LangChain Managed Deep Agents Add Browser Use with 90% WebVoyager Pass Rate

Details

LangChain Managed Deep Agents now includes managed browser capabilities, allowing agents to perform web tasks like booking and form-filling without user-managed infrastructure.
On 100 tasks from the WebVoyager benchmark, the new browser tools achieved a 90% pass rate at a total cost of $1.98, the highest among seven tested toolsets.
The closest competitor, Browserbase's MCP server, achieved an 89% pass rate but at 9x the cost.
Browser sessions support thread and user scopes, with user scope allowing login credentials to persist across different agent threads.
A browser_handoff feature allows users to take over the browser for sensitive actions like logging in, then return control to the agent.
The tools are built on Stagehand, Browserbase's open-source SDK, and use a browser_run tool that accepts code to batch actions, keeping page content out of the agent's context to improve efficiency.
End-to-end testing is supported via a private localhost bridge that connects the remote browser to the agent's sandbox, enabling testing of local apps without public URLs.

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