> ## Documentation Index
> Fetch the complete documentation index at: https://aether.baimoqilin.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Service Registry: Invoke and Inspect Aether Services

> Use the services API to list, describe, and invoke Aether's built-in services — including skills and state — and replace them from a Native Mod.

Aether exposes a discoverable service registry that your extension can query and call at runtime. You can invoke built-in services such as `skills` directly from any extension, and — when writing a Native Mod — register higher-priority implementations that replace the defaults entirely.

## API reference

```typescript theme={null}
readonly services: {
  list(): Promise<object>;
  describe(service: string): Promise<object>;
  invoke(service: string, method: string, args?: object): Promise<object>;
};
```

## Listing available services

Call `services.list()` to retrieve the full catalog of registered services:

```typescript theme={null}
const catalog = await aether.services.list();
```

## Describing a service

Call `services.describe()` with a service ID to inspect its available methods and metadata:

```typescript theme={null}
const skillsApi = await aether.services.describe("skills");
```

## Built-in services

### `skills` service

The `skills` service exposes Aether's native Skill selection state.

| Method         | Arguments                                    | Description                          |
| -------------- | -------------------------------------------- | ------------------------------------ |
| `list`         | —                                            | Returns all installed Skills         |
| `getSelection` | —                                            | Returns currently selected Skill IDs |
| `setSelection` | `{ ids, scope, session_id? }`                | Set the full selection               |
| `setSelected`  | `{ skill_id, selected, scope, session_id? }` | Toggle a single Skill                |

**Scope values:** `"current"`, `"default"` / `"global"`, `"both"` / `"current_and_default"`. Using `"both"` updates the current session selection and the default selection independently.

```typescript theme={null}
// List all skills
const skills = await aether.services.invoke("skills", "list");

// Get currently selected skills
const selection = await aether.services.invoke("skills", "getSelection");

// Enable a skill for the current chat
await aether.services.invoke("skills", "setSelected", {
  skill_id: "web-search",
  selected: true,
  scope: "current",
});

// Set default skills for all new chats
await aether.services.invoke("skills", "setSelection", {
  ids: ["web-search", "code-interpreter"],
  scope: "default",
});
```

### `state` service

The `state` service provides direct read and transactional write access to Aether's application state.

| Method        | Arguments        | Description           |
| ------------- | ---------------- | --------------------- |
| `get`         | `{ path }`       | Read state at path    |
| `transaction` | `{ operations }` | Apply state mutations |

## Priority system

Services are priority-ordered. The active implementation for a given service ID is always the highest-priority registration. When you remove a registration, the next-highest-priority implementation becomes active. Aether's core services intentionally use a low priority, so a Native Mod registering the same service ID at the default Native Mod priority will seamlessly override the built-in behavior.

<Note>
  Script Mods can call any registered service using `aether.services.invoke()`, but they cannot register new service implementations. To override a built-in service or add a new one, you must use a Native Mod.
</Note>