Component events¶

wire_event, list_events, and unwire_event manage persistent listeners on serialized UnityEvent fields. They do not turn ordinary Unity callbacks such as OnTriggerEnter into events.

Enable the COMPONENTS category before using these tools.

Inspect listeners first¶

Read the current listener list before changing it:

listeners = await list_events(
    path="/Canvas/StartButton",
    component="Button",
    event="onClick",
)

The response includes the zero-based listener index, target path and type, method, call state, and any static argument. An empty event reports zero listeners.

Use the serialized event-field name. Built-in components commonly use names such as onClick and onValueChanged; custom scripts may expose fields such as _onCompleted.

Add a persistent listener¶

For a no-argument method:

await wire_event(
    path="/Canvas/StartButton",
    component="Button",
    event="onClick",
    target="/GameManager",
    method="StartGame",
)

For a static argument, set both its type and value:

await wire_event(
    path="/Canvas/DifficultyButton",
    component="Button",
    event="onClick",
    target="/GameManager",
    method="SetDifficulty",
    arg_type="int",
    arg_value="2",
    target_component_type="GameManager",
    parameter_types="int",
)

Supported static argument types are void, bool, int, float, string, and object. An object argument resolves from a scene path or asset path.

When several target components expose the method, pass target_component_type. When the selected component has overloads, also pass comma-separated parameter_types, for example "string" or "int,float". The tool rejects an unresolved ambiguity instead of choosing silently.

The target can be a scene object or an asset. For scene objects, a component owning the method is selected; GameObject itself remains a fallback for methods such as SetActive.

Remove listeners¶

Remove one listener by the index returned from list_events:

await unwire_event(
    path="/Canvas/StartButton",
    component="Button",
    event="onClick",
    index=0,
)

Omit index to clear all persistent listeners from that one event:

await unwire_event(
    path="/Canvas/StartButton",
    component="Button",
    event="onClick",
)

Clearing is intentionally broad. Inspect first when existing listeners may belong to another system.

Verify the complete workflow¶

before = await list_events(
    path="/Canvas/StartButton", component="Button", event="onClick"
)

await wire_event(
    path="/Canvas/StartButton",
    component="Button",
    event="onClick",
    target="/GameManager",
    method="StartGame",
    target_component_type="GameManager",
)

after = await list_events(
    path="/Canvas/StartButton", component="Button", event="onClick"
)

Require after to contain the expected target type and method. Then enter Play Mode and exercise the control if runtime behavior matters:

await editor(action="play")
try:
    result = await run_playtest(
        script="CLICK /Canvas/StartButton WAIT 0.5\nASSERT_CONSOLE_CLEAN"
    )
finally:
    await editor(action="stop")

wire_event and unwire_event participate in Unity Undo for scene components. Save the scene only after readback and runtime verification succeed.

See UI Tools for creating controls and the generated schema for exact parameters.