Cognitive Exoskeletons for Human-AI Interaction: Nexus Architecture, Token Density, Strategic Coherence, and Extended Applied Benchmarking

Large language models (LLMs) have reached a level of fluency and generality that allows them to assist in complex intellectual work. However, most human–AI interaction remains session-bound, shallow, and structurally unstable. This paper introduces the concept of a cognitive exoskeleton: a persistent, externalized meta-structure that governs how a human and an AI system reason together over time.