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NewsMaterial2 min readDisconfirmAI Editorial

Browser Use Co-founder Gregor Zunic Details Six Ways to Let Coding Agents Use Logged-In Chrome

Browser Use co-founder Gregor Zunic published a practical guide detailing six configuration methods for coding agents like Claude Code, Codex, Gemini CLI, and Cursor to use logged-in Chrome sessions, explaining why direct cookie copying fails.

Verified 2026-10-26 14:42 GMT+8

Coding agents often need to access logged-in web applications during development—for example, to test an admin interface that requires authentication. If an agent can only launch a fresh, unauthenticated browser instance, it cannot complete such tasks.

Gregor Zunic, co-founder of Browser Use, published a practical guide on October 25, 2026, systematically organizing six solutions for mainstream coding agents including Claude Code, Codex, Gemini CLI, and Cursor to reuse logged-in Chrome sessions. The article provides configuration steps for each agent and explains why the intuitive approach of directly copying browser cookies does not work.

Zunic points out that copying cookies into a fresh browser fails because the new browser is treated as a different device. With the adoption of Device Bound Session Credentials, Chrome stores private keys in secure hardware like TPMs; when short-lived session cookies expire, they can only be refreshed by proving possession of that key. Copied cookies on another machine cannot be renewed. Additionally, starting from Chrome 136, --remote-debugging-port and --remote-debugging-pipe are ignored on the default data directory; Google made this change because attackers were using remote debugging to steal cookies.

For Claude Code users, if subscribed to a Pro, Max, Team, or Enterprise plan, the shortest path is using Anthropic's Claude in Chrome extension via the claude --chrome command. If using an API key or another provider, one must switch to Browser Harness, Playwright MCP's extension mode, or Chrome DevTools MCP.

For Codex, OpenAI's browser extension can be used within the ChatGPT desktop app; in Codex CLI, Browser Harness or one of the two MCP servers is recommended. Gemini CLI ships with a built-in browser subagent that attaches to running Chrome by setting sessionMode to "existing" in settings.json. Cursor's built-in browser keeps its own workspace cookies; to use Chrome logins, one must add Browser Harness, Playwright MCP, or Chrome DevTools MCP to .cursor/mcp.json.

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Playwright MCP's extension mode allows users to select specific tabs accessible to the agent, suitable for scenarios where limiting agent permissions is desired. Chrome DevTools MCP's auto-connect mode (requiring Chrome 144+) provides full debugging capabilities, including performance traces and network request analysis. Browser Harness, as an open-source tool, attaches to the entire running browser via the Chrome DevTools Protocol, supporting multiple agent interfaces.

Zunic emphasizes security risks: an agent in a signed-in browser can do anything the user can, such as sending emails, changing settings, or buying things. Prompt injection is the main threat, which Anthropic calls "the biggest risk facing browser-using AI tools." He recommends using a separate Chrome profile whenever possible, avoiding letting the agent access sensitive accounts like banking, healthcare, and government, and turning off remote debugging when done.

Sources

  • browser-use.com↗
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