Call Subroutine withTool Change T Code And M6 Code

There is some documentation here:
linuxcnc.org/docs/2.7/html/remap/remap.h...lated_codes_t_m6_m61

Also take a look at the configs here:
github.com/LinuxCNC/linuxcnc/tree/master...smach/VMC_toolchange

This line in the INI file:
github.com/LinuxCNC/linuxcnc/blob/master...ge/vmc_index.ini#L21
makes the system call the toolchange.ngc G-code file.

You might be able to leave out the change_prolog and change_epilog parts, depending on what your toolchange routine needs to know.
toplevel.py is automatically loaded by remap. All that does is say where the remapped Python code is.
In this case, remap.py. This just loads the built-in "stdglue.py" file which sets some handy G-code parameters:
#<tool_in_spindle>
#<selected_tool>
#<current_pocket>
#<selected_pocket>
These files are standard, you can add them to your configuration as-is. Or you can not bother with them and not mention the change_prolog and change_epilog in the REMAP line, if you don't need the extra info that they provide in G-code parameters.