Running `npm run wp-dev` fails with "Invalid Argument" error

Question

I'm working through the faust.js documentation to create a headless WordPress site with Next.js. I can't get past step two: https://faustjs.org/docs/tutorial/learn-faust/#2-set-up-headless-wordpress-backend

When I run npm run wp-dev in the fresh install, I get the following error (full error below):

Error: Could not create directory "/var/www/html/wp-content/B&ce<%#Yl&k0-&2&=BKkTuOo,U%me@Uj$0U&": Invalid argument.

I've tried using npm versions 22, 21, 18, and 16. How can I troubleshoot this error?

NPM 21.4.0
Windows 11

Full error:

$ npm run wp-dev

> [email protected] wp-dev
> npx @wp-now/wp-now start --blueprint faust-tutorial-blueprint.json

Starting the server......
directory: C:\Users\jill\projects\faust-tutorial
mode: playground
php: 8.0
wp: 6.8.3 (resolved from alias: latest)
WordPress 6.8.3 folder already exists. Skipping download.
SQLite folder already exists. Skipping download.
blueprint steps: 1
Error: Could not create directory "/var/www/html/wp-content/B&ce<%#Yl&k0-&2&=BKkTuOo,U%me@Uj$0U&": Invalid argument.
    at descriptor.value (C:\Users\jill\AppData\Local\npm-cache\_npx\7c65af5c66ec2a7e\node_modules\@php-wasm\node\index.cjs:72685:17)
    at installAsset (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:1106:15)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async Object.installPlugin (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:1157:34)
    at async o (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:9440:30)
    at async Object.run (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:9367:23)
    at async runBlueprintSteps (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:9475:3)
    at async startWPNow (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-now/wp-now/main.js:739:5)
    at async startServer (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-now/wp-now/main.js:1003:42)
    at async Object.handler (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-now/wp-now/main.js:1184:25) {
  [cause]: [<generic error, no stack>] {
    name: 'ErrnoError',
    node: undefined,
    setErrno: [Function (anonymous)],
    errno: 28,
    message: 'FS error'
  }
}
Error: Error when executing the blueprint step #0 ({"step":"installPlugin","pluginZipFile":{"resource":"wordpress.org/plugins","slug":"wp-graphql"}}) : Could not create directory "/var/www/html/wp-content/B&ce<%#Yl&k0-&2&=BKkTuOo,U%me@Uj$0U&": Invalid argument.
    at Object.run (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:9370:37)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async runBlueprintSteps (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:9475:3)
    ... 2 lines matching cause stack trace ...
    at async Object.handler (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-now/wp-now/main.js:1184:25) {
  [cause]: Error: Could not create directory "/var/www/html/wp-content/B&ce<%#Yl&k0-&2&=BKkTuOo,U%me@Uj$0U&": Invalid argument.
      at descriptor.value (C:\Users\jill\AppData\Local\npm-cache\_npx\7c65af5c66ec2a7e\node_modules\@php-wasm\node\index.cjs:72685:17)
      at installAsset (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:1106:15)
      at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
      at async Object.installPlugin (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:1157:34)
      at async o (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:9440:30)
      at async Object.run (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:9367:23)
      at async runBlueprintSteps (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:9475:3)
      at async startWPNow (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-now/wp-now/main.js:739:5)
      at async startServer (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-now/wp-now/main.js:1003:42)
      at async Object.handler (file:///C:/Users/jill/AppData/Local/npm-cache/_npx/7c65af5c66ec2a7e/node_modules/@wp-now/wp-now/main.js:1184:25) {
    [cause]: [<generic error, no stack>] {
      name: 'ErrnoError',
      node: undefined,
      setErrno: [Function (anonymous)],
      errno: 28,
      message: 'FS error'
    }
  }
}
Failed to start the server: Error when executing the blueprint step #0 ({"step":"installPlugin","pluginZipFile":{"resource":"wordpress.org/plugins","slug":"wp-graphql"}}) : Could not create directory "/var/www/html/wp-content/B&ce<%#Yl&k0-&2&=BKkTuOo,U%me@Uj$0U&": Invalid argument.

I'm one of the maintainers of Faust.js. I couldn't replicate this on Mac, but based on the Windows context, the use of npm degit might be running into permission issues. As a first step to try and get the Faust tutorial to work could you try: sh git clone [email protected]:wpengine/faustjs.git && cd faustjs/examples/next/tutorial && nvm use && npm install && npm run wp-dev Please let us know if this resolves the issue for you. — Colin Murphy
– Colin Murphy, Commented Nov 6 at 18:18
@ColinMurphy thanks for maintaining Faust! Our team is excited to use it (just testing it out first). I'm almost positive it's a Windows issues. I tried the command you provided above (although removed sh from the beginning, and added a version number after nvm use because my system requires it. Seeing the same error unfortunately. — Jillian Hoenig
– Jillian Hoenig, Commented Nov 6 at 22:37
Great to hear that you are testing out Faust and sorry that didn't work for you. Looking at the error again, it looks like the error is due to wp-now and wpgraphql and downloading the plugin. executing...` If you comment out the plugins and install them manually install them through the WordPress plugin manager would that work? If you can comment the following lines in the faust-tutorial-blueprint.json file: ``` "plugins": ["wp-graphql", "faustwp"], ``` And then run npm wp-now to see if that works. If none of this works, let us know and we see what the next steps are. — Colin Murphy
– Colin Murphy, Commented Nov 7 at 16:09
Another idea would be to try and install the latest wp-now e.g. npm install @wp-now/wp-now@latest and then run npm run wp-dev to see if that works. — Colin Murphy
– Colin Murphy, Commented Nov 7 at 16:10

Jillian Hoenig · Accepted Answer · 2025-11-10 17:01:43Z

1

Thank you @ColinMurphy for commenting the answer above. Removing line 13 from faust-tutorial-blueprint.json fixed the issue. Once that line was removed, I was able to npm run wp-dev and install those plugins through the wordpress UI.

I believe this was a Windows 11 problem, but have not confirmed one way or the other.

answered Nov 10 at 17:01

Jillian Hoenig

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Colin Murphy · Accepted Answer · 2025-11-11 10:10:27Z

1

Thanks @Jillian Hoenig for confirming this was resolved.

We have added an issue to our sprint to rewrite the Faust tutorial to use wp-env instead of wp-now - https://github.com/wpengine/faustjs/issues/2211

We feel this might be more reliable going forward for all systems. Additionally this is something we have used recently in our hwptoolkit examples.

I can let you know once this is implemented.

answered Nov 11 at 10:10

Colin Murphy

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Jillian Hoenig Nov 17 at 17:54

Awesome! Thanks for all your help!

Colin Murphy · Accepted Answer · 2025-11-27 09:27:39Z

0

@Jillian Hoenig

We have now fixed the tutorial to use wp-env instead of wp-now - https://faustjs.org/docs/tutorial/learn-faust/

Thank you so much for letting us know about the issues you were having and hopefully this will fix any issues.

answered Nov 27 at 9:27

Colin Murphy

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