---

name: unity-prefab description: Manage Prefabs and variants

Before calling any skill in this module: if you are about to call a skill with parameters guessed from its name or description, STOP — read this file (or fetch its schema via GET /skills/recommend?includeSchema=true) first. If you already have the parameter definitions from recommend/schema, you may proceed straight to dryRun.

Triggers

• Creating or editing prefabs
• Instantiating or applying prefab changes
• Finding instances in scenes
• Creating prefab variants
• 创建或编辑预制体、实例化或应用预制体改动、在场景中查找实例、创建预制体变体

Unity Prefab Skills

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

Operating Mode

Approval 模式下本模块为 Mixed —— 只读 skill prefab_get_overrides / prefab_find_instances（标 ReadOnly = true, Mode = SkillMode.SemiAuto）可直接执行；其余 9 个写类 skill (prefab_create / prefab_instantiate / prefab_instantiate_batch / prefab_apply / prefab_unpack / prefab_revert_overrides / prefab_apply_overrides / prefab_create_variant / prefab_set_property) 为 SkillMode.FullAuto，需用户 grant 单次执行返结果。Auto / Bypass 直接执行。本模块不含 NeverInSemi 高危 skill（无 Delete / PlayMode / Reload）。

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)

---

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 (preferred) | | path | string | No* | Object path | | savePath | string | Yes | Prefab save path |

*At least one source identifier required.

Returns: {success, prefabPath, name}

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) | | parentEntityId | string | No | null | Parent entity ID (Unity 6000.4+, preferred) | | parentName | string | No | null | Parent object name | | parentInstanceId | int | No | 0 | Parent instance ID | | parentPath | string | No | null | Parent hierarchy path |

Returns: {success, name, entityId, instanceId, path}

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, parentEntityId, parentName, parentInstanceId, parentPath

Returns: {success, totalItems, successCount, failCount, results: [{success, name, entityId, instanceId, 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 (preferred) | | path | string | No* | Object path |

*At least one identifier required.

Returns: {success, appliedTo} (appliedTo is the prefab asset path)

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 (preferred) | | path | string | No* | - | Object path | | completely | bool | No | false | Unpack all nested prefabs |

*At least one identifier required.

Returns: {success, unpacked} (unpacked is the instance's GameObject name)

prefab_get_overrides

Get a summary of property overrides on a prefab instance (counts, not the individual override list).

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

Returns: {success, prefabPath, propertyOverrides, addedComponents, removedComponents, addedGameObjects, hasOverrides} — propertyOverrides/addedComponents/removedComponents/addedGameObjects are counts (int), not arrays; hasOverrides is true when any of those counts is non-zero.

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 |

Returns: {success, reverted} (reverted is the prefab root's GameObject name)

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 |

Returns: {success, appliedTo} (appliedTo is the prefab asset path)

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, entityId, 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/quaternion) | | 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).

value covers Integer, Float, Boolean, String, Enum, Color, Vector2/3/4, Vector2Int/3Int, Quaternion, Rect, Bounds and LayerMask. A quaternion (localRotation) accepts 3 components as euler degrees ("0,90,0") or 4 as raw x,y,z,w. Any other serialized type answers SEMANTIC_INVALID naming the type — that is the signal to use assetReferencePath, not to reformat value.

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"
)

---

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

---

Exact Signatures

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

Common Errors

Full transport-level codes (COMPILING/RATE_LIMIT etc.) → ../../references/protocol-error-codes.md

| Error | Trigger | Fix | |---|---|---| | TARGET_NOT_FOUND | The prefab asset, source prefab, child GameObject inside a prefab, component, or asset reference could not be found. | Confirm the prefab path with asset_find / prefab_find_instances, check child/component names, and retry with exact identifiers. | | MISSING_PARAM | A required parameter is missing, such as savePath, prefabPath, sourcePrefabPath, componentType, or propertyName. | Provide the missing parameter; use mode=dryRun to inspect the full schema. | | SEMANTIC_INVALID | The target is not a prefab instance, the property is not an Object reference field, or a serialized value could not be parsed. | Ensure the object is a prefab instance (prefab_get_overrides can verify), match the property type, and retry with a valid value. | | SKILL_ERROR | A low-level operation failed, such as Failed to instantiate prefab or Failed to set value ... (type: ...). | Resolve the underlying cause named in the message (e.g., prefab corruption, type mismatch) and retry. |