EntEd

EntEd is a tool that can view and edit the entity properties of a BSP file similar to Entspy.The program is useful for tweaking small entity properties without compile the map again.

EntEd is a tool that can view and edit the entity properties of a BSP file similar to Entspy. The program is useful for tweaking small entity properties without compile the map again.

The EntEd interface.

Source: https://developer.valvesoftware.com/wiki/EntEd