This repository is a TypeScript monorepo for an AI-powered autonomous web browsing agent called 'open-browser'. It consists of three packages: core library (open-browser), CLI (@open-browser/cli), and sandbox (@open-browser/sandbox). The core library orchestrates an agent loop that uses Playwright to control a Chromium browser, extracts DOM state via CDP, sends it to an LLM (OpenAI, Anthropic, Google) which decides actions in structured JSON, and executes those actions via a CommandExecutor. The system supports vision screenshots, extended thinking, compact mode, planning, evaluation, replay recording, and MCP server integration. The CLI provides commands for running agents, interactive sessions, and direct browser manipulation. The sandbox provides resource-limited execution. Key entry points include the Agent class, Viewport browser session, CommandExecutor, and BridgeServer. External dependencies include Playwright, Vercel AI SDK, Zod, Turndown, and various LLM provider SDKs. The architecture follows a modular monorepo with clear separation of concerns, event-driven communication via EventHub, and a guard/watchdog pattern for browser lifecycle management. The codebase demonstrates strong engineering practices with extensive use of Zod schemas for structured outputs, a command catalog pattern, and comprehensive telemetry and cost tracking.