diff --git a/config/scripts/build-workspace-packages.mjs b/config/scripts/build-workspace-packages.mjs
index d4984a459c0..ba32e2e4c1a 100644
--- a/config/scripts/build-workspace-packages.mjs
+++ b/config/scripts/build-workspace-packages.mjs
@@ -11,6 +11,7 @@ import {
 } from 'node:fs'
 import { createRequire } from 'node:module'
 import { dirname, join, relative, resolve } from 'node:path'
+import { resolvePnpmCliInvocation } from './pnpm-cli-invocation.mjs'
 
 const root = resolve(import.meta.dirname, '../..')
 const PACKAGES = [{ name: '@orca/process-host', dir: 'src/packages/process-host' }]
@@ -90,14 +91,11 @@ function writeStamp(packageDir, inputs) {
 
 function runPackageBuild(name) {
   // Why not @orca/process-host: this builds it, so its dist may not exist yet.
-  const pnpmEntry = process.env.npm_execpath
-  const [program, args] = /\.[cm]?js$/.test(pnpmEntry ?? '')
-    ? [process.execPath, [pnpmEntry, '--filter', name, 'build']]
-    : ['pnpm', ['--filter', name, 'build']]
-  const result = spawnSync(program, args, {
+  const { command, prefixArgs, shell } = resolvePnpmCliInvocation()
+  const result = spawnSync(command, [...prefixArgs, '--filter', name, 'build'], {
     cwd: root,
     stdio: 'inherit',
-    shell: program === 'pnpm' && process.platform === 'win32'
+    shell
   })
   if (result.error) {
     throw result.error
diff --git a/config/scripts/pnpm-cli-invocation.mjs b/config/scripts/pnpm-cli-invocation.mjs
index bac0becb6a0..856d5eb07b6 100644
--- a/config/scripts/pnpm-cli-invocation.mjs
+++ b/config/scripts/pnpm-cli-invocation.mjs
@@ -4,6 +4,8 @@ import { statSync } from 'node:fs'
 import { win32 } from 'node:path'
 
 const JS_CLI_EXTENSION = /\.[cm]?js$/i
+// Why: `npx` and `npm run` export npm's own CLI as npm_execpath, which would run npm, not pnpm.
+const NPM_OWN_CLI_PATH = /(?:^|[/\\])np[mx]-cli\.js$/i
 
 function isFile(path) {
   try {
@@ -20,7 +22,11 @@ export function resolvePnpmCliInvocation({
   pnpmHome = process.env.PNPM_HOME,
   fileExists = isFile
 } = {}) {
-  if (typeof npmExecPath === 'string' && npmExecPath.length > 0) {
+  if (
+    typeof npmExecPath === 'string' &&
+    npmExecPath.length > 0 &&
+    !NPM_OWN_CLI_PATH.test(npmExecPath)
+  ) {
     if (JS_CLI_EXTENSION.test(npmExecPath)) {
       return { command: nodeExecPath, prefixArgs: [npmExecPath], shell: false }
     }
diff --git a/config/scripts/pnpm-cli-invocation.test.mjs b/config/scripts/pnpm-cli-invocation.test.mjs
index f02a98e8c0b..333075f01e2 100644
--- a/config/scripts/pnpm-cli-invocation.test.mjs
+++ b/config/scripts/pnpm-cli-invocation.test.mjs
@@ -37,6 +37,20 @@ describe('resolvePnpmCliInvocation', () => {
     })
   })
 
+  it.each([
+    ['/usr/share/nodejs/npm/bin/npx-cli.js', 'linux', 'pnpm', false],
+    ['/usr/local/lib/node_modules/npm/bin/npm-cli.js', 'darwin', 'pnpm', false],
+    ['/Users/dev/.volta/tools/image/npm/10.8.0/bin/npm-cli.js', 'darwin', 'pnpm', false],
+    ['C:\\Program Files\\nodejs\\node_modules\\npm\\bin\\npx-cli.js', 'win32', 'pnpm.cmd', true]
+  ])(
+    'ignores the npm CLI %s that `npx` or `npm run` exports',
+    (npmExecPath, platform, command, shell) => {
+      expect(
+        resolvePnpmCliInvocation({ npmExecPath, nodeExecPath, platform, pnpmHome: '' })
+      ).toEqual({ command, prefixArgs: [], shell })
+    }
+  )
+
   it('does not wrap a Windows native pnpm.exe in node', () => {
     expect(
       resolvePnpmCliInvocation({
diff --git a/config/scripts/run-terminal-layout-parity.mjs b/config/scripts/run-terminal-layout-parity.mjs
index 7d8a48cd8f3..320e6ba66fc 100644
--- a/config/scripts/run-terminal-layout-parity.mjs
+++ b/config/scripts/run-terminal-layout-parity.mjs
@@ -13,11 +13,12 @@ import {
   writeFileSync
 } from 'node:fs'
 import { tmpdir } from 'node:os'
-import { basename, join, resolve } from 'node:path'
+import { join, resolve } from 'node:path'
 import { pathToFileURL } from 'node:url'
 import { parseArgs } from 'node:util'
 import { runProcessSync } from '@orca/process-host'
 import { describeProcessFailure } from './process-failure-message.mjs'
+import { resolvePnpmCliInvocation } from './pnpm-cli-invocation.mjs'
 const repoRoot = resolve(import.meta.dirname, '../..')
 const BUILD_STAMP = join('out', '.terminal-layout-parity-build')
 
@@ -88,16 +89,9 @@ function git(args) {
   return result.stdout.trim()
 }
 
-// npm_execpath is pnpm's JS entry (run under node), a native pnpm binary (corepack), or unset.
 function pnpm(args, cwd, env = process.env) {
-  const entry = process.env.npm_execpath
-  if (entry && /\.[cm]?js$/i.test(entry)) {
-    run(process.execPath, [entry, ...args], cwd, env)
-  } else if (entry && /pnpm/i.test(basename(entry)) && existsSync(entry)) {
-    run(entry, args, cwd, env)
-  } else {
-    run('pnpm', args, cwd, env)
-  }
+  const { command, prefixArgs } = resolvePnpmCliInvocation()
+  run(command, [...prefixArgs, ...args], cwd, env)
 }
 
 /** A detached worktree per commit, installed and built once; a failed build throws before stamping. */