multiple standalone lights found; select one with --device

Error message

multiple standalone lights found; select one with --device

What it means

When no `--device` query is given and more than one supported standalone light is connected, `select` refuses to guess which one the command targets and fails with this message. The error exists to force explicit disambiguation rather than silently applying a command to an arbitrary device.

Solutions

Re-run the command with `--device <name-or-serial-substring>` identifying the intended light.
Run `openlogi list` (or the light list command) to see the display names/identities available for `--device`.
Physically disconnect or power off the other lights if you prefer the auto-select convenience.

Example fix

// before — two lights attached, no selector
$ openlogi light set-brightness 40
error: multiple standalone lights found; select one with --device

// after
$ openlogi light set-brightness 40 --device "Beam"

Defensive patterns

Strategy: validation

Validate before calling

let devices = /* enumerate */;
if devices.len() > 1 && device_query.is_none() {
    eprintln!("{} lights attached; pass --device", devices.len());
    // print names to pick from
}

Prevention

Make --device a required parameter in scripts when more than one light may be attached.
List devices first and bake the chosen identity into automation configs.
Keep only one light attached on interactive machines if you rely on auto-select.

When it happens

Trigger: Calling `set_power`, `set_brightness`, or `set_temperature` (or `selection_requires_disambiguation_and_supports_name_queries`) without `--device` while `select` receives a `devices` slice with two or more `StandaloneDevice` entries.

Common situations: Two Litra Glows (or a Glow plus a Litra Beam) are attached; a dock with multiple lights is connected; you intended to target one light but forgot the `--device` flag after adding a second unit.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

AI-assisted analysis of AprilNEA/OpenLogi@e846e6f4b4 (2026-09-13). Data as JSON: /api/errors/dc6ba78b98f9a3ce. Report an issue: GitHub.

Appendix: source

Thrown at crates/openlogi-cli/src/cmd/light.rs:186

        product_id: device.address.product_id,
        usage_page: device.address.usage_page,
        usage_id: device.address.usage_id,
        identity: device.address.identity.clone(),
    };
    openlogi_hid::apply_litra(&route, model, command)
        .await
        .context("failed to write the light command")
}

fn select<'a>(
    devices: &'a [StandaloneDevice],
    query: Option<&str>,
) -> Result<&'a StandaloneDevice> {
    let Some(query) = query else {
        return match devices {
            [] => Err(anyhow!("no supported standalone light found")),
            [device] => Ok(device),
            _ => Err(anyhow!(
                "multiple standalone lights found; select one with --device"
            )),
        };
    };
    let query = query.to_ascii_lowercase();
    let mut matches = devices.iter().filter(|device| {
        device.display_name.to_ascii_lowercase().contains(&query)
            || device
                .address
                .identity
                .to_ascii_lowercase()
                .contains(&query)
    });
    let Some(device) = matches.next() else {
        return Err(anyhow!("no standalone light matches --device {query}"));
    };
    if matches.next().is_some() {
        return Err(anyhow!(

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