Function value_invalid 

pub fn value_invalid(
    ctx: Context,
    node_type: &str,
    op: &str,
    store: &str,
    msg: String,
) -> PluginExecutionError

A value that exists but is not usable as configured (bad JSON, non-numeric). Prepares a 500: a data/config fault, not an outage.

Only ever raised on the redis-backed data path – see key_invalid.