Contributing to Stagehand

Stagehand is open source under the MIT license. This guide covers the parts of the repository a contributor needs: how the packages fit together, how to run the checks, and what a change has to carry before it can be released.

Where to start

Browserbase prioritizes reliability, extensibility, speed, and cost, in that order. Bug fixes and small improvements are the best way to get started.

For anything larger, raise it in Discord first. A quick conversation is the best way to confirm the direction fits the roadmap before you invest time in building it.

How the repository fits together

Stagehand runs in two halves. The SDK runs in your process and holds the browser handle. The runtime that executes act(), extract(), and observe() ships as a Chrome extension and runs inside the browser. The two talk over the Chrome DevTools Protocol, with a JSON-RPC protocol tunneled through it.

That protocol is the contract, and it decides how a change ripples through the repository:

Package	What it is
packages/protocol	The JSON-RPC contract. The source of truth for every client
packages/extension	The in-browser runtime that serves those methods
packages/sdk-ts	The TypeScript SDK, published to npm as @browserbasehq/stagehand. Consumes the protocol schemas directly
packages/sdk-python	The Python SDK, published to PyPI as stagehand. Its models are generated from the protocol
packages/sdk-go	The Go SDK. Its models are generated from the protocol, and it is released by module tag
packages/evals	The evaluation harness
packages/docs	The documentation site

Because Python and Go are generated, a protocol change is never a single-package change. Regenerate the clients rather than hand-editing anything under packages/sdk-python/src/stagehand/_generated/ or a *.gen.go file.

Set up your environment

Stagehand is a TypeScript, Python, and Go monorepo, and just drives all three. Install Node.js 22.18 or later, Go 1.26, just, pnpm, and uv. Go first.

git clone https://github.com/browserbase/stagehand.git
cd stagehand
just install
just build

just install installs the pnpm workspace, syncs the Python environment with uv, and downloads the Go modules. pnpm install on its own covers only the TypeScript workspace, which leaves the Python and Go checks unable to run.

Add an LLM provider key and a Browserbase API key to run anything that reaches a model or a cloud browser:

cp .env.example .env

Run an example to confirm the setup works:

just example act        # packages/sdk-ts/examples/act.ts
just go-example act     # packages/sdk-go/examples/act.go

Before you open a pull request

Run these from the repository root. Each covers TypeScript, Python, and Go together, which is what CI runs:

just fmt   # oxfmt, ruff, and gofmt
just check # formatting, lint, types, generated-code drift, and go vet
just test  # vitest, pytest, and go test

just check validates generated clients against the committed protocol schema. If you touched packages/protocol, regenerate first:

just generate

That rebuilds the protocol, regenerates the Python models and the Go client, and rebuilds the extension bundle. Commit the regenerated files with your change.

Changing the protocol

Adding or changing a method touches the schema, the extension that serves it, and every client that calls it. packages/protocol/README.md walks through that sequence, and runtime protocol versions covers the compatibility rule and the SemVer policy the table below depends on.

Stacked pull requests

Larger work in this repository usually lands as a stack. Target each pull request at its immediate predecessor rather than at main, and when a parent changes, merge it into its immediate child and resolve conflicts there. After a parent is squash-merged, verify that the child contains the parent's final tip before pushing again.

Versioning

Package metadata is the source of truth for versions. Each package can be selected independently in a Changeset; there are no fixed groups. The private Python package.json lets Changesets version the public stagehand package, and release tooling copies that version into pyproject.toml and uv.lock.

After the initial v4 release, run just changeset when a pull request changes a public SDK, the extension, or the protocol compatibility contract. Select only the packages intended for release and commit the generated .changeset/*.md file with the pull request. Tests, documentation, formatting, and internal refactors do not need a Changeset.

Change	Changeset
SDK-only fix or feature	Patch or minor for that SDK only
Extension-only implementation fix	Extension patch, plus each SDK that should ship it; no protocol bump
Compatible protocol correction requiring no new capability	Protocol patch, plus affected implementations as needed
Backward-compatible capability that a new client may require	Protocol minor, plus affected implementations as needed
Breaking wire or transport change	Protocol major and a coordinated release

Releases

Merging a normal pull request does not publish anything. Changesets creates or updates a release pull request on main, where further Changesets accumulate. When a maintainer is ready, merging that release pull request publishes a changed TypeScript SDK to npm and a changed Python SDK to PyPI.

TypeScript and Python do not have to be bumped together. The Python version stays in sync only with its own pyproject.toml and lockfile.

Two consequences are worth knowing before you plan a change:

• The extension is embedded in each SDK rather than published separately, so an SDK release is what delivers an extension fix to users.
• The release workflow does not create Go module tags. A Go release is tagged separately, with the version from packages/sdk-go/package.json.

The protocol package is versioned for compatibility tracking and is never published.

Preview builds

Add the preview label to a pull request to build the TypeScript package, the Python wheel, and the extension ZIP without publishing them. The workflow keeps one authenticated artifact and one comment up to date with the pull request. Artifacts expire after 30 days, so push a commit or remove and reapply the label to refresh one. Removing the label or closing the pull request removes both.

Previews do not change committed versions or changelogs, publish a release, or deploy a Browserbase environment.