> ## Documentation Index
> Fetch the complete documentation index at: https://docs.browspark.krishm.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# CLI and environment

> Flags, environment variables, scripts and what the companion prints.

## Entry point

```bash theme={null}
bunx browspark-mcp@latest [--port <n>] [--http-only]
```

or the compiled `dist/browspark` with the same flags.

| Flag          | Effect                                                                                                                  |
| ------------- | ----------------------------------------------------------------------------------------------------------------------- |
| `--port <n>`  | Listen on this port instead of `9223` for the extension bridge, the HTTP MCP endpoint and the live view.                |
| `--http-only` | Do not connect MCP over stdio and do not exit when stdin closes. For URL-based clients when no stdio client is running. |

## Environment variables

| Variable              | Default                  | Purpose                                                                         |
| --------------------- | ------------------------ | ------------------------------------------------------------------------------- |
| `BROWSPARK_PORT`      | `9223`                   | Same as `--port`.                                                               |
| `BROWSPARK_CHROME`    | auto-detected            | Browser executable for developer mode.                                          |
| `BROWSPARK_PROFILE`   | `~/.browspark/profile`   | Profile directory of the `default` developer context.                           |
| `BROWSPARK_PROFILES`  | `~/.browspark/profiles`  | Parent directory of named developer contexts.                                   |
| `BROWSPARK_ARTIFACTS` | `~/.browspark/artifacts` | Output directory for traces, profiles, snapshots, HAR, PDFs, reports and flows. |

Recorder exports read flow parameters from environment variables named after the parameter in upper case (`{{email}}` → `EMAIL`).

## Package scripts

| Script                 | What it does                                                                            |
| ---------------------- | --------------------------------------------------------------------------------------- |
| `bun run build`        | Bundle the extension's service worker and dashboard into `extension/dist/`.             |
| `bun run package`      | Build and zip the extension to `dist/browspark-extension.zip`.                          |
| `bun run compile`      | Single-file companion binary at `dist/browspark`.                                       |
| `bun run start`        | Run the companion from source.                                                          |
| `bun run typecheck`    | Type-check companion and extension.                                                     |
| `bun test`             | Unit and bridge tests (no browser).                                                     |
| `bun run test:e2e`     | Launch throwaway Chromes and run every acceptance scenario.                             |
| `bun run capabilities` | Regenerate the [capability matrix](/reference/capability-matrix) by probing both modes. |
| `bun run docs:tools`   | Regenerate the tool reference pages and their navigation from the tool registrations.   |

## What the companion prints

Everything goes to stderr, because stdout is the MCP stdio channel.

```text theme={null}
browspark: ready on ws://127.0.0.1:9223 (pairing token a1b2c3d4); MCP over HTTP at http://127.0.0.1:9223/mcp?token=a1b2c3d4
browspark: extension connected
browspark: 2 tool(s) disabled from the dashboard; developer browser: auto
browspark: agent connected: claude-code
browspark: http client session 5f1e9c0a
browspark: relaying stdio to the companion already running on port 9223
browspark: agent disconnected: claude-code
browspark: extension disconnected
```

## Exit behaviour

The companion exits when stdin closes (the stdio client went away), on `SIGINT` or `SIGTERM`. On exit it closes the bridge and every developer browser it launched. Relays exit when their stdin closes or when the owner they relay to stops answering.