FreeCAD MCP bridge (blwfish/freecad-mcp)MCADConfidence: Medium

A FreeCAD MCP bridge silently ignored parameters the client materialized from JSON-Schema defaults, so box(size=20) produced a default 10mm shape. The agent believes it built the requested geometry while the model is something else entirely.

Impact Analysis

Persona

Mechanical Designer

Team Size Impact

5x Multiplier

Prototype Delay

1 Days

Est. Annual Cost

$13,500

1 user · 1 month180 min
Rest of team720 min
Rest of year9,900 min

monthly_minutes × 12 × team_multiplier ÷ 60 × $75/hr = $13.5k/yr

$75/hr assumed rate.

Annual team-minutes decomposed from the reported monthly inputs.

Evidence & Sources

1 Sources

freecad-mcp issue #98: primitive tools rejected on materialized defaults; underlying silent-default geometry hazard

github.com

→

Analyst Notes

From the 2026-10-05 pain-radar digest (finding 1): external user report, maintainer fixed in v8.2.3 the same day and the user verified live. The maintainer's own quote names the hazard: ignored params silently produce default 10mm shapes. Cost model assumes manual dimension verification after every agent-built primitive.