COPEX: Benchmarking LLM Robustness to Adversarial Context Across Model Context Protocol Layers

Excerpt

arXiv:2610.04378v1 Announce Type: cross Abstract: Large language models increasingly mediate tool use in Model Context Protocol (MCP) systems, where adversarial influence may enter through user instructions, tool schemas, tool outputs, or protocol messages. Existing benchmarks often evaluate deployed agents, conflating model susceptibility with guardrails, orchestration, and general task capability. We introduce COPEX (COntext Provider EXploitation), a controlled benchmark that isolates the mode