This document defines the LLM INQUISITOR METHODOLOGY: a structured, repeatable discipline for evaluating the behaviour of large language models under controlled load. It provides a formal approach for assessing reliability through observable behaviour and evidentiary traceability. The methodology is designed to support rigorous evaluation in research, safety, and enterprise assurance contexts, where behavioural stability under real operational conditions is a critical requirement. Project website: https://assimilatedhuman.github.io/inquisitor-labs/