```coffeescript
Client = require 'librato'

module.exports = new Client \
  process.env.LIBRATO_USER, \
  process.env.LIBRATO_TOKEN, \
  prefix: process.env.LIBRATO_PREFIX, source: process.env.DOTCLOUD_SERVICE_ID

```

Add default Librato source as "test"
user
```coffeescript
Client = require 'librato'

module.exports = new Client \
  process.env.LIBRATO_USER, \
  process.env.LIBRATO_TOKEN, \
  prefix: process.env.LIBRATO_PREFIX, source: process.env.DOTCLOUD_SERVICE_ID or 'test'

```
assistant