Unity Prefab Skills

BATCH-FIRST: Use prefab_instantiate_batch when spawning 2+ prefab instances.

Guardrails

Mode: Full-Auto required

DO NOT (common hallucinations):

• prefab_create_from_object does not exist → use prefab_create (takes scene object name/instanceId and savePath)
• prefab_spawn does not exist → use prefab_instantiate
• prefab_edit / prefab_modify do not exist → use prefab_set_property (edit prefab asset directly) or instantiate, modify, then prefab_apply
• prefab_save does not exist → use prefab_apply (applies instance changes to source prefab)

Routing:

• To modify components on a prefab instance in scene → use component module skills, then prefab_apply
• To set a property directly on the prefab asset → prefab_set_property (this module)
• To find all instances of a prefab → prefab_find_instances (this module)

Skills Overview

| Single Object | Batch Version | Use Batch When | |---------------|---------------|----------------| | prefab_instantiate | prefab_instantiate_batch | Spawning 2+ instances |

No batch needed:

• prefab_create - Create prefab from scene object
• prefab_apply - Apply instance changes to prefab
• prefab_unpack - Unpack prefab instance
• prefab_get_overrides - Get instance overrides
• prefab_revert_overrides - Revert to prefab values
• prefab_apply_overrides - Apply overrides to prefab
• prefab_create_variant - Create a prefab variant
• prefab_find_instances - Find all instances of a prefab in scene
• prefab_set_property - Set a property on a component inside a Prefab asset (supports basic types, vectors, colors, and asset references)

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Skills

prefab_create

Create a prefab from a scene GameObject.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | name | string | No* | Source object name | | instanceId | int | No* | Instance ID | | path | string | No* | Object path | | instanceId | int | No* | Instance ID | | savePath | string | Yes | Prefab save path |

Returns: {success, prefabPath, sourceObject}

prefab_instantiate

Instantiate a prefab into the scene.

| Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | prefabPath | string | Yes | - | Prefab asset path | | name | string | No | prefab name | Instance name | | x, y, z | float | No | 0 | Local position (relative to parent if set) | | parentName | string | No | null | Parent object name | | parentInstanceId | int | No | 0 | Parent instance ID | | parentPath | string | No | null | Parent hierarchy path |

Returns: {success, name, instanceId, path, prefabPath, position}

prefab_instantiate_batch

Instantiate multiple prefabs in one call.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | items | array | Yes | Array of instantiation configs |

Item properties: prefabPath, name, x, y, z, rotX, rotY, rotZ, scaleX, scaleY, scaleZ, parentName, parentInstanceId, parentPath

Returns: {success, totalItems, successCount, failCount, results: [{success, name, instanceId, prefabPath, position}]}

unity_skills.call_skill("prefab_instantiate_batch", items=[
    {"prefabPath": "Assets/Prefabs/Enemy.prefab", "x": 0, "z": 0, "name": "Enemy_01"},
    {"prefabPath": "Assets/Prefabs/Enemy.prefab", "x": 2, "z": 0, "name": "Enemy_02"},
    {"prefabPath": "Assets/Prefabs/Enemy.prefab", "x": 4, "z": 0, "name": "Enemy_03"}
])

prefab_apply

Apply instance changes back to the prefab asset.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | name | string | No* | Prefab instance name | | instanceId | int | No* | Instance ID | | path | string | No* | Object path | | instanceId | int | No* | Instance ID |

Returns: {success, gameObject, prefabPath}

prefab_unpack

Unpack a prefab instance (break prefab connection).

| Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | name | string | No* | - | Prefab instance name | | instanceId | int | No* | - | Instance ID | | path | string | No* | - | Object path | | instanceId | int | No* | - | Instance ID | | completely | bool | No | false | Unpack all nested prefabs |

Returns: {success, gameObject, mode}

prefab_get_overrides

Get list of property overrides on a prefab instance.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | name | string | No* | Prefab instance name | | instanceId | int | No* | Instance ID |

Returns: {success, overrides: [{type, path, property}]}

prefab_revert_overrides

Revert all overrides on a prefab instance back to prefab values.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | name | string | No* | Prefab instance name | | instanceId | int | No* | Instance ID |

prefab_apply_overrides

Apply all overrides from instance to source prefab asset.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | name | string | No* | Prefab instance name | | instanceId | int | No* | Instance ID |

prefab_create_variant

Create a prefab variant from an existing prefab.

| Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | sourcePrefabPath | string | Yes | - | Path to the source prefab asset | | variantPath | string | Yes | - | Save path for the new variant |

Returns: { success, sourcePath, variantPath, name }

prefab_find_instances

Find all instances of a prefab in the current scene.

| Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | prefabPath | string | Yes | - | Prefab asset path to search for | | limit | int | No | 50 | Maximum number of instances to return |

Returns: { success, prefabPath, count, instances: [{ name, path, instanceId }] }

prefab_set_property

Set a property on a component inside a Prefab asset file (without instantiating it). Supports basic types, vectors, colors, enums, and asset references.

| Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | prefabPath | string | Yes | - | Path to the prefab asset | | componentType | string | Yes | - | Component type name | | propertyName | string | Yes | - | Serialized property name | | value | string | Cond. | null | Value for basic types (int/float/bool/string/enum/vector/color) | | assetReferencePath | string | Cond. | null | Asset path for Object reference fields (Material, Texture, AudioClip, ScriptableObject, etc.) | | gameObjectName | string | No | null | Child object name inside prefab (defaults to root) |

Provide either value (basic types) or assetReferencePath (asset references).

Returns: { success, prefabPath, gameObject, component, property, valueSet }

# Set a float property on prefab root
unity_skills.call_skill("prefab_set_property",
    prefabPath="Assets/Prefabs/Enemy.prefab",
    componentType="EnemyStats",
    propertyName="maxHealth",
    value="100"
)

# Assign an asset reference to a prefab component
unity_skills.call_skill("prefab_set_property",
    prefabPath="Assets/Prefabs/Enemy.prefab",
    componentType="AudioSource",
    propertyName="m_audioClip",
    assetReferencePath="Assets/Audio/hit.wav"
)

# Edit a child object inside a prefab
unity_skills.call_skill("prefab_set_property",
    prefabPath="Assets/Prefabs/Player.prefab",
    componentType="MeshRenderer",
    propertyName="m_Materials.Array.data[0]",
    assetReferencePath="Assets/Materials/PlayerSkin.mat",
    gameObjectName="Body"
)

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Example: Efficient Enemy Spawning

import unity_skills

# BAD: 10 API calls for 10 enemies
for i in range(10):
    unity_skills.call_skill("prefab_instantiate",
        prefabPath="Assets/Prefabs/Enemy.prefab",
        name=f"Enemy_{i}",
        x=i * 2
    )

# GOOD: 1 API call for 10 enemies
unity_skills.call_skill("prefab_instantiate_batch", items=[
    {"prefabPath": "Assets/Prefabs/Enemy.prefab", "name": f"Enemy_{i}", "x": i * 2}
    for i in range(10)
])

Best Practices

1. Organize prefabs in dedicated folders
2. Use prefabs for repeated objects
3. Apply changes to update all instances
4. Unpack only when unique modifications needed
5. Use batch instantiation for level generation

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Exact Signatures

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