Insert points in tetgen

[clockwork85]

I'm having trouble with the insert_points flag in tetgen. It is working using the corresponding cube.poly with a cube.a.node file. In meshpy I have:

from meshpy.tet import MeshInfo, build
import numpy as np

# Define the original set of points
points = [
    (0, 0, 0),
    (1, 0, 0),
    (1, 1, 0),
    (0, 1, 0),
    (0, 0, 1),
    (1, 0, 1),
    (1, 1, 1),
    (0, 1, 1)
]

# Define the facets (tetrahedral elements)
facets = [
    [0, 1, 2, 3],
    [4, 5, 6, 7],
    [0, 4, 5, 1],
    [1, 5, 6, 2],
    [2, 6, 7, 3],
    [3, 7, 4, 0]
]

info = MeshInfo()
info.set_points(points)
info.set_facets(facets)

additional_points = [
    (0, 0, 0.5),
    (0, 1, 0.5),
    (1, 1, 0.5),
    (0, 1, 0.5)
]
additional_info = MeshInfo()
additional_info.set_points(additional_points)

mesh = build(info, insert_points=additional_info, verbose=True)
print(f"{np.array(mesh.points)=}")

# np.array(mesh.points)=array([[0., 0., 0.],
#       [1., 0., 0.],
#       [1., 1., 0.],
#      [0., 1., 0.],
#       [0., 0., 1.],
#       [1., 0., 1.],
#       [1., 1., 1.],
#       [0., 1., 1.]])

I've tried creating using options=Options("pqAai")

If I use these inputs I get the correct result:

# cube.poly
8 3 0 0 
1  0 0 0 
2  1 0 0 
3  1 1 0 
4  0 1 0 
5  0 0 1  
6  1 0 1 
7  1 1 1 
8  0 1 1 

6 0
1 
4 1 2 3 4
1  
4 5 6 7 8 
1 
4 1 5 6 2
1 
4 2 6 7 3
1  
4 3 7 8 4
1 
4 4 8 5 1

#  hole list
0

#  region list
0

#cube.a.node
4 3 0 0
1 0 0 0.5 
2 1 0 0.5 
3 1 1 0.5 
4 0 1 0.5 

#cube.1.node results have the 0.5 nodes
12  3  0  0
   1    0  0  0
   2    1  0  0
   3    1  1  0
   4    0  1  0
   5    0  0  1
   6    1  0  1
   7    1  1  1
   8    0  1  1
   9    0  0  0.5
  10    1  0  0.5
  11    1  1  0.5
  12    0  1  0.5
# Generated by tetgen -pqAai cube.poly 

I also tried just an interior node (0.5, 0.5, 0.5) in meshpy and it seems to ignore it as well, so it seems I'm not setting this up correctly. I checked the test/ and the examples/ and didn't find anything there to give me the correct method. Does anyone see where I'm going wrong?

Thanks!