Unity Probuilder Agent Skill

Unity ProBuilder Skills

Use this module for editable ProBuilder meshes, not regular primitive GameObjects. It is best for blockout, level geometry, and procedural mesh refinement.

> Requires: com.unity.probuilder package.

> Batch-first: For scene blockout or level generation, prefer probuilder_create_batch when creating 2+ shapes.

Guardrails

Operating Mode (v1.9 three-tier):

• Approval (default): query skills (e.g. probuilder_get_info, probuilder_get_vertices) run directly. Create/modify skills are FullAuto — call once, get MODE_RESTRICTED, run the grant protocol; a successful /permission/grant executes the skill server-side and returns the result in the same response.
• Auto / Bypass: SemiAuto and FullAuto run directly.
• Auto-forbidden in this module: probuilder_combine_meshes (SkillOperation.Modify | Delete, the Delete bit triggers NeverInSemi). It is callable only under Bypass mode or after the user adds it to the Allowlist; the grant flow returns MODE_FORBIDDEN. Note probuilder_delete_faces is Operation = SkillOperation.Modify only and remains grantable under Approval/Auto.
• When com.unity.probuilder is missing, every skill returns a package-missing diagnostic instead of executing.

DO NOT (common hallucinations):

• probuilder_create_mesh does not exist -> use probuilder_create_shape
• probuilder_edit_face does not exist -> use the specific face skills such as probuilder_extrude_faces, probuilder_delete_faces, probuilder_merge_faces
• probuilder_set_material and probuilder_set_face_material are different -> whole object vs selected faces
• Regular meshes do not become ProBuilder meshes automatically
• Mesh rebuild calls (ToMesh() + Refresh()) are already handled by the skills. Do not invent a manual rebuild step

Routing:

• For ordinary primitive objects without editable topology -> use gameobject_create
• For material asset creation or shader work -> use material
• For large blockout generation -> combine this module with material and light, but keep geometry creation here

Object Targeting

Most edit/query skills accept one of:

• name
• instanceId
• path

Prefer instanceId when multiple scene objects share the same name.

Skills

Create and Batch

| Skill | Use | Key parameters |

|-------|-----|----------------|

| probuilder_create_shape | Create a parametric ProBuilder shape | shape, name?, x/y/z?, sizeX/Y/Z?, rotX/Y/Z? |

| probuilder_create_batch | Create multiple shapes in one call | items, defaultParent? |

Supported shape values: Cube, Sphere, Cylinder, Cone, Torus, Prism, Arch, Pipe, Stairs, Door, Plane.

Face and Edge Editing

| Skill | Use | Key parameters |

|-------|-----|----------------|

| probuilder_extrude_faces | Extrude selected faces | target, faceIndexes?, distance?, method? |

| probuilder_delete_faces | Delete faces by index | target, faceIndexes |

| probuilder_merge_faces | Merge faces into one | target, faceIndexes? |

| probuilder_flip_normals | Reverse face direction | target, faceIndexes? |

| probuilder_detach_faces | Split faces from shared vertices | target, faceIndexes?, deleteSourceFaces? |

| probuilder_bevel_edges | Chamfer edges | target, edgeIndexes?, amount? |

| probuilder_extrude_edges | Extrude edges outward | target, edgeIndexes, distance?, extrudeAsGroup? |

| probuilder_bridge_edges | Bridge two edges with new face | target, edgeA, edgeB, allowNonManifold? |

Mesh, Vertex, UV, Material

| Skill | Use | Key parameters |

|-------|-----|----------------|

| probuilder_subdivide | Add detail by subdivision | target, faceIndexes? |

| probuilder_conform_normals | Make normals point consistently outward | target, faceIndexes? |

| probuilder_move_vertices | Offset vertices by delta | target, vertexIndexes, deltaX/Y/Z? |

| probuilder_set_vertices | Set absolute vertex positions | target, vertices |

| probuilder_get_vertices | Query vertex positions | target, vertexIndexes?, verbose? |

| probuilder_weld_vertices | Merge close vertices | target, vertexIndexes, radius? |

| probuilder_project_uv | Box-project UVs | target, faceIndexes?, channel? |

| probuilder_set_face_material | Assign material to faces | target, faceIndexes?, materialPath?, submeshIndex? |

| probuilder_set_material | Assign whole-object material or quick color | target, materialPath?, r/g/b/a? |

| probuilder_combine_meshes | Merge multiple meshes | names |

Query and Pivot

| Skill | Use | Key parameters |

|-------|-----|----------------|

| probuilder_get_info | Get face/vertex/material stats | target |

| probuilder_center_pivot | Center or reposition pivot | target, worldX/Y/Z? |

Blockout Workflow

• Create major volumes with probuilder_create_batch.
• Verify traversal and gameplay scale before adding detail.
• Refine surfaces with face/edge operations.
• Use vertex edits for ramps, slopes, and irregular silhouettes.
• Apply quick colors or real materials after layout stabilizes.

Minimal Example

import unity_skills

unity_skills.call_skill("probuilder_create_batch", items=[
    {"shape": "Cube", "name": "Ground", "sizeX": 20, "sizeY": 0.5, "sizeZ": 12, "y": -0.25},
    {"shape": "Cube", "name": "Platform_A", "sizeX": 3, "sizeY": 0.3, "sizeZ": 3, "x": 4, "y": 1.5},
    {"shape": "Cube", "name": "Ramp", "sizeX": 3, "sizeY": 1, "sizeZ": 5, "x": 8, "y": 0.5}
])

unity_skills.call_skill("probuilder_move_vertices",
    name="Ramp",
    vertexIndexes="4,5",
    deltaY=-0.8
)

unity_skills.call_skill("probuilder_set_material",
    name="Platform_A",
    r=0.2, g=0.6, b=1.0
)

Important Notes

• ProBuilder objects keep editable topology through ProBuilderMesh.
• Use probuilder_get_info before face edits and probuilder_get_vertices before vertex edits.
• MeshCollider on physics-driven props must be convex.
• Quick color assignment is fine for prototype passes; use material assets for production.
• Package missing errors are expected if ProBuilder is not installed.

Exact Signatures

Exact names, parameters, defaults, and returns are defined by GET /skills/schema or unity_skills.get_skill_schema(), not by this file.

Load MODELING_REFERENCE.md for scene design heuristics, furniture decomposition, detailed examples, and extended modeling tips.