Empty
class EmptyLlmResponseException(message: String = "LLM returned an empty or blank response") : RuntimeException
Thrown when an LLM call returns an empty or blank response where text was expected. Distinct from a generic IllegalArgumentException so callers can recognise the case and substitute a friendlier prompt (e.g. "I don't have a response — could you rephrase?") rather than leak a technical error message.
Common with weaker open-weights chat models that occasionally go silent after a tool call. Catch by type — do NOT pattern-match on e.message, which is brittle.