What to Remember, What to Reveal: Privacy-Aware Memory for Conversational Agents

AuthorsWenjie Wang, Wenhe Si, Xinyue Xu, Yue Xu

arXiv 20262026

TL;DR

SP-Mem decouples sanitized memory from protected private values, enabling privacy-aware retrieval while keeping privacy-entity identification at 0.996 accuracy and unnecessary exposure as low as 0.33%.

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THE PROBLEM

Long-term agents leak PII even when tasks only need preferences

SP-Mem targets memory systems that optimize utility but neglect privacy, even though privacy-entity identification can reach 0.996 accuracy with careful design.

In dinner recommendation or form-filling tasks, long-term conversational agents may retrieve and expose home addresses or other PII, creating persistent privacy risk across sessions.

HOW IT WORKS

SP-Mem — Sanitized Privacy-Mapped Memory

SP-Mem combines Privacy-Aware Memory Writing, Partitioned Storage with Privacy Mapping, and Privacy-Aware Query-Time Reasoning and Authorized Retrieval over complementary vector and graph memory.

You can think of SP-Mem like a library card catalog: sanitized entries stay searchable on open shelves, while exact private values are locked in a vault linked only by keys.

This design lets SP-Mem retrieve rich personalized context beyond a plain context window while restoring exact private values only when tasks require them and users grant consent.

DIAGRAM

Query-Time Privacy-Aware Reasoning Flow

This diagram shows how SP-Mem analyzes a query, decides if private values are needed, and conditionally hydrates them under user consent.

DIAGRAM

Privacy-Aware Benchmark Construction Pipeline

This diagram shows how SP-Mem's benchmark generates user profiles, subtasks, history dialogues, and test queries.

PROCESS

How SP-Mem Handles a Conversation Session

  1. 01

    Privacy-Aware Memory Writing

    SP-Mem uses Privacy-Aware Memory Writing to convert user utterances into facts and relation triplets while tagging private values with the privacy-entity taxonomy.

  2. 02

    Partitioned Storage with Privacy Mapping

    SP-Mem applies Partitioned Storage with Privacy Mapping to store sanitized facts in vector and graph stores and exact private values in a protected private store linked by mapping keys.

  3. 03

    Privacy-Aware Query-Time Reasoning and Authorized Retrieval

    SP-Mem runs Privacy-Aware Query-Time Reasoning and Authorized Retrieval to decide if private entities are required, request consent, and selectively hydrate exact values via the privacy mapping layer.

  4. 04

    Response Generation

    SP-Mem performs response generation using the current query, sanitized memories, and any authorized exact private values to complete tasks while respecting privacy constraints.

KEY CONTRIBUTIONS

Key Contributions

  • 01

    Sanitized Privacy-Mapped Memory Architecture

    SP-Mem introduces a Sanitized Privacy-Mapped Memory architecture combining Privacy-Aware Memory Writing, Partitioned Storage with Privacy Mapping, and Privacy-Aware Query-Time Reasoning and Authorized Retrieval over hybrid vector plus graph memory.

  • 02

    Privacy-Aware Memory Benchmark

    SP-Mem comes with a privacy-aware memory benchmark of 1,000 user profiles, 21,000 history dialogues, and 54,000 user-query evaluation instances across finance, medical, education, and mental support domains.

  • 03

    Joint Evaluation of Utility and Privacy

    SP-Mem provides an evaluation pipeline that measures response quality, personalization, privacy behavior, and token cost, including metrics like Unnecessary Privacy Usage dropping to 0.33% on preference-only tasks.

RESULTS

By the Numbers

Privacy-entity identification accuracy

0.996

overall accuracy across domains for SP-Mem privacy-aware memory writing

Privacy-entity identification recall

0.992

recall across domains for SP-Mem privacy-aware memory writing

Privacy-entity identification precision

0.965

precision across domains for SP-Mem privacy-aware memory writing

Preference-only UPU rate

0.33%

exact private exposure on preference-only tasks for SP-Mem vs 16.00% for Full-context

The privacy-aware benchmark tests SP-Mem on 2,100 history dialogues and 5,400 queries, measuring privacy-entity identification and Unnecessary Privacy Usage. These results show that SP-Mem accurately detects private entities while sharply reducing unnecessary exposure compared to Full-context prompting.

BENCHMARK

By the Numbers

The privacy-aware benchmark tests SP-Mem on 2,100 history dialogues and 5,400 queries, measuring privacy-entity identification and Unnecessary Privacy Usage. These results show that SP-Mem accurately detects private entities while sharply reducing unnecessary exposure compared to Full-context prompting.

BENCHMARK

Unnecessary Privacy Usage on Preference-only Tasks

Unnecessary Privacy Usage rate when tasks require only preferences and no private information.

KEY INSIGHT

The Counterintuitive Finding

SP-Mem keeps Unnecessary Privacy Usage on preference-only tasks at just 0.33%, while Full-context prompting leaks exact private values in 16.00% of responses.

This is surprising because many assume more context always helps personalization, but SP-Mem shows that trimming exact private values can improve safety without hurting task completion.

WHY IT MATTERS

What this unlocks for the field

SP-Mem unlocks long-term conversational agents that remember rich user preferences while tightly controlling when exact private values are stored, retrieved, and revealed.

Builders can now deploy memory-augmented assistants that support tasks like finance and medical help with explicit consent gates, rather than relying on brittle prompt-time sanitization.

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