The Prompt Is the Architecture: HRIS Constraints Reconstruct Epistemic Discipline Without Cross-Session Memory

This study examines whether HRIS-consistent epistemic reasoning behavior is dependent on cross-session user memory features or whether it can be reconstructed from prompt-level constraint structure alone. A 2x2 behavioral design was employed, crossing user-level memory condition (memory-enabled vs. memory-disabled) with reasoning mode (HRIS-constrained vs. baseline), producing four experimental conditions across 40 independent runs distributed over 10 days. Five standardized underdetermined prompts spanning medical, legal, employment, and attribution domains were administered in newly initiated chats under each condition. Responses were scored on a five-dimension behavioral rubric assessing uncertainty calibration, hallucination resistance, structural reasoning discipline, premature closure resistance, and cross-run consistency, with a maximum composite score of 15. Results show that HRIS-constrained prompting produced large improvements in reasoning quality under both memory conditions. The memory-disabled HRIS condition scored 12.00/15 compared to 7.30/15 for the memory-disabled baseline, a delta of 4.70 points. The memory-enabled HRIS condition scored 13.50/15 compared to 8.60/15 for the memory-enabled baseline, a delta of 4.90 points. The effect of memory alone, holding reasoning mode constant, was 1.50 points under HRIS conditions and 1.30 points under baseline conditions. These findings indicate that the HRIS effect is substantially larger than the memory effect and remains nearly unchanged when memory is disabled. These results support a constraint-driven reconstruction account of stable AI reasoning behavior and argue against a product-level persistence account. HRIS-consistent epistemic discipline does not require cross-session memory to manifest; it is reconstructable from prompt architecture alone in each fresh session. The implications extend to any high-stakes deployment context where session continuity cannot be assumed, including clinical decision support, legal analysis, and structured diagnostic reasoning. A secondary finding identifies a prompt-content interaction in the attribution-under-uncertainty condition, where HRIS-constrained runs showed reduced premature closure resistance compared to other prompt types, suggesting that certain inferential tasks may resist indeterminate framing in ways warranting further investigation.