Samsung Companion App: Do we need Samsung Gear App on Phone?

I am new to Tizen development. I am developing companion apps for Samsung gear watch(provider) and Android phone(Consumer). I have few questions regarding it

1. Does my app need Samsung gear app to be installed on phone?
2. If yes, is there a way to find whether Gear app is installed or not?

1. an application can run independently on the watch even if the companion is not installed. An application can run on the phone independently of whether or not the watch app is installed. Whether or not the application remains functional in the absence of the other agent is going to be up to your application design. You do need to have the Samsung Gear Manager application installed. On Samsung phones the phone will generally automatically direct a user to install the app upon pairing with the watch. On Android applications they'll need to grab it from the App store.
2. The easiest way to check is to try to connect to it (findPeerAgent). If it's not installed you won't be able to find a the peer agent.

While not part of your question some have wanted to know if a phone is even paired with a watch. If it is the watch will be listed as a paired bluetooth device from getBondedDevices(). But I'm not sure what set of attributes on the Bluetooth devices returned need to be queried to determine if a particular device is a Gear watch. Note that this method will return a device even if the watch were turned off or disconnected for some other reason at the time the method is called.