Cumulative and Audited Guardrail Tool Evolution for LLM Agent Safety

Key points

• The authors propose EVOLVE, a four-stage framework that externalizes security knowledge into executable guardrail tools which are inherited, audited, and repaired, to address the weakness of fixed-rule defenses against emerging risks.
• Six specialized agents cover risk analysis, tool generation, tool fusion, execution, auditing, and revision, forming a closed loop from risk perception to trusted adaptation.
• Across the RJudge, ASSEBench, and AgentHarm benchmarks and four backbone LLMs, EVOLVE ranks first in all 12 combinations and outperforms existing defenses by +22% average F1 score.
• The authors identify the VGT phenomenon in which over 20% of initially generated tools contain vulnerabilities, and auditing lowers the risky-tool share in the programming domain from 44.78% to 8.20%.
• EVOLVE achieves 93.3% accuracy in detecting risks in the embodied AI2THOR environment, and on a real 6-DoF robotic arm it blocks sharp-object and falling-object hazards and replans paths to avoid collisions.
• Guardrail tool reuse rates reach up to 86%, showing that security knowledge accumulates and evolves through interaction rather than remaining fixed after deployment.

Paper links

External research summaries. These are not HDATF publications or measured product results.