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

# Multiple Radius instances

> Choose which running Radius instance receives a command.

Most users run one Radius instance, so no selection is required:

```bash theme={"theme":{"light":"github-light","dark":"github-dark"}}
radius app status
```

If multiple instances are running, Radius refuses to guess and returns
`INSTANCE_AMBIGUOUS`.

## Select an instance

Use an instance ID, release channel, or process ID:

```bash theme={"theme":{"light":"github-light","dark":"github-dark"}}
radius app status --instance <instance-id> --json
radius tab list --instance development --json
radius window list --instance 12345 --json
```

Radius terminals automatically target the instance that opened them, so
`--instance` is primarily useful from an external terminal.

## Start Radius on demand

On macOS:

```bash theme={"theme":{"light":"github-light","dark":"github-dark"}}
radius app status --launch --timeout-ms 15000
```

The command starts Radius when necessary and waits for it to become ready.

## Troubleshooting

List the available instances with the details returned by:

```bash theme={"theme":{"light":"github-light","dark":"github-dark"}}
radius doctor --json
```

Then rerun the command with an explicit `--instance` selector.