Chrome Relay Lets AI Agents Use Your Signed-In Chrome Tabs

Summary

Chrome Relay is an open-source macOS and Chrome tool that lets Claude Code, Codex, Cursor, and Paseo operate background tabs in the user’s existing Chrome profiles through a command-line interface. It addresses four requirements: CLI access, existing signed-in sessions, no browser focus interruptions, and fast page operations. A local relay on 127.0.0.1:9333 connects an agent’s WebSocket DevTools endpoint to a Manifest V3 extension, which uses Chrome’s debugger API to control inactive tabs grouped under “Agents.” The design avoids Chrome’s remote-debugging prompt and prevents agents from seeing tabs opened by other agents. The relay assigns per-agent endpoints, handles popups and OAuth flows, and can continue Google sign-in when the correct account is already available; it stops when a password, passkey, or two-step verification screen appears. The author reports command latency of about 0.15 seconds and page-open latency of about 0.6 seconds. Access requires a machine-specific secret plus verification that the client is one of the supported agent processes, while the extension connection must originate from the author’s own extension and Chrome. These checks are intended to prevent accidental access, but do not protect against malware already running as the user. Actions are recorded in an audit log, with typed text stored only as a length. The project currently supports macOS and Chrome, requires Node.js 20 or later and agent-browser, and is released under the MIT license.