# @leumas/capability-sdk

The register-capability SDK — any page/plugin registers live functioncalls the Leviathan widget picks up on mount (and drops on unmount), plus the client-side trigger runtime (wakeword/hotkey/dom)...


**Register capabilities from any component — Leviathan picks them up live.** The frontend half of
the programmability layer (ported from leumas-cursor-agent-mvp's Leviathan, see provenance files):
scope-map capability registry, client trigger runtime (wakeword/wakephrase/hotkey/dom/route/idle),
client action registry (matching `@leumas/actions` manifests), the safe flows engine, self-authored
runtime capabilities, and the realtime-voice WebRTC hook.

```jsx
import { CapabilityProvider, TriggerRuntime, useRegisterCapability, createClientActionRegistry } from '@leumas/capability-sdk';
import { LeviathanWidget } from '@leumas/leviathan';

// App root (Studio/Web): provider → trigger runtime → widget
<CapabilityProvider>
  <TriggerRuntime actionRegistry={createClientActionRegistry({ navigate })}>
    <App />
    <LeviathanWidget client={leviathanClient} />
  </TriggerRuntime>
</CapabilityProvider>

// Any page: capabilities register on mount, unregister on unmount
useRegisterCapability([
  { name: 'add_contact', description: 'Add a contact', parameters: {...}, call: (args) => addContact(args) },
], { scopeId: 'contacts', pageTitle: 'Contacts' });
```

Everything meets on the shared `bus` (`capabilities:changed`, `leviathan:open`, `trigger:fired`,
`action:run`, `wakeword:simulate` — `simulateHear('leviathan')` is the mic-free test hook). Rules
with `runtime:'client'` arm in the browser; server rules reach the page as SSE directives.


---
Source: shared/packages/capability-sdk/README.md
Canonical: https://docs.leumas.tech/p/packages/capability-sdk