UncheckedLiveQueryHandlerMissingError

What this error means and what can trigger it

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UncheckedLiveQueryHandlerMissingError means Query.live("unchecked", handler) reached its server factory without a truthy second argument. The sentinel removes input decoding, although the handler must still create the live Stream from Effect.

Once static typing has been bypassed, the guard catches omitted and other falsy values. A truthy value gets past this exact branch, albeit only for a non-callable value to fail later.

Exactly where it triggers

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if (is_unchecked(validate_or_handler)) {
	throw new UncheckedLiveQueryHandlerMissingError();
}

The surrounding try/catch, however, rethrows this existing error unchanged after helper normalization. It is raised synchronously while the remote export is created, before any live request starts.

For reference, the class is declared at modules/svelte-effect-runtime/src/errors.ts L421 @ C14.

Why this is the case

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Unchecked validation changes only the input boundary. A live query still needs code that selects a source, constructs a Stream, and defines its failure and environment requirements.

Treating the sentinel as a handler would create neither a callable operation nor a source that can be converted into SvelteKit's async iterable protocol.