LABSCO SUMMARY

Snapshots over screenshots, which is why it is quick.

Driving a browser by accessibility snapshot instead of pixels is both cheaper per step and less brittle when a layout shifts, and the vision fallback covers what the snapshot genuinely cannot see. The separate profile deserves a moment's thought before you point it at a staging login: session state persists across runs, which is convenient until it is not.

What it is

Limetest, a lightweight end-to-end testing framework with an MCP server built on Playwright. Test cases are written in natural language and executed by a model against a real browser; execution leans on Playwright's accessibility snapshot rather than pixel analysis, which is what keeps it fast and stable, and falls back to vision mode for scenarios the snapshot cannot express.

What you get

End-to-end test runs planned and executed by the model against a real Chrome instance
Snapshot-driven execution, with a vision fallback for the cases snapshot mode cannot handle
A headless mode for running the same tests inside CI
A persistent Chrome profile, so a login survives between sessions until you delete it

Requirements

An OpenAI API key — the README states it is needed to run this server in end-to-end mode, and it is passed on the launch command as --api-key. Install @limetest/mcp from npm and run npx playwright install to fetch the browser. The server launches Chrome under its own profile, stored under ms-limetest/mcp-chrome-profile in the platform cache directory; anything you log into stays there until that folder is removed. Apache 2.0, and built on Microsoft's Playwright MCP.

Setup effort

One command plus a key — npm install @limetest/mcp, then supply credentials

See installation options

USE CASES

01

Writing a regression test without writing selectors

State the flow in plain language — sign in, add to cart, check out — and let the run figure out the elements.

02

Running the suite in CI

Execute the same natural-language tests headlessly as part of a workflow, rather than maintaining a parallel scripted suite.

03

Testing a flow behind a login

Sign in once in the managed Chrome profile and let later runs reuse that session; clear the profile when you want a clean state.

BEFORE YOU INSTALL

What to know first

Requires

Node.js 18+
Playwright's browsers, installed with npx playwright install
An OpenAI API key, passed as --api-key in the client config

INSTALLATION

Connect your client

Add the block to your client, or run the command directly.

Server setup

Configuration file

JSON

{
  "mcpServers": {
    "limetest": {
      "command": "npx",
      "args": [
        "@limetest/mcp",
        "--api-key=<YOUR_OPENAI_API_KEY>"
      ]
    }
  }
}

npm

TERMINAL

npm install @limetest/mcp

Limetest