What causes "no supported standalone light found" in AprilNEA/OpenLogi?

Plug in the Logitech light and confirm the OS sees it (check System Information / lsusb).

no supported standalone light found

Error message

no supported standalone light found

What it means

The CLI's light `select` helper enumerates standalone (non-receiver) lights and picks one automatically only when exactly one is connected. When the enumeration result is empty and no `--device` query was supplied, there is nothing to auto-select, so it throws "no supported standalone light found". It is an upfront precondition failure, not an I/O failure: the command never reached a device.

Solutions

Plug in the Logitech light and confirm the OS sees it (check System Information / lsusb).
Run `openlogi list` to verify the light is enumerated as a standalone device.
On macOS, grant Input Monitoring to the OpenLogi agent process, then restart it.
If the light is a non-Litra product, confirm it is in the supported-model table; unsupported products are not enumerated as supported standalone lights.

Example fix

// before (CLI invocation relying on auto-select with no device attached)
$ openlogi light set-power on
error: no supported standalone light found

// after
$ openlogi light set-power on --device "Litra Glow"  # or plug the light in first

Defensive patterns

Strategy: validation

Validate before calling

let devices = openlogi_cli::cmd::light::standalone_devices()?; // or your enumeration source
if devices.is_empty() {
    eprintln!("no supported standalone light attached; connect a Litra and retry");
    return Ok(());
}

Prevention

Always enumerate and check the standalone-light list before invoking a light command.
On macOS verify Input Monitoring is granted before first use.
Distinguish receiver-connected devices from standalone ones when scripting.

When it happens

Trigger: Calling any of the light commands (`set_power`, `set_brightness`, `set_temperature`, or `selection_requires_disambiguation_and_supports_name_queries`) without `--device` while the enumerated `StandaloneDevice` list is empty (a `[]` slice passed to `select`).

Common situations: No Logitech Litra (Glow/Litra Beam etc.) is plugged in; the light is connected via a receiver and thus not listed as standalone; the HID backend lacks permission to see the device (e.g. macOS Input Monitoring not granted) so enumeration returns nothing; or a typo in an unsupported product means it was filtered out as 'supported'.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

AI-assisted analysis of AprilNEA/OpenLogi@e846e6f4b4 (2026-09-13). Data as JSON: /api/errors/d061a5ca33b873af. Report an issue: GitHub.

Appendix: source

Thrown at crates/openlogi-cli/src/cmd/light.rs:184

    let route = DeviceRoute::RawHid {
        vendor_id: device.address.vendor_id,
        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}"));
    };

View on GitHub (pinned to e846e6f4b4)