@@ -1,7 +1,5 @@
 import process from 'node:process'
 import { defineCommand } from 'citty'
-
-import { isTest } from 'std-env'
 import { resolveRootDir } from '../utils/paths'
 
 import { dotEnvArgs, envNameArgs, logLevelArgs, rootDirArgs } from './_shared'
@@ -24,13 +22,12 @@ export default defineCommand({
     },
   },
   async run(ctx) {
-    if (!process.send && !isTest) {
-      console.warn('`nuxt _dev` is an internal command and should not be used directly. Please use `nuxt dev` instead.')
-    }
-
     const cwd = resolveRootDir(ctx.args)
+    const listenOverrides = process.env._PORT
+      ? { port: process.env._PORT, hostname: '127.0.0.1', showURL: false } as const
+      : undefined
 
     const { initialize } = await import('../dev')
-    await initialize({ cwd, args: ctx.args }, ctx)
+    await initialize({ cwd, args: ctx.args }, { data: ctx.data, listenOverrides })
   },
 })
@@ -438,15 +438,6 @@ function parsePositiveInteger(value: string | undefined): number | undefined {
 }
 
 function resolveListenOverrides(args: ParsedArgs<ArgsT>): DevListenOverrides {
-  // _PORT is used by `@nuxt/test-utils` to launch the dev server on a specific port
-  if (process.env._PORT) {
-    return {
-      port: process.env._PORT || 0,
-      hostname: '127.0.0.1',
-      showURL: false,
-    } as const
-  }
-
   const httpsOptions: HTTPSOptions = {
     cert: args['https.cert']
       || args.sslCert
 
@@ -10,12 +10,6 @@ const bins = {
   'nuxi': join(fileURLToPath(new URL('../../../nuxi', import.meta.url)), 'bin/nuxi.mjs'),
 }
 
-/**
- * Commands that must stay dispatchable but are kept out of help output.
- *
- * `_dev` is spawned by `@nuxt/test-utils` (see its `src/e2e/server.ts`) and
- * `start` is a long-standing alias of `preview`.
- */
 const hiddenCommands = ['_dev', 'start'] as const
 
 function run(bin: string, args: string[]) {
 
@@ -0,0 +1,43 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+
+const { initialize } = vi.hoisted(() => ({
+  initialize: vi.fn(() => Promise.resolve()),
+}))
+
+vi.mock('../../../src/dev', () => ({ initialize }))
+
+describe('nuxt _dev command', () => {
+  afterEach(() => {
+    vi.unstubAllEnvs()
+    initialize.mockClear()
+  })
+
+  it('should initialize the requested root directory', async () => {
+    const { runCommand } = await import('../../../src/run')
+
+    await runCommand('_dev', ['fixtures/app'])
+
+    expect(initialize).toHaveBeenCalledWith(
+      expect.objectContaining({ cwd: expect.stringMatching(/fixtures[/\\]app$/) }),
+      expect.any(Object),
+    )
+  })
+
+  it('should use the test port as a loopback-only listen override', async () => {
+    vi.stubEnv('_PORT', '4321')
+    const { runCommand } = await import('../../../src/run')
+
+    await runCommand('_dev', [])
+
+    expect(initialize).toHaveBeenCalledWith(
+      expect.any(Object),
+      expect.objectContaining({
+        listenOverrides: {
+          port: '4321',
+          hostname: '127.0.0.1',
+          showURL: false,
+        },
+      }),
+    )
+  })
+})