Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
Somebody just tried to change what a thing is, and the engine said no. In rush, every being gets its Trinity kind at birth, noun, verb, or flow, and that kind is written once and never rewritten. There is no metamorphosis. A verb does not turn into a noun when it finishes. When a verb completes, its state moves and its payload gets written, but its kind stays exactly what it was. The engine enforces this with a single write door for classification, and that door refuses a second entry. This is not a gentle warning about a convention. The refusal itself is what makes the rule true. And the attempt is counted too, so even though nothing changed, anyone checking the count will see that something tried. Think of a birth certificate: you can add notes to a life, but you do not reissue the certificate with a different birthplace. The message names the being and the context. If you see this, look for code that classifies a being a second time and remove that call. Change the state, change the payload, but leave the kind alone.
Text from the Rush engine's error catalogue.