# unbrowser by Unchained

Stateful web runtime for agents without Chrome: keeps cookies, returns DOM element refs and page signals.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 16
- Author: protostatis
- License: Apache-2.0 · policy=link-only · description only; the file stays with the author
- Source: https://github.com/protostatis/unbrowser
- Updated: 2026-08-21
- HTML: https://affpapa.org/en/nevibecode/mcp/unbrowser-by-unchained

## What it does

The server sits between `curl` and a full browser. It retains session state, processes forms and redirects, returns a structured page map with headings, landmarks and interactive elements. The agent gets stable node references like `e:142` — click or fill a field without re-parsing HTML.

Default `navigate` is a fast static pass. Set `exec_scripts: true` to run light scripts in QuickJS under a watchdog. This is not V8 or a rendering engine: heavy SPAs, Canvas, WebGL and extensions need real Chrome. The server detects challenges and thin shells, returns `thin_shell` and `challenge.provider` signals — the agent knows when to escalate.

Installing via `pip` requires Python 3.10+. On macOS, the built-in `/usr/bin/python3` is version 3.9 and won't work: use `pipx` or Homebrew Python instead.

## Requirements
- Needs: Python and uv (commands run via uvx)

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add unbrowser -- uvx pyunbrowser
```
uvx runs the command named after the package; if the README names another one, use uvx --from pyunbrowser <command>

### Codex

**Platform CLI**
```bash
codex mcp add unbrowser-by-unchained -- uvx pyunbrowser
```
uvx runs the command named after the package; if the README names another one, use uvx --from pyunbrowser <command>

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "unbrowser-by-unchained": {
            "command": "uvx",
            "args": [
                "pyunbrowser"
            ]
        }
    }
}
```
uvx runs the command named after the package; if the README names another one, use uvx --from pyunbrowser <command>

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "unbrowser-by-unchained": {
            "type": "stdio",
            "command": "uvx",
            "args": [
                "pyunbrowser"
            ]
        }
    }
}
```
uvx runs the command named after the package; if the README names another one, use uvx --from pyunbrowser <command>

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add unbrowser-by-unchained uvx pyunbrowser
```
uvx runs the command named after the package; if the README names another one, use uvx --from pyunbrowser <command>

## When to use it
- navigate static HTML pages while keeping cookies between requests
- extract data by selector and get a stable element reference
- submit a form and follow the redirect
- detect whether a page needs a real browser
- run light hydration in QuickJS without Chrome

## Example prompts
- Navigate to `https://news.ycombinator.com` and show the first five links from `.titleline > a`
- Fill the `#email` field at `example.com/contact` and submit the form
- Check if `site.com` needs a full browser or a static pass is enough

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md