Python syntax

execute_code runs Python inside Parashell’s FreeCAD-compatible interpreter. The snippet is not shell code. It is not a package manager. It is not a general automation sandbox.

Allowed imports

Prefer only modules native to the CAD environment and the Python standard library for simple math/data handling:

import FreeCAD
import FreeCADGui
import Part
import Sketcher
import Draft
import Mesh
import TechDraw
import Spreadsheet
import math
from math import sin, cos, radians

Use optional workbench modules only when installed:

try:
    import Arch
except Exception:
    Arch = None

Do not import network, shell, package installation, or broad filesystem modules for modeling snippets.

Forbidden forms

Do not use these in execute_code:

import os
import subprocess
import socket
import urllib.request
import requests
import pathlib
open("/restricted/path", "w")
eval(user_text)
exec(user_text)
__import__(user_text)

Allowed file interaction is limited to Parashell document save/export APIs or explicit export paths requested by the user.

Literals

name = "Bracket"
count = 6
diameter = 12.5
enabled = True
missing = None
point = (0.0, 0.0, 0.0)
items = ["BoltA", "BoltB"]
props = {"Length": 40, "Width": 20}

Flow control

if doc is None:
    doc = FreeCAD.newDocument("Model")
else:
    doc.recompute()

for obj in doc.Objects:
    if hasattr(obj, "Shape") and not obj.Shape.isNull():
        pass

while False:
    pass

Avoid unbounded loops. Iteration counts must be small and deterministic.

Functions

Use local helper functions to remove repetition when the snippet remains short:

def vec(x, y, z=0):
    return FreeCAD.Vector(float(x), float(y), float(z))

base = vec(0, 0, 0)

Do not define large frameworks, persistent hooks, background timers, monkey patches, or module-level state intended to survive the operation.

Exceptions

Catch expected modeling failures and return a useful error. Do not swallow all failures silently.

try:
    doc.recompute()
except Exception as exc:
    raise RuntimeError(f"recompute failed: {exc}")

Comprehensions

solid_names = [
    obj.Name
    for obj in doc.Objects
    if hasattr(obj, "Shape") and obj.Shape is not None and not obj.Shape.isNull()
]

Keep comprehensions readable. Prefer ordinary loops when side effects are involved.

Attribute and property syntax

obj.Length = 40
obj.Width = 20
obj.Height = 10
obj.Label = "Base plate"
obj.ViewObject.Visibility = True
obj.ViewObject.ShapeColor = (0.8, 0.8, 0.8, 1.0)

Check property existence when assigning uncommon fields:

if "Length" in obj.PropertiesList:
    obj.Length = 40

Expressions

Use expressions to bind feature dimensions to spreadsheet aliases:

pad.Length = 1
pad.setExpression("Length", "Spreadsheet.PlateThickness")

Avoid hard-coding driving dimensions when a spreadsheet variable should control the model.

Minimal snippet structure

import FreeCAD
import Part

doc = FreeCAD.ActiveDocument
if doc is None:
    doc = FreeCAD.newDocument("Model")

obj = doc.addObject("Part::Box", "Block")
obj.Length = 40
obj.Width = 20
obj.Height = 10

doc.recompute()

Minimal parametric snippet structure

import FreeCAD
import Sketcher
import Part

doc = FreeCAD.ActiveDocument
if doc is None:
    doc = FreeCAD.newDocument("Model")

sheet = doc.addObject("Spreadsheet::Sheet", "Spreadsheet")
sheet.set("A1", "Length")
sheet.set("B1", "40 mm")
sheet.setAlias("B1", "Length")
sheet.set("A2", "Width")
sheet.set("B2", "20 mm")
sheet.setAlias("B2", "Width")
sheet.set("A3", "Thickness")
sheet.set("B3", "6 mm")
sheet.setAlias("B3", "Thickness")

body = doc.addObject("PartDesign::Body", "PlateBody")
sketch = body.newObject("Sketcher::SketchObject", "PlateSketch")
sketch.addGeometry(Part.LineSegment(FreeCAD.Vector(0, 0, 0), FreeCAD.Vector(40, 0, 0)), False)
sketch.addGeometry(Part.LineSegment(FreeCAD.Vector(40, 0, 0), FreeCAD.Vector(40, 20, 0)), False)
sketch.addGeometry(Part.LineSegment(FreeCAD.Vector(40, 20, 0), FreeCAD.Vector(0, 20, 0)), False)
sketch.addGeometry(Part.LineSegment(FreeCAD.Vector(0, 20, 0), FreeCAD.Vector(0, 0, 0)), False)
sketch.addConstraint(Sketcher.Constraint("Coincident", 0, 2, 1, 1))
sketch.addConstraint(Sketcher.Constraint("Coincident", 1, 2, 2, 1))
sketch.addConstraint(Sketcher.Constraint("Coincident", 2, 2, 3, 1))
sketch.addConstraint(Sketcher.Constraint("Coincident", 3, 2, 0, 1))
sketch.addConstraint(Sketcher.Constraint("Horizontal", 0))
sketch.addConstraint(Sketcher.Constraint("Vertical", 1))
sketch.addConstraint(Sketcher.Constraint("DistanceX", 0, 1, 0, 2, 40))
sketch.addConstraint(Sketcher.Constraint("DistanceY", 1, 1, 1, 2, 20))

pad = body.newObject("PartDesign::Pad", "PlatePad")
pad.Profile = sketch
pad.Length = 6
pad.setExpression("Length", "Spreadsheet.Thickness")
body.Tip = pad

doc.recompute()

When possible, use the structured MCP sketch and spreadsheet tools instead of writing this by hand.

Agent Reference

MCP Tools

Allowed imports

Forbidden forms

Literals

Flow control

Functions

Exceptions

Comprehensions

Attribute and property syntax

Expressions

Minimal snippet structure

Minimal parametric snippet structure

​Allowed imports

​Forbidden forms

​Literals

​Flow control

​Functions

​Exceptions

​Comprehensions

​Attribute and property syntax

​Expressions

​Minimal snippet structure

​Minimal parametric snippet structure

Allowed imports

Forbidden forms

Literals

Flow control

Functions

Exceptions

Comprehensions

Attribute and property syntax

Expressions

Minimal snippet structure

Minimal parametric snippet structure