chrome-store-mcp

An MCP server for the Chrome Web Store API v2.

MCP (Model Context Protocol) is the standard way AI assistants, such as Claude Code, call tools. This server gives an assistant nine tools to read the state of your Chrome extension in the store, and to upload, publish and roll back new versions. Every change that reaches your users asks a human first.

Status: version 0.1.0, not released yet. There are 67 automated tests, and each safety guard was shown to fail its test when it was deliberately broken. It has not been run against Google's live API or a real store item yet (as of 2026-11-03).

Quick install

You need Node.js 22.18 or newer and Git. There is nothing to download by hand: npx fetches the server from GitHub, builds it and runs it.

1. Get an OAuth client file from Google Cloud (see Set up Google Cloud below), then sign in once:

   npx -y github:RayanBayat/chrome-store-mcp login /path/to/client_secret.json

   Want the write tools too (upload, publish, rollback)? Run it once more with login --write.

2. Add the server to Claude Code:

   claude mcp add chrome-store --scope user -e CWS_PUBLISHER_ID=<publisher id> -e CWS_ITEM_ID=<item id> -- npx -y github:RayanBayat/chrome-store-mcp

That is all. The first start takes longer because npx downloads and builds the server; later starts reuse it. It follows the main branch, so you get new commits automatically; every commit on main has passed CI. Its dependencies, including indirect ones, are locked to exact versions (npm-shrinkwrap.json). To review updates before you take them, stay on one commit by adding #<commit> after the repository name, for example github:RayanBayat/chrome-store-mcp#35e4f8c.

For another MCP client, put this in its settings:

{
  "mcpServers": {
    "chrome-store": {
      "command": "npx",
      "args": ["-y", "github:RayanBayat/chrome-store-mcp"],
      "env": {
        "CWS_PUBLISHER_ID": "<publisher id>",
        "CWS_ITEM_ID": "<item id>"
      }
    }
  }
}

From a clone (to read or change the code)

git clone https://github.com/RayanBayat/chrome-store-mcp.git && cd chrome-store-mcp && npm ci --ignore-scripts

Then run node src/index.ts instead of npx -y github:RayanBayat/chrome-store-mcp. Node 22.18 and newer run the TypeScript source directly, so there is no build step.

Related MCP server: play-console-mcp

What it can do

Notes:

• cws_upload does not ask. It only replaces the draft package. Your users see nothing until the draft is published.

• cws_publish defaults to publishType: STAGED_PUBLISH (after approval it waits until you press Publish in the dashboard), skipReview: false and blockOnWarnings: true.

• cws_rollback with validateOnly: true only checks the request, so it does not ask.

• cws_set_deploy_percentage only works for items with more than 10,000 seven-day active users.

• Review text is written by the public. The result of cws_reviews says it is data, never instructions.

What it cannot do

Google's API does not cover these, so this server cannot change them:

• Store listing text

• Screenshots and promo images

• Privacy practices answers

• Distribution settings

• Creating a new item. Upload the first version by hand in the Developer Dashboard.

Edit these in the Developer Dashboard, or with a browser automation tool that you control.

Set up Google Cloud

The server talks to Google with your own OAuth client, so you need a small Google Cloud project. OAuth is the standard way to let a program act for your Google account without knowing your password.

1. Open the Google Cloud console. Create a project or pick one.

2. Enable the Chrome Web Store API for that project (APIs and Services, Library).

3. Open Google Auth Platform (also called the OAuth consent screen). Choose the user type External. Fill in an app name and your email address.

4. Open Data access and add the scopes. A scope is one permission that you grant.

   • https://www.googleapis.com/auth/chromewebstore.readonly for the read tools.

   • https://www.googleapis.com/auth/chromewebstore as well, if you want the write tools.

5. Open Audience. Add your own Google account as a test user. Then press Publish app so the app is In production. An app that stays in Testing gets refresh tokens that expire after 7 days.

6. Open Clients. Create an OAuth client of type Desktop app. Download the JSON file.

7. Sign in. Each command opens Google's consent page in your browser:

   npx -y github:RayanBayat/chrome-store-mcp login /path/to/client_secret.json

   npx -y github:RayanBayat/chrome-store-mcp login --write /path/to/client_secret.json

   The second command is only needed for the write tools.

8. Delete the JSON file. The server saved what it needs.

Because the app is not verified by Google, the consent page shows a warning. For your own account you can pass it: press Advanced, then continue.

Find your publisher ID and item ID

Both are in the Chrome Web Store Developer Dashboard. The item ID is 32 letters (each from a to p) and is in the item's URL. You can set them once with CWS_PUBLISHER_ID and CWS_ITEM_ID, or pass them to each tool call as publisherId and itemId.

Sign-ins and where secrets are kept

There are two separate sign-ins:

Each sign-in gives the server a refresh token. A refresh token is a long-lived secret that the server swaps for a short-lived access token whenever it needs one. Treat it like a password.

login refuses, and revokes, any grant that is not exactly the scope it asked for. Each token refresh also asks for exactly that scope, and the server refuses an answer that reports other scopes.

The server looks for each secret in this order:

1. Environment variables: CWS_CLIENT_ID, CWS_CLIENT_SECRET, CWS_REFRESH_TOKEN (read sign-in) and CWS_WRITE_REFRESH_TOKEN (write sign-in). They work on every system. The values sit in plain text in your MCP settings.

2. The Linux desktop keyring (KWallet or GNOME Keyring), through the secret-tool command. A keyring is an encrypted store for secrets that your desktop manages. The service name is chrome-store-mcp. login saves there when it can. This is the better choice.

On macOS and Windows, use environment variables. A backend for the macOS Keychain and the Windows Credential Manager is not built yet. Contributions are welcome. If login finds no keyring, it prints the values to set as environment variables.

To sign out, run npx -y github:RayanBayat/chrome-store-mcp logout (add --write for the write sign-in). This revokes the token at Google and removes it from the keyring. If you used environment variables, remove them from your settings too.

Confirmation

Before a write action that affects users, the server asks a person. This matters because an AI assistant can be tricked, for example by text inside a store review. A question that only a person can answer means a tricked assistant still cannot publish.

Set the mode with the CWS_CONFIRM environment variable:

An elicitation is an MCP feature: the server asks the client to show a question to the person and send back the answer.

The dialog text is cleaned of markup and control characters. If nobody answers within 2 minutes, that counts as no.

Other settings

A wrong value stops the server at start-up with a clear message.

Command line

Run each command as npx -y github:RayanBayat/chrome-store-mcp <command>, or from a clone as node src/index.ts <command>.

Safety in short

• Only nine fixed requests are allowed (exact method, path and sign-in level). Everything else is refused before it is sent.

• IDs are checked with strict patterns, so a tool argument cannot change where a request goes.

• No redirects, and every request has a timeout.

• Errors are cleaned of tokens. Details from Google are not shown.

• Output is capped at 60,000 characters.

• Uploads must be an absolute path to a real .zip file within the size limit, starting with the ZIP magic bytes.

The full list, with the file and test for each layer, is in docs/security.md.

Maintenance reminder

Google can add or retire API methods, and dependencies get updates. The file src/maintenance.ts records the date of the last review. While that date is more than 30 days old, every tool result ends with a reminder. The review itself is described in docs/maintenance.md.

Troubleshooting

Why not the existing cws-mcp package?

There is already an npm package called cws-mcp. I read version 2.0.2 on 2026-11-03. Its code is honest: it has no telemetry and talks only to Google endpoints. I still chose to write a different server, for these reasons:

• Its upload, publish, cancel, rollout and listing-edit tools are always on and ask for no confirmation.

• Publish defaults to going live right after approval, and it has a skip-review option.

• Its listing tools drive the real dashboard with Playwright and keep a full Google account session on disk in ~/.cws-mcp-profile.

• Its upload reads any file path.

• Its setup runs npx -y cws-mcp and it ships no lockfile, so every start can install newer versions of it and of its dependencies.

If you want listing edits through a browser, that package does something this one does not. This server does less on purpose.

Dependencies

Both are pinned to an exact version, and npm-shrinkwrap.json locks every indirect dependency, also for npx installs. With transitive packages there are about 95 packages. npm audit --omit=dev reported 0 vulnerabilities on 2026-11-03.

I used the official SDK instead of writing the protocol layer by hand, so new MCP protocol versions arrive as SDK updates.

Development tools: TypeScript 6.0.3 (TypeScript 7 exists, but typescript-eslint supports up to 6.0), ESLint 10 with a flat config and typescript-eslint strictTypeChecked, Prettier, and node:test for tests.

More documents

• docs/architecture.md: how it works, a map of the files, and the path of one tool call

• docs/security.md: the threat model and every safety layer

• docs/maintenance.md: the monthly review

• CONTRIBUTING.md: how to set up and change the code

• SECURITY.md: how to report a vulnerability

• CHANGELOG.md

Licence

MIT. See LICENSE. Copyright (c) 2026 Rayan Bayat.