Capability discovery

Archived SDK documentation

This page preserves the previous SDK documentation and its existing URL. The generated API reference was produced from SDK 0.1.5, source commit 4db9fbe925bf07a4b95e936a5bb172d6ab5820bb. Handbook behavior and compatibility claims below are historical descriptions, not a newly verified support guarantee. For the reviewed version-specific reference, see the SDK 0.1.5 overview.

Endpoints in Delphi are not all the same. One endpoint may be voice-only, another text-only, another a multimodal AI agent with bespoke browser-action flows. The SDK exposes a small API for querying that surface before opening a session.

getCapabilities

const capabilities = await delphi.getCapabilities(endpointId);

console.log(capabilities.interactionModes);
// → { text: true, audio_playback: true, voice_conversation: true, … }

console.log(capabilities.flows.entryPoints);
// → ['web_chat', 'web_voice', 'phone']

console.log(capabilities.runtime.migration);
// → ['text_to_voice', 'voice_to_text', 'api_to_media'] when both web entry points exist

hasCapability

Predicate form. Returns boolean.

if (!delphi.hasCapability(capabilities, 'voice_conversation')) {
  throw new Error('This endpoint does not support voice calls.');
}

assertCapability

Throws CapabilityNotSupportedError when the capability is missing.

delphi.assertCapability(capabilities, 'audio_playback');
// proceeds, or throws

assertEndpointCapability

Convenience: fetch capabilities and assert in one call.

const caps = await delphi.assertEndpointCapability(endpointId, 'audio_playback');

console.log(caps.flows.browserActions);

Session migration

capabilities.runtime.migration lists which live handoffs TelAPI supports for this endpoint:

Value	Meaning
text_to_voice	Active text session can upgrade to WebRTC voice on the same sessionId.
voice_to_text	Active voice_conversation can downgrade back to text.
api_to_media	Other API-initiated media transitions (platform-internal).

Both text_to_voice and voice_to_text appear only when the flow defines web_chat and web_voice entry points. Gate “Upgrade to voice” / “Switch to text chat” buttons on these flags — see Text chat quick start.

Browser-action discovery

capabilities.flows.browserActions enumerates the BOA flows the endpoint exposes. The fields:

Field	Meaning
id	Stable capability id, suitable for capabilityId on readAloud.
slug	URL-friendly identifier.
label	Human-readable name.
type	Capability type (e.g. read_aloud, transform_and_read, custom).
messageType	The exact browser.action.* message the server expects. Used by sendBrowserAction.
voiceInvocable	Whether the AI can trigger this BOA mid-call.

For readAloud the SDK picks the right BOA automatically; supply capabilityId or identifier only when an endpoint exposes multiple read-aloud BOAs and you need to disambiguate.

Error type

The thrown error from assertCapability / assertEndpointCapability:

import {CapabilityNotSupportedError} from '@ki-kombinat/delphi-client-js-sdk';

try {
  delphi.assertCapability(capabilities, 'voice_conversation');
} catch (err) {
  if (err instanceof CapabilityNotSupportedError) {
    console.warn(`Endpoint missing capability: ${err.capability}`);
  }
}

See Errors for the full list of typed errors the SDK exposes.

Next step

Jump into a text chat, read-aloud quick start, or a voice call.