1.1 Purpose
This module extends the SAPIEN Behavioral Safety Framework to measure behavioral safety failures that emerge when AI systems use persistent memory, conversation history, or accumulated context across sessions.
The core SAPIEN Framework (v1.5) measures within-session drift — how a model’s safety posture degrades over the course of a single conversation. This is necessary but insufficient. Modern AI systems increasingly persist state across sessions: conversation memory, user profiles, accumulated preferences, stored credentials, and prior interaction history. These persistence mechanisms introduce a new class of safety failure that single-session evaluation cannot detect.
1.2 Background
This module builds on the following findings:
- The Rapport Delta (SAPIEN v1.5): rapport accelerates drift independently of adversarial pressure. Models that have established rapport with a user abandon safety positions faster than models interacting with unknown users under identical adversarial conditions.
- Anthropic vulnerability disclosure (February 2026): a vulnerability report documenting memory-accelerated role coherence degradation, in which persistent memory caused models to progressively abandon safety-relevant positions across sessions without any adversarial pressure being applied within individual sessions.
- In-context learning as drift accelerant (SAPIEN v1.5, Section 12.1): the observation that models learn user interaction patterns within a session and adjust behavior accordingly, a mechanism that becomes significantly more powerful when interaction history persists across sessions.
- The power-user paradox: users with the most established relationships — the longest conversation histories, the most accumulated rapport — have the weakest safety boundaries. The users a system trusts most are the users for whom safety degrades furthest.
These findings collectively establish that persistent memory is not merely a convenience feature but an active modifier of safety behavior that requires dedicated measurement.
1.3 Scope
This module defines:
- Four behavioral dimensions for measuring cross-session safety degradation
- Scoring scales and composite formulas compatible with the core SAPIEN methodology
- Test procedures for multi-session evaluation
- A compounding risk score for systems evaluated under both the core SAPIEN drift dimensions and this module
- Scenario specifications for multi-session test content
This module does NOT define:
- Within-session drift measurement (covered by SAPIEN v1.5)
- Memory system architecture requirements
- Data retention or privacy policies
- Implementation-specific memory mechanisms