe, expect, test } from 'vitest';
+import { getNpxCommand } from './npx-command';
+
+describe('npx command invocation', () => {
+  test('passes the complete npx command string to cmd.exe on Windows', () => {
+    const commandShell = 'C:\\Windows\\System32\\cmd.exe';
+
+    expect(
+      getNpxCommand(
+        [
+          '-y',
+          'thoth-mem@latest',
+          'setup',
+          'codex',
+          '--scope',
+          'global',
+          '--json',
+        ],
+        { platform: 'win32', commandShell },
+      ),
+    ).toEqual({
+      command: commandShell,
+      args: [
+        '/d',
+        '/s',
+        '/c',
+        'npx -y thoth-mem@latest setup codex --scope global --json',
+      ],
+    });
+  });
+});
diff --git a/src/cli/npx-command.ts b/src/cli/npx-command.ts
index 2c52f0a..1694c38 100644
--- a/src/cli/npx-command.ts
+++ b/src/cli/npx-command.ts
@@ -18,6 +18,6 @@ export function getNpxCommand(
 
   return {
     command: options.commandShell ?? process.env.ComSpec ?? 'cmd.exe',
-    args: ['/d', '/s', '/c', 'npx.cmd', ...args],
+    args: ['/d', '/s', '/c', ['npx', ...args].join(' ')],
   };
 }
diff --git a/src/cli/skills.test.ts b/src/cli/skills.test.ts
index aaa0138..7fab147 100644
--- a/src/cli/skills.test.ts
+++ b/src/cli/skills.test.ts
@@ -154,7 +154,7 @@ describe('required skill install helper', () => {
     );
   });
 
-  test('routes the npx package shim through cmd.exe on Windows', () => {
+  test('routes the complete npx command through cmd.exe on Windows', () => {
     const homeDir = mkdtempSync(join(tmpdir(), 'thoth-skill-home-'));
     const commandShell = 'C:\\Windows\\System32\\cmd.exe';
     vi.mocked(spawnSync).mockReturnValueOnce({
@@ -173,17 +173,7 @@ describe('required skill install helper', () => {
         '/d',
         '/s',
         '/c',
-        'npx.cmd',
-        '--yes',
-        'skills',
-        'add',
-        testSkill.repo,
-        '--skill',
-        testSkill.skillName,
-        '--global',
-        '--agent',
-        'codex',
-        '--yes',
+        'npx --yes skills add https://example.test/simplify --skill simplify --global --agent codex --yes',
       ],
     };
 
diff --git a/src/cli/thoth-mem-install.test.ts b/src/cli/thoth-mem-install.test.ts
index da41078..1fdf53b 100644
--- a/src/cli/thoth-mem-install.test.ts
+++ b/src/cli/thoth-mem-install.test.ts
@@ -83,7 +83,7 @@ describe('thoth-mem setup adapter', () => {
     expect(applied.args).not.toContain('--force');
   });
 
-  test('routes the provider npx package shim through cmd.exe on Windows', () => {
+  test('routes the complete provider command through cmd.exe on Windows', () => {
     const commandShell = 'C:\\Windows\\System32\\cmd.exe';
 
     expect(
@@ -97,14 +97,7 @@ describe('thoth-mem setup adapter', () => {
         '/d',
         '/s',
         '/c',
-        'npx.cmd',
-        '-y',
-        'thoth-mem@latest',
-        'setup',
-        'codex',
-        '--scope',
-        'global',
-        '--json',
+        'npx -y thoth-mem@latest setup codex --scope global --json',
       ],
     });
   });