leathercad-ai

name	leathercad-ai
description	Use when generating, refining, validating, or repairing LeatherCad AI Builder JSON for leather templates, including pattern pieces, stitch paths, seam allowances, seam connections, hardware markers, stable @leather refs, and preflight issues.

LeatherCad AI Builder

Workflow

1. Treat AI Builder JSON as the source contract. Return only valid JSON, never markdown.
2. Prefer leather-native entities over raw geometry when intent is known:
   • stitch_path for stitch lines plus generated holes.
   • pattern_piece for closed cut boundaries.
   • seam_allowance for piece offsets.
   • seam_connection for edge mating intent.
   • hardware_marker for snaps, rivets, buckles, and custom fittings.
3. Use stable snake_case IDs. LeatherCad exposes compiled objects as @leather[kind:id] refs, so preserve existing IDs during refinements.
4. Generate in millimeters. Positive x moves right; positive y moves down.
5. Keep closed cut boundaries simple and inspectable. Rectangles are the safest boundary primitive; multi-entity boundaries should form a clean closed loop.
6. For refinements, output the full updated JSON document, not a diff.
7. Address preflight errors before adding decorative detail:
   • Closed pattern-piece boundaries.
   • Seam edge length mismatch.
   • Stitch paths with too few holes.
   • Fold radius versus material thickness.
   • Missing cut-line geometry for export.

Entity Patterns

Use a closed cut entity first, then bind it into a piece:

{
  "id": "outer_shell_piece",
  "type": "pattern_piece",
  "layer_id": "shell",
  "boundary_entity_id": "outer_shell_outline",
  "name": "Outer Shell",
  "quantity": 1
}

Use stitch_path instead of manually placing holes:

{
  "id": "bottom_stitching",
  "type": "stitch_path",
  "layer_id": "shell",
  "path_type": "line",
  "start": { "x": -90, "y": 38 },
  "end": { "x": 90, "y": 38 },
  "pitch_mm": 4,
  "hole_type": "slit",
  "render_shape": "diamond",
  "width_mm": 1.2,
  "height_mm": 0.55,
  "tilt_deg": 35
}

Use pattern-piece entity IDs for seams and allowances; LeatherCad maps them to native piece IDs during compile.