Modulor — agent-native CAD

You drive CAD through JSON commands. One document = one .json file.

Setup check

modulor ops >/dev/null || pip install modulor

Core workflow

1. Run command batches (atomic — all succeed or nothing is saved):

modulor run model.json - <<'EOF'
[{"op":"add_wall","path":[[0,0],[8000,0],[8000,5000],[0,5000],[0,0]],
  "thickness":240,"height":2900,"tag":"ext"},
 {"op":"add_opening","wall":{"tags":["ext"]},"along":1500,"width":1000,"type":"door"},
 {"op":"render","path":"check.png","mode":"plan"}]
EOF

1. Look at what you made: render writes a PNG — read it. Add

"labels": true to print entity ids on the image.

1. Verify numerically: {"op":"measure","kind":"area","select":...},

{"op":"validate"}, {"op":"find","at":[x,y],"radius":r}.

1. Export: .dxf .svg (drawings) · .glb .stl .obj (meshes) ·

.ifc (semantic BIM for Revit) — via {"op":"export","path":"out.ifc"}.

Rules that prevent 90% of mistakes

• Discover, don't guess: modulor ops <name> gives every param + example.
• Prefer tag + {"tags":[...]} selectors over hardcoded ids — booleans

consume entities and ids go stale.

• Numeric fields accept expressions: "bay*3", "level_top('L2')",

"grid_x('B')" (params via define_param, levels via add_level, grids via add_grid).

• Z is up; angles are degrees CCW; units default to mm.
• Errors are structured JSON with a hint — read it, fix, resend the batch.
• Parametric design: store the script with

{"op":"recipe_set","commands":[...],"run":true}, then {"op":"regenerate","params":{"bay":5000}} rebuilds everything coordinated.

• Before risky edits: {"op":"snapshot","name":"safe"}; roll back with

restore; compare options with {"op":"diff","against":"safe"}.

Taking over existing drawings

{"op":"import_dxf","path":"site.dxf"} reads real-world DXF (blocks, hatches, GBK text). Then render with labels, inspect with find, rebuild semantics with add_wall/add_room where needed.

Showing the human

Suggest they run modulor serve model.json — a read-only browser viewer that live-follows the document while you work.

Full reference: run modulor ops, or read AGENT_GUIDE.md in the Modulor repository (github.com/bcllcc/modulor).