prefab-workflow

name	prefab-workflow
description	Use when creating or editing prefabs in the Unity Editor using MCP tools — saving prefabs, editing prefab contents, creating variants, and applying overrides.

Prefab Workflow with MCP Tools

Efficient tool sequences for prefab operations.

GOAL: Create a Prefab from Scene Objects

Approach:

1. Build the object in the scene first (easier to iterate).
2. Once satisfied, save as prefab asset.
3. The scene instance becomes a prefab instance automatically.

Tool sequence:

• Build in scene using scene_create_gameobject, component_add, etc.
• prefab_create — save scene object as prefab at target path.

Common mistakes:

• Creating parent directories manually — prefab_create handles this.
• Forgetting to save the scene after creating the prefab (scene now has a prefab instance).

GOAL: Edit a Prefab's Properties

Two approaches depending on scope:

Single property change (atomic):

• prefab_edit_property — load, edit one property, save. One tool call.

Multi-step changes (session):

• prefab_open_editing — opens prefab for editing, returns root path.
• Use component_add, component_set_property, reference_set, etc. on the opened prefab's hierarchy.
• prefab_save_editing — save and close.

Common mistakes:

• Using prefab_edit_property for many changes (inefficient — opens/saves per call).
• Forgetting prefab_save_editing (changes are lost).
• Trying to use scene tools on a prefab without opening it for editing first.

GOAL: Create a Prefab Variant

Approach:

1. Create variant from base prefab.
2. Edit the variant's overriding properties.

Tool sequence:

• prefab_create_variant — specify base prefab path and new variant path.
• prefab_edit_property — override specific values on the variant.

Common mistakes:

• Trying to remove components from a variant (not supported — can only add or override).
• Creating deeply nested variants (Base → Variant → Variant) — fragile, avoid.

GOAL: Instantiate Prefabs into the Scene

Approach:

1. Instantiate with optional parent.
2. Position/configure the instance.

Tool sequence:

• prefab_instantiate — create instance in scene, optionally parent it.
• component_set_property on Transform — set position, rotation, scale.
• reference_set — wire up any scene-specific references.

Common mistakes:

• Not parenting to an organizational empty (scene gets cluttered).
• Setting references to other prefab instances before they exist.

GOAL: Apply Overrides Back to Prefab

When to use: You edited a prefab instance in the scene and want those changes in the prefab asset.

Tool sequence:

• prefab_apply_overrides — applies all instance overrides back to the source prefab.

Common mistakes:

• Applying when unintended changes are present on the instance.
• Use inspector_inspect on the instance first to verify what will be applied.

GOAL: Inspect a Prefab Without Instantiating

Tool sequence:

• prefab_get_contents — returns the full hierarchy, components, and properties of a prefab asset without placing it in the scene.

Use for: Checking structure, verifying components, reading property values before deciding to instantiate or modify.

Related Skills

• uniclaude:prefab-architecture — when to use prefabs vs variants vs SOs
• uniclaude:unity-architect — system-level prefab strategy