# Update device

> Update device.

`PATCH https://api.cymatics.tech/v1/devices/{device}`

Scope: `devices:write`

## Request

Send your key as `Authorization: Bearer cym_test_…`. Requires the `devices:write` scope. Test keys read the simulator; live keys read your paired Cymos.

| Name | In | Type | Required | Description |
| --- | --- | --- | --- | --- |
| `device` (SDK and CLI: `device_id`) | path | `string` | Yes | Device id |
| `Idempotency-Key` | header | `string` | No | Replays the first response for an identical request within the project and mode. |

## Request body

| Name | In | Type | Required | Description |
| --- | --- | --- | --- | --- |
| `room_id` | body | `string` | No |  |
| `light` | body | `on_interaction \| on \| off` | No |  |

```json
{
  "room_id": "room_bedroom",
  "light": "on_interaction"
}
```

## Response

`200 · application/json`

```json
{
  "data": {
    "object": "device",
    "id": "dev_bedroom",
    "room_id": "room_bedroom",
    "connection_status": "online",
    "pairing_state": "paired",
    "last_seen_at": "2026-10-24T23:55:30.000Z",
    "firmware_version": "firmware_version",
    "uptime": {
      "ratio_24h": 0,
      "ratio_30d": 0,
      "since": "2026-10-24T23:55:30.000Z"
    },
    "health": {
      "status": "healthy",
      "reasons": [
        "reason"
      ]
    },
    "simulated": true
  },
  "meta": {
    "request_id": "req_01",
    "project_id": "proj_demo",
    "livemode": false,
    "generated_at": "2026-10-24T23:55:30.000Z"
  }
}
```

## Errors

| Status | Description |
| --- | --- |
| `429` | `rate_limit_exceeded`: Too many requests this minute for the key (or twice that across the project), or too many open streams for the project. Retry after the seconds in Retry-After.<br>`quota_exceeded`: A live key's project has used its monthly live-hour cap. There is no Retry-After. Don't retry; raise the live-hour cap in the dashboard. Headers: Retry-After, RateLimit-Limit, RateLimit-Remaining, RateLimit-Reset. |
| `503` | `live_unavailable`: This operation has no live data for this project yet (for example, no paired Cymo covers it). Don't retry the same request; pair a Cymo that covers it, or build against a test key.<br>`service_unavailable`: A dependency, such as API key verification, is unreachable, or the project is busy with another write. Retry after the seconds in Retry-After, with backoff. |
| `4XX` | Invalid request, credential, permission or revision. |
| `default` | Error with a stable code and request ID. |

Every error is a `{ error, meta }` envelope with a stable `code`. See [Errors](https://docs.cymatics.tech/errors) for each code and whether to retry.

## Call it

**TypeScript · @cymos/sdk**

```ts
import { Cymo } from "@cymos/sdk";

const cymo = new Cymo({ apiKey: process.env.CYMO_API_KEY! });

const { data, meta } = await cymo.devices.update({
  device_id: "dev_bedroom",
  room_id: "room_bedroom",
  light: "on_interaction"
});
```

**terminal · cymatics CLI**

```sh
$ cymatics devices update --device-id dev_bedroom --input body.json --json
```

**curl**

```sh
curl -X PATCH "https://api.cymatics.tech/v1/devices/dev_bedroom" \
  -H "Authorization: Bearer $CYMO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"room_id":"room_bedroom","light":"on_interaction"}'
```

The SDK takes path parameters and body fields in one object. The CLI reads the body from `--input`, a JSON file or `-` for stdin.

**MCP tool**

```
update_device({
  device_id: "dev_bedroom",
  input: {
    room_id: "room_bedroom",
    light: "on_interaction"
  }
})
```

The MCP tool `update_device` calls this operation with your key. It takes the request body as `input`.