Route a board

Route by hand, net by net, after placement (kicad-placement), with board.py (kicad-board-edit): connect, track, via, gnd_via and zone. Run DRC (printed on every save) until nothing is unconnected.

Rules and net classes

These live in the .kicad_pro JSON; edit it only while the PCB editor is closed.

• Setting them: board.py rules writes the fab's minimums, the Default class and a Power class; set_rules(pro, classes={...}) adds others. connect and track take their width from the net's class.
• Classes: net_settings.classes, each with name, track_width, clearance, via_diameter, via_drill and priority (lower wins).
• Assigning nets: net_settings.netclass_patterns entries such as {"netclass": "Power", "pattern": "+5V"}. Patterns match the board's net names exactly (/VBUS) and accept wildcards (/USB_D*).
• Minimums: board.design_settings.rules (min_clearance, min_track_width, …), at or above the fab's limits.

DRC enforces a class's clearance but not its track width. Where width matters, add a rule to <board>.kicad_dru (comments on their own lines):