Cockroach Browser is an open-source, local-first browser runtime designed for AI agents. It provides complete Playwright and Puppeteer APIs across Chromium, Firefox, and WebKit, enabling cross-browser automation and agent control. With a built-in planner, semantic snapshots, mobile WebDriver, fleet adapters, and six SDKs, it offers a comprehensive toolkit for stateful web automation. It includes MCP support and verifiable evidence capture, making it ideal for QA, diagnostics, and AI-driven workflows. Free under AGPL-3.0, it's a powerful alternative for developers seeking a lightweight, flexible browser automation solution.