Oleg Isonen
6d2389ee54
## Summary - start managed POSIX preview servers in their own process group - terminate the complete preview process group from `preview.stop` - clean up the owned preview group before propagating `SIGHUP`, `SIGINT`, or `SIGTERM` - preserve the existing child-process fallback on Windows - keep standalone `webstudio preview` signal behavior unchanged ## Root cause The managed preview controller spawned an npm wrapper and stopped only that direct child with `ChildProcess.kill()`. React Router runs below that wrapper, so the dev server could survive as an orphan. Its inherited stdout/stderr pipes could also keep `webstudio mcp run` alive after the manifest had completed. ## Impact `preview.stop` now terminates the npm wrapper and all descendants. If the CLI is terminated while it owns a managed preview, it kills that process group before re-propagating the original signal to itself. ## Todo - [x] Reproduce the missing process-group cleanup in regression tests - [x] Isolate managed POSIX previews in their own process group - [x] Stop the full group on `preview.stop` - [x] Stop the full group on CLI termination signals - [x] Preserve standalone preview behavior - [x] Run an independent real subprocess test with an npm wrapper and long-lived grandchild - [x] Review documentation impact — existing MCP documentation already describes `preview.stop` as ending the owned preview, so no docs change is required - [x] Verify fixture impact — no fixture inputs or generated outputs are affected ## Verification - `pnpm --filter webstudio test` — 58 files, 945 tests passed - `pnpm --filter webstudio typecheck` — passed - targeted `oxlint`, `oxfmt`, and `git diff --check` — passed - regression tests were demonstrated failing without the process-group and signal cleanup, then passing with it - independent real-process test on macOS / Node 22.22.1: - `preview.stop` removed the npm wrapper, server, and long-lived grandchild in 458 ms; harness exited in 0.93 s - parent `SIGTERM` removed the complete process group in 0.01 s; harness exited with expected status 143 - all observed PIDs were absent afterward - agent evaluations were not run because they require separate explicit approval Closes #5958
Webstudio CLI
The Webstudio CLI helps you to link, sync and build projects from Webstudio Cloud. This README will guide you through the process of setting up a Webstudio project on your local machine and continually sync it with the cloud.
Prerequisites: Installing Node.js
You need Node.js to use the Webstudio CLI. If Node.js is already installed in your system, you can skip ahead to the section on installing the Webstudio CLI.
To install Node.js using NVM, first install NVM by running:
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.5/install.sh | bash
Once NVM is installed, you can install Node.js version 22 by running:
nvm install 22
Verify your Node.js installation by checking its version:
node --version
Installing the Webstudio CLI
To get started with the Webstudio CLI:
-
Download and install the CLI using the following command:
npm install -g webstudio@latest -
Confirm the installation by checking the CLI version:
webstudio --version -
To keep your CLI updated, use the same command used for installation whenever a new release is available.
Initiating a Webstudio Project
Now, you can run a Webstudio project on your local machine using this command:
webstudio
This will initiate the flow to connect your Webstudio Cloud project and build it in your local computer. The default flow will guide you through the steps. You can also perform all the operations individually using independent commands.
Commands
Here is the list of independent commands:
- version
- help
- link
- sync
- build
link
The link command stores access to a Webstudio Cloud project. MCP clients use that connection to read and edit the latest Builder build directly; the project does not need to be published or synchronized first.
Shell-capable agents can call MCP tools directly as CLI subcommands immediately after linking. This does not require MCP client configuration or a client restart:
webstudio meta.index
webstudio components.search '{"brief":"button"}'
webstudio insert-fragment --input-file .temp/insert-fragment.json --dry-run
.temp/insert-fragment.json:
{
"parentInstanceId": "<parent-id>",
"fragment": "<ws.element ws:tag='section' />"
}
The explicit equivalent is webstudio mcp single-op-call <tool> '<json>'.
Use webstudio connect <client> only when you want persistent native MCP tools
inside Claude Code, Codex, Cursor, or VS Code. A persistent client may need to
reconnect after its configuration or cached tool catalog changes.
See the Webstudio MCP documentation for setup, discovery, editing, verification, and safety guidance.
You can link a project from Webstudio Cloud with the following command:
webstudio link
This command will prompt you to paste a link which you can create using the Share option in your project.
Make sure to provide Build access when generating the link in Webstudio Cloud.
sync
Once the project is linked, use the sync command to sync it with the cloud:
webstudio sync
Make sure to publish the project in Webstudio Cloud before running the sync command in your local Webstudio project.
sync is only for downloading a published project export. It is not part of the MCP editing workflow.
build
Now, you can build your project with the build command:
webstudio build
During this phase, the CLI establishes the necessary routes and pages, scaffolding the entire application using the default Remix template. Additionally, all assets, such as images and fonts are downloaded to the assets folder inside the public directory.
Once the project is scaffolded, you can run npm install and then npm run dev to run your app in development mode.
If you want to build a production version of the app, you can run npm run build.
Deployment
Vercel
Once you've built the project locally, you can use the Vercel CLI to deploy your project directly to Vercel:
vercel deploy
Follow the instructions here to install the vercel CLI. We plan to add more deployment targets in future.
Netlify
If you want to deploy to netlify, you can use Netlify CLI to deploy your project directly to Netlify:
netlify deploy
You can configure the project to support netlify serverless/edge-functions respectively, as deployment target at the time of initially setting up your project. Please check the initiating-a-webstudio-project section.
You can manually change it using the build command. For serverless functions:
webstudio build --template netlify
Important Notes
If you use vercel build before vercel deploy, make sure to clean your app folder in the project afterward.
Vercel injects a few files to support and deploy Remix using their CLI, but these files are not necessary for your project when you use it locally.