Eve

The Stagehand integration binds run, snapshot, and screenshot as native in-process Eve tools backed by one durable browser session, without starting an MCP server or bridge process. Eve is Vercel’s framework for building agents with Markdown instructions and skills, TypeScript tools, and durable execution.

Stagehand ships this experimental integration from the repository rather than publishing it as a standalone adapter.

Prerequisites

Node.js 24 or newer
pnpm 11.10.0
A model-provider credential for Eve
A current Google Chrome installation for local browser mode

Quickstart

Clone and build Stagehand

git clone https://github.com/browserbase/stagehand.git
cd stagehand
corepack pnpm@11.10.0 install --frozen-lockfile
corepack pnpm@11.10.0 exec turbo run build \
  --filter @browserbasehq/stagehand-integrations

Configure the Eve model

The example uses an OpenAI model by default:

export OPENAI_API_KEY="your-openai-api-key"

Set EVE_STAGEHAND_MODEL to select another Eve model.

Choose the browser

The example uses local Chrome by default. To use Browserbase instead:

export STAGEHAND_BROWSER="browserbase"
export BROWSERBASE_API_KEY="your-browserbase-api-key"

Start Eve

corepack pnpm@11.10.0 --dir packages/integrations/eve dev

Run a browser task

At Eve’s > terminal prompt, enter:

Open https://example.com and report the page title.

Eve uses the run tool and should report Example Domain before returning to the prompt.

Configuration

Variable	Purpose
`EVE_STAGEHAND_MODEL`	Eve agent model.
`OPENAI_API_KEY`	Credential for the example’s default Eve model.
`STAGEHAND_BROWSER`	Select `local` or `browserbase`.
`BROWSERBASE_API_KEY`	Required for Browserbase.
`BROWSERBASE_PROJECT_ID`	Optional Browserbase project ID.
`STAGEHAND_MODEL_NAME`	Optional model for Stagehand AI methods called inside `run`.
`STAGEHAND_MODEL_API_KEY`	Optional credential for `STAGEHAND_MODEL_NAME`; Eve can infer a supported provider key.
`STAGEHAND_EVE_SESSION_FILE`	Optional file where Eve persists a Browserbase session ID. Defaults to the system temporary directory.

Session lifecycle

One Eve world process owns one shared browser. Use this example for a single Eve session because concurrent sessions in the process share pages, authentication, and other browser state. On Browserbase, the example creates a keepAlive session and writes its ID to a temporary file. A process restart reattaches to the stored session instead of silently creating another one. Tool errors do not reset a healthy browser.

A Browserbase keep-alive session continues running and can continue billing until Eve reattaches it, you release it through Browserbase, or the project timeout ends it.

run executes model-authored JavaScript in the browser. For untrusted tasks, review the integration security boundary.

Eve integration source

Read the native tool bindings and durable-session implementation.

First steps

The basics

Configuration

Integrations

Best practices

Migration guide

SDK reference

Prerequisites

Quickstart

Configuration

Session lifecycle

Eve integration source

​Prerequisites

​Quickstart

​Configuration

​Session lifecycle

Eve integration source

Prerequisites

Quickstart

Configuration

Session lifecycle