# POST /ui/wait

Wait for a selector to appear or disappear.

This is a device HTTP route. Set `DEVICE_URL` to your reachable device URL; [connection and examples](https://mcp.applesauceos.com/doc/http.md) explain how. Do not append this path to the public MCP URL.

## Parameters

| Parameter | Type | Meaning |
| --- | --- | --- |
| `bundleId` | JSON string | Optional foreground app identifier. |
| `selector` | JSON object | Required UIHelper selector. |
| `condition` | JSON string | exists (default) or absent. |
| `timeoutMs` | JSON number | 0..10000 milliseconds; default 5000. |
| `intervalMs` | JSON number | 100..2000 milliseconds; default 200. |

## Response

On success: {matched:true,condition,count,elapsedMs}. Timeout: HTTP 408 with error,message,condition,lastQuery.

## Example

```sh
curl --fail-with-body "$DEVICE_URL/ui/wait" \
  -H 'Content-Type: application/json' \
  -d '{"selector":{"id":"loading","visible":true},"condition":"absent","timeoutMs":5000}'
```

## Notes

Unlike JavaScript waitForElement, this returns condition evidence, not an Element object or observation reference. It checks immediately; an individual helper request can outlast the polling deadline.

Check the HTTP status and any JSON error. [HTTP workflows and error handling](https://mcp.applesauceos.com/doc/http-guide.md) explain shared limits. [All endpoints](https://mcp.applesauceos.com/doc/http.md).