> ## Documentation Index
> Fetch the complete documentation index at: https://developer.eka.care/llms.txt
> Use this file to discover all available pages before exploring further.

# Quickstart

> Build a custom MedAssist UI on the raw Synapse core SDK

`@eka-care/medassist-core` is the foundation the embed and React widgets are built on. It manages the session, real-time connection, message transport, tool calls, and audio — and leaves the entire UI to you. Reach for it when you want a fully bespoke chat experience.

<Info>
  If you want a ready-made UI, use the [React SDK](/ai-tools/synapse/react/installation) or [embed widget](/ai-tools/synapse/embed/quickstart) instead. The core SDK is for building your own.
</Info>

## Install

```bash theme={null}
npm install @eka-care/medassist-core
```

## The lifecycle

<Steps>
  <Step title="Instantiate">
    Create a `SynapseSDK` with your `agentId` and options.
  </Step>

  <Step title="Start a session">
    `startSession()` connects and returns the session info (including any initial message).
  </Step>

  <Step title="Listen for events">
    Subscribe with `on()` to receive streamed message chunks, tool calls, and errors.
  </Step>

  <Step title="Send messages">
    Call `sendMessage()` to send text, files, audio, or tool results.
  </Step>

  <Step title="End the session">
    `endSession()` closes the connection and cleans up.
  </Step>
</Steps>

## End-to-end example

```ts theme={null}
import { SynapseSDK, SYNAPSE_REALTIME_EVENTS } from "@eka-care/medassist-core";

// 1. Instantiate
const sdk = new SynapseSDK({
  agentId: "YOUR_AGENT_ID",
  environment: "production",
  context: {
    profile: { name: "John Doe", age: 30, gender: "M" },
  },
  callbacks: {
    onError: (error) => console.error("SDK error:", error),
    onSessionRefreshed: (session) => console.log("refreshed:", session.session_id),
  },
});

// 2. Start the session
const session = await sdk.startSession();
console.log("connected:", session.session_id);

// 3. Listen for events
sdk.on(SYNAPSE_REALTIME_EVENTS.MESSAGE_CHUNK, (evt) => {
  process.stdout.write(evt.data.text ?? "");
});
sdk.on(SYNAPSE_REALTIME_EVENTS.END_OF_STREAM, () => console.log("\n--- done ---"));
sdk.on(SYNAPSE_REALTIME_EVENTS.ERROR, (err) => console.error("stream error:", err));

// 4. Send a message
await sdk.sendMessage({ message: "I have chest pain" });

// 5. End when finished
// sdk.endSession();
```

## Constructor options

`new SynapseSDK(config)` accepts:

<ParamField path="agentId" type="string" required>
  Your MedAssist agent identifier.
</ParamField>

<ParamField path="environment" type="&#x22;development&#x22; | &#x22;staging&#x22; | &#x22;production&#x22;" default="production">
  Which backend to connect to.
</ParamField>

<ParamField path="userId" type="string">
  Optional user identifier.
</ParamField>

<ParamField path="connectionType" type="ConnectionType" default="ConnectionType.SSE">
  `ConnectionType.SSE` or `ConnectionType.SOCKET`.
</ParamField>

<ParamField path="context" type="TContext">
  User context — `profile`, `intent`, `user_location`, `referer`, and any custom keys. See the [API reference](/ai-tools/synapse/core/api-reference#tcontext).
</ParamField>

<ParamField path="overrides" type="SynapseSDKOverrides">
  UI/behavior overrides — `prompt`, `firstMessage`, `language`, `primaryColor`.
</ParamField>

<ParamField path="callbacks" type="SynapseSDKCallbacks">
  `onSessionRefreshed` and `onError` callbacks.
</ParamField>

<ParamField path="auth" type="string">
  Optional auth header.
</ParamField>

<ParamField path="authToken" type="string">
  Optional auth token.
</ParamField>

<ParamField path="serverUrl" type="string">
  Optional custom server URL.
</ParamField>

## Next steps

<CardGroup cols={2}>
  <Card title="Events" icon="bolt" href="/ai-tools/synapse/core/events">
    Subscribe to streamed messages, tips, and lifecycle events.
  </Card>

  <Card title="Tool calls & elicitation" icon="hand-pointer" href="/ai-tools/synapse/core/tool-calls">
    Render the inputs the agent asks for and reply with results.
  </Card>

  <Card title="Voice & audio" icon="microphone" href="/ai-tools/synapse/core/voice">
    Record audio and run voice-mode conversations.
  </Card>

  <Card title="API reference" icon="book" href="/ai-tools/synapse/core/api-reference">
    Every method, type, and enum.
  </Card>
</CardGroup>