diff --git a/acceptance/cmd/workspace/apps/run-local-node/app/.npmrc b/acceptance/cmd/workspace/apps/run-local-node/app/.npmrc
new file mode 100644
index 00000000000..c43162960a8
--- /dev/null
+++ b/acceptance/cmd/workspace/apps/run-local-node/app/.npmrc
@@ -0,0 +1,3 @@
+; With nothing to install, the one thing npm still reaches the registry for is its check for
+; a newer npm, and the acceptance proxy rejects that. The install and the audit stay local.
+update-notifier=false
diff --git a/acceptance/cmd/workspace/apps/run-local-node/app/app.js b/acceptance/cmd/workspace/apps/run-local-node/app/app.js
index 74686d09a82..4e47e5c9cda 100644
--- a/acceptance/cmd/workspace/apps/run-local-node/app/app.js
+++ b/acceptance/cmd/workspace/apps/run-local-node/app/app.js
@@ -1,27 +1,26 @@
-const express = require('express');
-const app = express();
-const port = process.env.PORT || 8000;
+const http = require('node:http');
 
-// Root route
-app.get('/', (req, res) => {
-  res.json({
-    message: 'Hello From App',
-    timestamp: new Date().toISOString(),
-    status: 'running'
-  });
-});
+// Standard library only: acceptance tests run with the network disabled, so the
+// app cannot install anything from the NPM registry.
+
+// The CLI sets PORT alongside DATABRICKS_APP_PORT. Unset, listen() would pick a random port
+// and the run would fail as a proxy timeout instead.
+const port = process.env.PORT;
+if (!port) throw new Error('PORT is not set');
 
-app.get('/shutdown', (req, res) => {
-  console.log('Server closed')
-  // Add a small delay to ensure response is sent before exit
-  setTimeout(() => {
-    process.exit(0);
-  }, 1000);
+const server = http.createServer((req, res) => {
+  if (req.url === '/shutdown') {
+    // close() waits for open connections, so the response must end this one or the proxy holds it.
+    res.setHeader('Connection', 'close');
+    res.end();
+    server.close();
+    return;
+  }
+
+  res.writeHead(200, { 'Content-Type': 'application/json' });
+  res.end(JSON.stringify({ message: 'Hello From App' }) + '\n');
 });
 
-// Start the server
-app.listen(port, () => {
+server.listen(port, '127.0.0.1', () => {
   console.log(`Server is running on port ${port}`);
 });
-
-module.exports = app;
diff --git a/acceptance/cmd/workspace/apps/run-local-node/app/app.yml b/acceptance/cmd/workspace/apps/run-local-node/app/app.yml
index bc02e198203..8acf26d0927 100644
--- a/acceptance/cmd/workspace/apps/run-local-node/app/app.yml
+++ b/acceptance/cmd/workspace/apps/run-local-node/app/app.yml
@@ -1,4 +1,3 @@
 command:
-  - npm
-  - run
-  - run-app
+  - node
+  - app.js
diff --git a/acceptance/cmd/workspace/apps/run-local-node/app/build.js b/acceptance/cmd/workspace/apps/run-local-node/app/build.js
new file mode 100644
index 00000000000..58421926421
--- /dev/null
+++ b/acceptance/cmd/workspace/apps/run-local-node/app/build.js
@@ -0,0 +1,3 @@
+// A file rather than an inline command in package.json, so the asserted output does
+// not depend on how npm's shell quotes it, which differs on Windows.
+console.log('Build script ran');
diff --git a/acceptance/cmd/workspace/apps/run-local-node/app/package.json b/acceptance/cmd/workspace/apps/run-local-node/app/package.json
index 15e06e17ffb..e3b250f18dc 100644
--- a/acceptance/cmd/workspace/apps/run-local-node/app/package.json
+++ b/acceptance/cmd/workspace/apps/run-local-node/app/package.json
@@ -2,12 +2,7 @@
     "name": "app",
     "version": "1.0.0",
     "description": "A simple Node.js app",
-    "main": "app.js",
     "scripts": {
-        "run-app": "node app.js",
-        "build": "echo 'Building app...'"
-    },
-    "dependencies": {
-        "express": "^5.1.0"
+        "build": "node build.js"
     }
 }
diff --git a/acceptance/cmd/workspace/apps/run-local-node/out.test.toml b/acceptance/cmd/workspace/apps/run-local-node/out.test.toml
index 3ef9121aba6..e90b6d5d1ba 100644
--- a/acceptance/cmd/workspace/apps/run-local-node/out.test.toml
+++ b/acceptance/cmd/workspace/apps/run-local-node/out.test.toml
@@ -1,3 +1,3 @@
-Local = false
+Local = true
 Cloud = false
 EnvMatrix.DATABRICKS_BUNDLE_ENGINE = ["direct"]
diff --git a/acceptance/cmd/workspace/apps/run-local-node/output.txt b/acceptance/cmd/workspace/apps/run-local-node/output.txt
index 0185dbe5234..e6b0bd0a642 100644
--- a/acceptance/cmd/workspace/apps/run-local-node/output.txt
+++ b/acceptance/cmd/workspace/apps/run-local-node/output.txt
@@ -1,12 +1,28 @@
+
+=== Prepare environment runs the build script, and the entry point overrides app.yml
+
+>>> grep -x Build script ran ../LOG.prepare
+Build script ran
+
+>>> grep -x Running command: node -e console.log('Hello, world') ../LOG.prepare
 Running command: node -e console.log('Hello, world')
+
+>>> grep -x Hello, world ../LOG.prepare
 Hello, world
 
-=== Starting the app in background...
-=== Waiting
-=== Checking app is running...
->>> curl -s -o - http://127.0.0.1:$(port)
-{"message":"Hello From App","timestamp":"[TIMESTAMP]","status":"running"}
+=== Proxy forwards to the app
+
+>>> retry --until Hello From App curl -sS http://127.0.0.1:[PROXY_PORT]
+{"message":"Hello From App"}
+
+=== Debug mode reports the debugger port, and node listens on it
+
+>>> retry grep -x To debug your app, attach a debugger to port [DEBUG_PORT] LOG.run
+To debug your app, attach a debugger to port [DEBUG_PORT]
+
+>>> grep Debugger listening on ws://127.0.0.1:[DEBUG_PORT]/ LOG.run
+Debugger listening on ws://127.0.0.1:[DEBUG_PORT]/[UUID]
+
+=== Shutting the app down
 
-=== Sending shutdown request...
->>> curl -s -o /dev/null http://127.0.0.1:$(port)/shutdown
-Process terminated
+>>> curl -sS -o /dev/null http://127.0.0.1:[PROXY_PORT]/shutdown
diff --git a/acceptance/cmd/workspace/apps/run-local-node/script b/acceptance/cmd/workspace/apps/run-local-node/script
index 3701e6fd697..58a139975b5 100755
--- a/acceptance/cmd/workspace/apps/run-local-node/script
+++ b/acceptance/cmd/workspace/apps/run-local-node/script
@@ -1,52 +1,45 @@
 cd app
 
-# We first run the command with different entry point which starts unblocking script
-# so we don't need to start it in background. It will install the dependencies as part of the command
-trace $CLI apps run-local --prepare-environment --entry-point test.yml 2>&1 | grep -w "Hello, world"
-
-read -r PORT DEBUG_PORT PROXY_PORT <<< "$(free_port.py 3)"
+# Ports are allocated per run so that tests in parallel worktrees do not collide.
+read -r APP_PORT PROXY_PORT DEBUG_PORT PREPARE_PORT <<< "$(free_port.py 4)"
+add_repl.py "$PROXY_PORT" PROXY_PORT
+add_repl.py "$DEBUG_PORT" DEBUG_PORT
+
+# The app and the proxy start asynchronously; allow up to 15s for them to come up.
+export RETRY_MAX_ATTEMPTS=30
+
+title "Prepare environment runs the build script, and the entry point overrides app.yml\n"
+# npm reaches no registry here: nothing to install, and app/.npmrc turns off its update check.
+# The build script runs only if the install succeeded, so the first grep covers both halves.
+trace $CLI apps run-local --prepare-environment --entry-point test.yml --port "$PREPARE_PORT" &> ../LOG.prepare
+trace grep -x "Build script ran" ../LOG.prepare
+trace grep -x "Running command: node -e console.log('Hello, world')" ../LOG.prepare
+trace grep -x "Hello, world" ../LOG.prepare
 
 cleanup() {
-    # Kill any still running processes on these ports when the script exits
-    kill_port.py $PORT $DEBUG_PORT $PROXY_PORT
+    local status=$?
+    # Reap by port rather than by $PID, and only on failure, for the reasons in
+    # ../run-local/script. The debug port is here too because node binds the inspector before
+    # it runs app.js, so it is the only handle on an app that died before it listened.
+    [ "$status" -eq 0 ] || kill_port.py "$APP_PORT" "$PROXY_PORT" "$DEBUG_PORT"
 }
 
-trap cleanup EXIT
-
-title "Starting the app in background..."
-trace $CLI apps run-local --prepare-environment --debug --port "$PROXY_PORT" --debug-port "$DEBUG_PORT" --app-port "$PORT" > ../out.run.txt 2>&1 &
+# app/package.json selects the CLI's Node code path (runlocal.NewApp); without it the app is
+# treated as Python and --debug no longer sets NODE_OPTIONS.
+trace $CLI apps run-local --debug --port "$PROXY_PORT" --debug-port "$DEBUG_PORT" --app-port "$APP_PORT" &> ../LOG.run &
 PID=$!
-# Ensure background process is killed on script exit
-trap '(kill $PID >/dev/null 2>&1) 2>/dev/null || true' EXIT
+trap cleanup EXIT
 cd ..
 
-title Waiting for the app to start...
-# Use a loop to check for the startup message instead of tail/sed which can be unreliable on Windows
-# due to file locking, buffering issues, and different text processing behavior across Windows versions.
-# A simple grep loop is more robust across platforms.
-while [ -z "$(grep -o "Server is running on port " out.run.txt 2>/dev/null)" ]; do
-    sleep 1
-done
-
-# Make sure the proxy is ready to serve requests
-while [ -z "$(grep -o "To access your app go to " out.run.txt 2>/dev/null)" ]; do
-    sleep 1
-done
-
-title "Checking app is running..."
-trace curl -s -o - http://127.0.0.1:$PROXY_PORT | grep -w "Hello From App"
-
-title "Sending shutdown request..."
-trace curl -s -o /dev/null  http://127.0.0.1:$PROXY_PORT/shutdown || true
-
-# We need to wait for the app to shutdown before we can exit the test meaning wait until the
-# server is closed. We need to poll because the server is closed asynchronously.
-while [ -z "$(grep -o "Server closed" out.run.txt 2>/dev/null)" ]; do
-    sleep 1
-done
+title "Proxy forwards to the app\n"
+trace retry --until "Hello From App" curl -sS "http://127.0.0.1:$PROXY_PORT"
 
-# Wait for the background process to actually terminate
-wait $PID 2>/dev/null || true
-echo "Process terminated"
+title "Debug mode reports the debugger port, and node listens on it\n"
+# The CLI prints this only after the proxy accepts connections, so the curl above can beat it.
+# node's line below needs no retry: it is written before the app listens, so the curl proves it.
+trace retry grep -x "To debug your app, attach a debugger to port $DEBUG_PORT" LOG.run
+trace grep "Debugger listening on ws://127.0.0.1:$DEBUG_PORT/" LOG.run
 
-rm out.run.txt
+title "Shutting the app down\n"
+trace curl -sS -o /dev/null "http://127.0.0.1:$PROXY_PORT/shutdown"
+wait $PID
diff --git a/acceptance/cmd/workspace/apps/run-local-node/test.toml b/acceptance/cmd/workspace/apps/run-local-node/test.toml
index 2b6bb4bdda4..023a62e4f8c 100644
--- a/acceptance/cmd/workspace/apps/run-local-node/test.toml
+++ b/acceptance/cmd/workspace/apps/run-local-node/test.toml
@@ -1,26 +1,13 @@
-Badness = "need to enable NPM registry access"
 Cloud = false
-Local = false
+Local = true
 RecordRequests = false
-Timeout = '2m'
-TimeoutWindows = '10m'
 
+# npm install writes package-lock.json even with nothing to install, and older npm versions
+# also create node_modules for their own copy of the lockfile.
 Ignore = [
     'node_modules',
     'package-lock.json'
 ]
 
-[[Repls]]
-Old='curl/[0-9]+\.[0-9]+\.[0-9]+'
-New='curl/(version)'
-
-[[Repls]]
-Old='127.0.0.1:[0-9]+'
-New='127.0.0.1:$(port)'
-
-[[Repls]]
-Old='To debug your app, attach a debugger to port [0-9]+'
-New='To debug your app, attach a debugger to port $(debug_port)'
-
-[EnvMatrix]
-  DATABRICKS_BUNDLE_ENGINE = ["direct"]
+# The command is unrelated to bundle deployment, so run it once rather than per engine.
+EnvMatrix.DATABRICKS_BUNDLE_ENGINE = ["direct"]