Long Horizon
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Getting Started

This guide walks you through connecting your first project to Long Horizon and running your first test. By the end, your AI coding agent will be able to execute browser tests against your application.

Step 1: Select your workspace

When you first open Long Horizon, you'll be prompted to select or create a workspace. A workspace is your team's shared environment—it determines who can access your test reports and project settings.

  • Personal workspace: Great for solo projects or trying things out
  • Team workspace: Share reports and collaborate with your team

You can switch workspaces anytime from the workspace selector in the bottom-left corner. See Workspaces for more details.

Step 2: Choose local mode

After login and workspace selection, Long Horizon asks whether to enable Local mode. Local mode stores session data on your device and disables sharing/hosted reports.

In both modes, your source code is never sent to Long Horizon servers. You can change this setting later in Settings.

See Local Mode for full details.

Step 3: Open your project

Click Open Project and select your repository's root folder—the directory containing your frontend application. Long Horizon will create a configuration folder to store project settings. It will also install the necessary skills and subagents to write and run tests.

Step 4: Configure your app URL

Enter the URL where your application runs during development. This is typically your local dev server:

http://localhost:3000

Long Horizon will open this URL in a real browser when running tests. Make sure the URL matches exactly where your app is served—wrong ports or protocols will cause tests to fail.

Step 5: Enable MCP in your coding agent

Long Horizon communicates with your AI coding agent through the Model Context Protocol (MCP). During onboarding, Long Horizon will configure MCP for your installed agents automatically.

For Cursor: Open Settings → Tools & MCPs and enable the Long Horizon server.

For Claude Code or Codex: Restart the CLI to pick up the new configuration.

See MCP Server for detailed setup instructions.

Step 6: Run your first test

  1. Start your development server as you normally would
  2. Make sure Long Horizon is running with your project open
  3. In your coding agent, ask it to test something using the lh-testing skill: /lh-testing Test that the login form shows an error for invalid credentials
  4. Watch as Long Horizon opens a browser and executes the test

What's next?