Somebody else had a very similar issue:
https://steamhost.cn/steamcommunity_com/groups/BlenderSourceTools/discussions/1/1741100099549325267/?tscn=1542222034

It looks like you clicked the compile all button instead of the cube.qc button

this button "compiles all now" what does it do more that QC button ?
QC button create : mdl, phy, vdd, vtx
And in documentation "Compile all now" :
Does exactly what it says.
It's not very clear

Besides, for the .qc file there is an editor or a button for the generate one or it must be done manually?

(Briefly) The way a Valve Model work from idea to in game is:

1) create model in a 3d editor (Blender)

2) create an armature and assign mesh to it

3) UV unwarp the model and texture it

4) export SMD or DMX source files from blender

5) write the qc that will be used to compile the model into Binary model for use in game

6) click the button that is created when you point blender source tools at where the qc lives and
COMPILE the model into a Valve Binary model.
(A compiled model is made up of 3 to 8 files depending on the game being compiled for, these are the .mdl, .vtx files (the .sw.vtx, .dx80.vtx and .dx90.vtx), the .vvd file and the .phy (collision model) file.)
Only click the compile all button if there are more and one qc in the folder you pointed at and want to compile all qcs in one go.
(But it is always better to compile them one at a time by clicking their individual buttons. This way you catch errors faster and bttr if they occur)

7) Create Valve Material (vmt) and Texture (vtf) files

8) enjoy your model in game

As I said, this is a brief discription of the process. Each game you compile for has its own quips that you have to watch out for.

Ok then "Compile all" compile many differents .qc
And we have any generator for make .qc

QCs have to be written manually for each model you want to compile. There isn't an automaker for creating QCs