# Step 2: Design rules

Choose the fab and load its design rules before anything is drawn: the AI asks the human which fab builds the board (3rdPartyFab by default, JLCPCB on request) and loads that fab's rule profile into the EDA (KiCad .kicad_dru, Fusion DRC rules), so every later step designs to the process that will build it.

## Visits

- 2026-11-09T06:17:02Z (a return: re-record this step's proof on the final board (run.json outcomes were cleared by an accidental start --force; board and spec unchanged))
- 2026-11-10T04:11:01Z (a return: Rev B requested by the user: PCBWay bare board (hand-soldered), soldered MX switches instead of hotswap sockets, green mask, lead-free HASL)

## What the binary checked

### rules

- **kicad**: aiflow-run/rules/pcbway-2L.kicad_dru, aiflow-run/board-37.kicad_dru
- **layers**: 2
- **native**: eda kicad
- **profile**: pcbway
- **slug**: pcbway

## Screenshots and drawings

**start**

![start](shot-rules-1-start.png)

**end**

![end](shot-rules-1-end.png)

**start**

![start](shot-rules-2-start.png)

**visit 1-end**

![visit 1-end](shot-rules-1-end.png)

**visit 1-start**

![visit 1-start](shot-rules-1-start.png)

**visit 2-start**

![visit 2-start](shot-rules-2-start.png)

## Clips

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