Reusable Skills, Templates, and Session Context¶

Unity Biome MCP can store small project-local automations under .claude/:

• a learned skill is saved C# or batch text plus a description;
• a template is a saved C# snippet for recreating scene content;
• session context is a compact hierarchy summary for comparison after a reconnect or restart.

These helpers are different from the agent instruction skills installed by the Unity setup wizard. Treat learned skills and templates as executable project code: review them before reuse and keep only trusted content.

Save and run a learned skill¶

Batch skill¶

Batch text is a good fit for a short sequence of existing MCP commands:

await save_skill(
    name="create_marker",
    description="Create a positioned cube under /Markers",
    code=(
        "create_object name=${name} primitive=Cube parent=/Markers\n"
        "set_property path=/Markers/${name} component=Transform "
        "prop=m_LocalPosition value=${position}"
    ),
)

result = await use_skill(
    "create_marker",
    params="name=SpawnA,position=(1,0,2)",
)

C# skill¶

Code containing common C# tokens is stored as a C# skill and later runs through execute_code:

await save_skill(
    name="reset_player_position",
    description="Move /Player to the origin",
    code='''
var player = GameObject.Find("Player");
if (player == null) throw new System.Exception("Player not found");
UnityEditor.Undo.RecordObject(player.transform, "Reset Player Position");
player.transform.position = Vector3.zero;
return player.transform.position.ToString();
''',
)

result = await use_skill("reset_player_position")

Placeholders use ${key}. Pass replacements as comma-separated key=value pairs. Commas inside parentheses are kept together, so Vector values such as (1,0,2) work. Substitution is textual and does not validate C# or escape values; do not pass untrusted text into executable templates.

Use list_skills() to see each saved skill's kind, description, and use count. Names cannot contain /, \\, or ...

Save and apply a scene template¶

A template is always C# and is stored as a .cs snippet:

await save_template(
    name="marker_row",
    code='''
var root = new GameObject("${name}");
for (int i = 0; i < ${count}; i++)
{
    var marker = GameObject.CreatePrimitive(PrimitiveType.Cube);
    marker.name = $"Marker_{i}";
    marker.transform.SetParent(root.transform);
    marker.transform.localPosition = new Vector3(i * ${spacing}, 0, 0);
}
return root.name;
''',
)

result = await apply_template(
    "marker_row",
    params="name=SpawnMarkers,count=4,spacing=2.5",
)

list_templates() returns the available template names. apply_template executes the substituted snippet with an Undo label, but only operations that explicitly use Unity Undo APIs are guaranteed to participate in Undo. Verify the hierarchy after applying a template.

Save session context¶

saved = await save_session()
# ...reconnect or restart the MCP client...
comparison = await load_session()

save_session stores a timestamp and compact hierarchy summary. load_session prints that previous summary beside a fresh current summary. It does not reopen scenes, restore object values, or roll back changes. Use it as cold-start orientation, then inspect the relevant subtree before editing.

For restorable file/scene checkpoints and recovery constraints, use System Tools.

Track and compare changes¶

Cross-cutting state helpers have canonical documentation elsewhere:

• get_changes returns editor events since the previous read; clear=False keeps them for the next call.
• fingerprint provides a cheap hash for “did this subtree change?” checks.
• scene_diff compares serialized hierarchy lines with its previous snapshot.
• screenshot_baseline and screenshot_compare provide visual regression evidence.

These mechanisms answer different questions; none is a replacement for a saved Unity scene or source control.

Storage¶

Decide explicitly whether these local automation files belong in version control. They can contain project paths and executable code, and the .claude directory is commonly ignored.