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Linguistic Firewall: Geometry as Defense in Multi-Agent Systems Routing

Source

arXiv

arxiv.org/abs/2606.30555v1

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Plain-Language Brief

A new routing architecture called ANTAP (Automatic Non-Textual Agent Picker) was introduced in this research. It aims to address security vulnerabilities in multi-agent systems by discarding indirect proxies and instead using active capability testing to evaluate an agent's true competencies empirically. The system establishes a 'linguistic firewall' that makes metadata-based attacks inexpressible, reducing the attack success rate (ASR) significantly compared to traditional routers.

What the Document Says

  • ANTAP is an evaluation-driven routing architecture introduced for Multi-Agent Systems.
  • It replaces indirect proxies with active capability testing for a more accurate evaluation of an agent's competencies.
  • ANTAP uses a non-textual algebraic projection at inference time, creating a 'linguistic firewall'.
  • The firewall makes metadata-based attacks inexpressible, reducing the attack success rate (ASR).
  • In experiments, ANTAP achieved near-zero ASR against description-based injection attacks compared to 67.3% and above for the description-based router baseline.
  • Against adaptive embedding attacks, ANTAP showed a lower ASR than the embedding-baseline with a 20% reduction.

Key Concepts Mentioned

  • Multi-Agent Systems
  • Routing architecture
  • ANTAP
  • Active capability testing
  • Linguistic firewall
  • Attack success rate (ASR)

Claims Made by the Document

  • ANTAP reduces security vulnerabilities in multi-agent systems.
  • ANTAP achieves near-zero ASR against description-based injection attacks compared to the baseline.
  • ANTAP shows a lower ASR than the embedding-baseline with a 20% reduction against adaptive embedding attacks.

Evidence Used

  • The text describes the introduction and functioning of ANTAP, its improvements over traditional routers, and its performance in experiments.

Methods / Approach

  • Active capability testing
  • Algebraic projection

Limitations Stated by the Authors

UNKNOWN

Limitations Noted by the Agent

Agent interpretation — not from the source.

UNKNOWN

Open Questions

UNKNOWN

Notes for Future Q&A

May include interpretation. Labeled where it does.

UNKNOWN

Raw Abstract / Excerpt

The rapid integration of Large Language Models (LLMs) has driven the evolution of Multi-Agent Systems (MAS), where specialized agents collaborate to execute complex workflows. Effective orchestration in these environments requires robust routing mechanisms to efficiently allocate tasks to the most suitable agent. However, existing routers fundamentally rely on unverified proxies, ranging from textual self-descriptions to static surrogate representations, to gauge an agent's competence. This reliance on non-empirical data creates a critical gap between an agent's projected profile and its actual operational capabilities, introducing severe security vulnerabilities. Malicious agents can easily misrepresent their proficiencies or harbor covert backdoors that evade both standard external analysis and static representation-learning techniques. In this work, we introduce ANTAP (Automatic Non-Textual Agent Picker), an evaluation-driven routing architecture that discards indirect proxies in favor of active capability testing. By dynamically querying agents to ascertain their true competencies empirically, ANTAP distills performance into fixed behavioral operators within a shared semantic space. At inference time, routing is performed via a purely non-textual algebraic projection, establishing a 'linguistic firewall' that renders metadata-based attacks inexpressible. In our experiments, ANTAP achieves near-zero ASR against description-based injection attacks, compared to 67.3% and above for the description-based router baseline. Against adaptive embedding attacks, ANTAP achieves substantially lower ASR than the embedding-based baseline, with a 20% reduction, while remaining resilient to description manipulation by design.