gbasin Dev Browser
A CLI for controlling browsers with sandboxed JavaScript scripts.
Installation
npm install -g dev-browser
dev-browser install
Usage
Run dev-browser --help to learn more.
IMPORTANT: Avoid Permission Prompts
Never use heredocs (<<'EOF'), output redirection (2>/dev/null), or semicolons (;) in commands. These trigger "ambiguous syntax" permission prompts in Claude Code.
Instead, always write scripts to .dev-browser/ in the project root (the current working directory, not the skill directory) and run them with dev-browser run:
// .dev-browser/navigate.js
const page = await browser.getPage("main");
await page.goto("https://example.com");
await page.waitForSelector("body");
console.log(JSON.stringify({ title: await page.title(), url: page.url() }));
const buf = await page.screenshot();
await saveScreenshot(buf, "main.png");
dev-browser run .dev-browser/navigate.js
Use .js extension. Use short task-descriptive names (e.g., fill-login.js, scrape-prices.js). If a file exists that you didn't create, add a numeric suffix.
Sandbox Constraints
Scripts run in a QuickJS WASM sandbox, not Node.js:
- No
require()/import()— no module loading - No TypeScript — plain JavaScript only, everywhere (including
page.evaluate()) - No
fs,fetch,process— usesaveScreenshot(),writeFile(),readFile()for I/O (sandboxed to~/.dev-browser/tmp/)
The browser global is pre-connected. Screenshots must use saveScreenshot(buf, name) — not page.screenshot({ path }).