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Eve is a framework for building durable agents. The @browserbasehq/eve extension gives an Eve agent browsers that work where APIs can’t. The extension starts with Browserbase Search and Fetch for lightweight discovery and retrieval. When a page requires JavaScript or interaction, your agent can use Stagehand with a persistent Browserbase browser.

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How it works

The extension adds these tools to your Eve agent: Use Search, then Fetch, then a browser as an escalation path. This approach reserves browser sessions for pages that need them.

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Persistent browser sessions

The extension stores the Browserbase session ID in Eve’s durable per-session state. Each browser tool reconnects to the same browser, performs its operation, and disconnects without ending the session. This lets your agent keep browser state across Eve workflow steps and Vercel function invocations. Call stop_session when your agent finishes its task to stop billable browser time. Keep-alive availability depends on your Browserbase plan.

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Model access

Stagehand uses Browserbase Model Gateway for browser inference, so one Browserbase API key covers the browser and Stagehand. The outer Eve agent uses Vercel AI Gateway through an AI_GATEWAY_API_KEY or a linked Vercel project’s VERCEL_OIDC_TOKEN.

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Get started

Quickstart

Add the Browserbase extension to an Eve agent and run your first browser task.

Example source

Browse the complete Eve agent example on GitHub.