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

# Using a service

> Generate a typed client and call services from your app's backend

Apps consume services through auto-generated clients. Each tool defined in the service becomes a typed method on the client, and the framework handles credential resolution transparently.

## Generate a service client

```bash theme={null}
synthetiq service client <service-name>
```

This generates a typed client package (`@synthetiq/services-<name>-client`) that you can import in your app's backend code.

## Call a service from a backend procedure

```typescript theme={null}
// src/server/routes/channels.ts
import SlackClient from '@synthetiq/services-slack-client';
import { router, scopedProcedure } from '@synthetiq/app-framework/server';

export const channelsRouter = router({
  listChannels: scopedProcedure([])
    .meta({ description: 'List Slack channels' })
    .query(async () => {
      const client = new SlackClient();
      return await client.listChannels({ limit: 100 });
    }),
});
```

The client resolves the authenticated user's credentials at call time — no API keys or tokens appear in app code. Service clients can only be used in backend code (`src/server/`).

## Streaming calls

For services that support streaming (e.g., LLM providers), use the callback variant:

```typescript theme={null}
const client = new AnthropicClient();

let response = '';
await client.streamMessageWithCallback(
  {
    model: 'claude-sonnet-4-20250514',
    messages: [{ role: 'user', content: 'Hello' }],
    max_tokens: 1024,
  },
  (chunk) => { response += chunk; },
  () => { console.log('Complete:', response); },
  (error) => { console.error('Error:', error); },
);
```