What does the 'tool will cut through material' warning mean, and is it bad?

What it means

The toolpath's total cut depth is greater than or equal to the material thickness set in Job Setup. The software flags it so you can decide whether that is intentional.

When it's expected (say OK)

Cut-out and through-cut profiles. Standard practice is cutting slightly past the material thickness, a small overcut into the spoilboard (for example, 0.2 to 0.5 mm, or 0.01 to 0.02"), to guarantee full separation even where the board runs a hair thick. If you set that up deliberately, the warning is just confirming it.

When it's a red flag (stop and check)

• You did not intend a through cut. A pocket or V-carve showing this warning means a depth typo or a Start Depth stacking error (see the Start Depth entry).
• The material thickness in Job Setup is wrong. Measure the actual board. A 0.75" setup on 0.70" stock makes every through-cut plow 0.05" deeper into your spoilboard than planned.
• Your Z-zero convention doesn't match (see the Z-zero mismatch entry). The warning may be the only symptom you get before cutting.

Pro tips

• Keep overcut modest: deep spoilboard scoring wastes spoilboard flatness and dulls bits on MDF glue.
• When tabs are in use, remember that tab thickness is measured from the bottom of the cut depth, so it must exceed the overcut or the tabs vanish (see the tabs entry).