Error message
In the message, %s marks a value that the engine fills in when it raises the error.
The story
The engine refused to start, and the message mentions the Trinity vocabulary. Here is the short version. Every being in rush is exactly one of three kinds: a noun, a verb, or a flow. Nobody declares the kind. It is derived from one question: does executing this thing produce a value? The possible answers, and the kind each answer leads to, are written in trinity.feml. This time, that file could not be used. It could not be read, or it declared no answers, or its affirmative answer pointed at nothing that exists. Without it, the engine has no way to turn an answer into a kind, and the rule that only verbs produce values has nothing to stand on. Imagine a sorting machine whose label chart is missing: every package is a guess. The engine could fall back on a default hidden in the code, but that would be a second criterion, and the design says there is exactly one. So it stops. The message gives you the path and the reason. Open trinity.feml, make sure it is readable, and make sure every answer it names is declared. Then start again.
Text from the Rush engine's error catalogue.