> ## Documentation Index
> Fetch the complete documentation index at: https://docs.webrayn.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> A portable, LLM-driven browser-automation & web-scraping MCP server — one binary, three engines, any OS.

# What is webrain?

**webrain** is a portable, LLM-driven browser-automation and web-scraping **MCP
server** — one binary, three browser engines, any OS. It exposes **51 tools**
over the Model Context Protocol. Install it on any system, point any LLM client
(GitHub Copilot, Claude, Codex, Cursor, …) at it, and the model decides
everything — search, crawl, scrape, navigate, interact — from a plain-language
prompt. No hardcoded intent detection, no daemon, no Node.js.

## Why webrain?

Web automation shouldn't mean wiring up a driver, a browser download, and your
own tool wrappers before an LLM can touch a page. Webrain collapses that into
**one binary + one install command** and speaks MCP, so any LLM client drives
it directly.

<Card title="Quickstart" icon="rocket" href="/quickstart">
  Get a browser engine, start the MCP server, and drive it from a prompt in minutes.
</Card>

## What you can do with it

* **Scrape at scale** — batch pagination + spider with auto-throttle and
  checkpoint/resume; `webrain_sitemap` / `webrain_scan` to map a site first.
* **Structured data without hand-written selectors** — `webrain_autoschema`
  probes the DOM, then JSON / regex / table extractors read container-level
  structure.
* **Stealth login** — real-Chrome profiles with an encrypted local credential
  vault (AES-256-GCM + optional TOTP); transfer cookies across engines.
* **Get past challenges** — reads the `challenge` field on every navigate and
  solves Cloudflare/Turnstile via a real-Chrome stealth sidecar.
* **See the page** — a11y / semantic tree, snapshots, and vision tiles
  (screenshot → vector store) for tables and charts.
* **Read anything** — PDFs (extract + render), JSON-LD, media, plus
  `fetch_http` for static pages 10–100× faster than a browser.

## How it's built

| Layer    | Crate          | Responsibility                                                 |
| -------- | -------------- | -------------------------------------------------------------- |
| Core     | `webrain-core` | CDP client, engines, vault, launch, install, vision            |
| Protocol | `webrain-mcp`  | MCP server: `list_tools` / `call_tool`, tool schemas           |
| Entry    | `webrain-cli`  | Single binary — `mcp` \| `install` \| `launch` \| `login` \| … |

Everything speaks **Chrome DevTools Protocol** over a raw WebSocket, so one
backend drives Chrome, Lightpanda, and Obscura interchangeably.

## Prerequisites

* **OS**: Windows, macOS, or Linux (x86\_64 / arm64).
* **A browser engine** — run `webrain install` once (downloads Chrome for Testing). Obscura and Lightpanda are optional extra engines.
* **Linux**: system libraries for Chrome — see [Installation](/installation).
* **Python 3** — only for the stealth sidecar (`scripts/stealth_solve.py`) to bypass Cloudflare/Turnstile challenges.
* **Docker** — only to run the obscura / lightpanda engines in containers.
* **An MCP-capable client** (VS Code + Copilot, Claude, Codex, Cursor, …) — optional; the CLI works standalone.

## Where to go next

* [Installation](/installation) — every install path, one-liners included
* [Agent Decision Guide](/concepts/browsers) — which browser, how to handle a challenge, which extractor
* [Tools Reference](/reference/tools) — the full 51-tool surface
* [CLI Reference](/reference/cli) — drive webrain by hand