Safeguards for Speech2Speech LLM-Assistants: A Case Study in Automotive Applications
Abstract
Recent advances have introduced speech-to-speech (S2S) conversational assistants capable of producing natural-sounding interactions, including non-verbal cues like tonality and mood. In the automotive domain, this enables intuitive and humanlike in-car dialogue experiences. However, integrating these end-to-end assistants limits architectural options for programmable domain-specific safeguards. This paper discusses two implementation approaches for S2S guardrails: transcript-based and tool-based. Through an empirical evaluation, we demonstrate that both strategies are insufficient for industrial deployment in most cases due to prohibitive latency (delaying each answer by 0 to 1.4 seconds even for computationally cheap checks) and technical impediments (like potentially non-deterministic tool call behavior). Finally, we outline open challenges for S2S guardrails in the automotive context.
Keywords
Cite
@article{arxiv.2607.21180,
title = {Safeguards for Speech2Speech LLM-Assistants: A Case Study in Automotive Applications},
author = {Gregor Endler and Sebastian Kraus and Lukas Stappen},
journal= {arXiv preprint arXiv:2607.21180},
year = {2026}
}