Oleg Isonen
d5b3f3ab80
## Summary This consolidates the reported MCP reliability fixes into one delivery. - validate all inserted fragment expressions with the shared runtime rules and reject text/expression children when component content models require elements - return an actionable error for unsupported existing-resource references in JSX - preserve siblings rendered before expression children - accept unresolved CSS-variable shorthand expansion and eliminate dynamic-alt/`htmlFor` audit false positives - resolve exposed underscore MCP names during focused discovery - omit unavailable stopped-preview fields and restart stale iterative previews for external clients - bound single and responsive screenshot capture, return `SCREENSHOT_TIMEOUT`, and discard failed reusable browser sessions - dispose previews when shared MCP runs fail or stdio clients disconnect, including complete Windows process-tree cleanup - resolve generated route templates from the CLI-managed preview workspace during responsive verification - retry a browser that exits during rendered-audit startup and report sanitized exit diagnostics with a concrete browser-path recovery action - materialize complete current session data before preview generation so route order and project styles cannot collapse from missing lazy namespaces - always include CLI and Node.js version fields in generated issue reports, with explicit legacy-client fallbacks - document the updated preview and screenshot contracts and regenerate the CLI manual The current branch also retains the protections already present on `main` for dry-run isolation, CSS rewrite truncation metadata, stderr-only progress, shortcut argument forwarding, strict MCP schemas, and refreshed conflict diagnostics. ## Technical choices - MCP command orchestration stays in `mcp.ts`; preview port/retry behavior lives with `mcp-preview`, and persisted checkpoint storage lives in `mcp-checkpoint`. Each module owns its matching tests. - Expression validation lives on the shared fragment input schema, reuses `listFragmentExpressions`, and emits the same structured validation issues as prop bindings, so JSX-derived and structured fragments follow one contract across fragment, collection, and runtime UI insertion. - Element-child requirements come from component registry content models during fragment insertion; no component names are hardcoded in the JSX parser. `CollapsibleTrigger` metadata now matches its enforced `asChild` implementation. - Stopped preview status returns only `running: false`; unavailable `url`, `pid`, and `mode` fields are optional and omitted from JSON. - Explicit `preview.start` restarts a stale compatible iterative preview; managed screenshots keep their optimized refresh path. - Screenshot operations share one timeout utility. A single capture or complete responsive batch is bounded after preview readiness; lower-level CDP deadlines use the same stable error code. - Failed managed captures close and forget their browser session. A closed browser session cannot restart itself while cancellation is in progress, which prevents orphaned Chromium processes. - One ownership helper disposes one-shot and multi-project MCP hosts on success or failure. Shared `mcp run` hosts dispose in one `finally` boundary, long-running MCP hosts dispose on connection close, and Windows uses `taskkill /T /F` instead of killing only the npm wrapper. - Framework template readers receive the absolute template directory captured from the build root, so later async work cannot redirect them to the linked project's cwd. The same option drives cleanup for React Router, Remix, and Vike. - Browser startup gets one bounded retry before a rendered capture batch fails. Persistent failures report only the exit code, signal, or spawn error code plus the supported `WEBSTUDIO_BROWSER_PATH` recovery action; local paths and raw browser output are not exposed. - CLI and MCP preview share one session materializer that ensures the canonical Builder namespace set before writing `.webstudio/data.json`. Serialization rejects incomplete snapshots instead of converting missing style/instance namespaces into valid-looking empty arrays, and preview freshness records the post-materialization project version. - The CLI injects its package version and `process.versions.node`; issue formatting now keeps both fields visible even for legacy reports that omit runtime metadata. ## Checklist - [x] Add regression coverage for every changed behavior - [x] Demonstrate new regression tests fail without the corresponding fixes and pass with them - [x] Run affected package test suites and typechecks - [x] Run lint, package-boundary, and generated API checks - [x] Review fixture impact — no fixture inputs or outputs are affected - [x] Review documentation impact and update the authoritative MCP CLI manual source/generated output - [x] Run the complete local agent evaluation suite ## Verification - `@webstudio-is/project-build`: 2,090 tests passed - MCP asset query result modes are preserved across create, read, and update serialization - complete local agent evaluation suite: all 5 fixtures passed, 1,308,276 aggregate tokens - `@webstudio-is/react-sdk`: 140 tests passed - `@webstudio-is/template`: 43 tests passed - `webstudio` CLI: 956 tests passed - issue reporter: 5 targeted tests passed - MCP host disposal regression was demonstrated failing without the shared ownership boundary and passing with it - relevant package typechecks passed - `pnpm lint` passed - `pnpm check:package-boundaries` passed - `pnpm check:generated-api` passed - generated-doc tests, typecheck, sync, and regeneration passed; the aggregate clean-tree command reports the intentionally changed generated CLI manual - stalled single capture, stalled four-viewport capture, startup retry across a four-viewport batch, sanitized browser-exit diagnostics, complete preview materialization, post-refresh version tracking, closed-session restart, Windows process-tree cleanup, and preview-workspace regressions were demonstrated failing without their fixes and passing with them ## Known limitations - External `baseUrl` screenshots remain caller-owned and intentionally do not regenerate, restart, or stop that external server. Closes #6034 Closes #6035 Closes #6038 Closes #6042 Closes #6043 Closes #6044 Closes #6045 Closes #6046 Closes #6047 Closes #6048 Closes #6049 Closes #6050 Closes #6051 Closes #6052 Closes #6059 Closes #6060
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.