Raised when the LLM's interpret response cannot be parsed against the
structured-output schema — typically because :output_token_budget was too
small and the model's answer truncated mid-list, but also for any other
schema mismatch.
Distinct from RuntimeError so callers can recover (e.g. retry recall with
a larger budget, or surface a typed error to the user) without catching
every internal failure.
See ex-interpret in gralkor/TEST_TREES.md.