arXiv AI

STRIATUM-CTF: A Protocol-Driven Agentic Framework for Autonomous CTF Solving

STRIATUM-CTF is a modular agentic framework that uses the Model Context Protocol to mediate between large language model reasoning and the execution of offensive‑security tools. By exposing tools as strictly typed, schema‑validated functions, the protocol rejects invalid tool calls and returns structured observations that the agent can use to self‑correct. In controlled experiments the system achieved 77.8–86.7% success across 15 CTF challenges, and in a live multi‑team CTF at Florida State University it placed first among more than 30 teams.

arXiv AI
Oct 19

Action-Space Shaping for LLM Agents: Measuring and Mitigating Tool-Schema Bias

The paper investigates how the representation of tool interfaces—referred to as a tool schema—affects the performance of large language model agents. By systematically transforming a native tool schema with nine operators, the authors demonstrate that agents exhibit significant variability in success rates across different but functionally equivalent schema variants, a phenomenon they call schema bias. Experiments on eleven LLMs, including closed models, reveal that success can range from complete failure to 97% solely due to schema differences, and that training only mitigates bias when the specific variant is included in the training data.

By Yinhong Liu, Zhili Tan, Zilin Wang, Zhijiang Guo
arXiv AI
Jul 14

AgentAbstain: Do LLM Agents Know When Not to Act?

arXiv:2607. 10059v1 Announce Type: new Abstract: Agent systems based on large language models (LLMs) are increasingly deployed for autonomous tasks, yet existing evaluations mostly focus on task success rather than whether agents know when to abstain.

By Xun Liu, Yi Evie Zhang, Vira Kasprova, Parisa Rabbani, Pardis Sadat Zahraei, Tianyu Zhang, Ali Ebrahimpour-Boroojeny, Varun Chandrasekaran
arXiv AI
Oct 26

Mining the Design Space of Multi-Agent Workflows

The paper introduces a two‑phase pipeline that mines reproducible design principles for large language model multi‑agent systems by reusing all intermediate search trajectories from an MCTS optimizer. Using six composable operators and 26 Enigmata tasks, the authors generate a corpus of 28,568 executable workflows and apply an AutoResearch loop to discover and validate orchestration patterns. Key findings include that Star‑first workflows underperform, SharedMemory outperforms debate, and prompt specificity and placeholder‑based routing provide comparable gains to communication‑structure selection.

By Xavier Cadet, Junyan Cheng, Peter Chin, Kyle Richardson
arXiv AI
Oct 28

Log-To-Leak: Prompt Injection Attacks on Tool-Using LLM Agents via the Model Context Protocol

The paper "Log-To-Leak: Prompt Injection Attacks on Tool-Using LLM Agents via the Model Context Protocol" investigates how natural-language metadata in the Model Context Protocol (MCP) can be exploited to inject malicious post‑hoc logging calls into large language model agents. The authors introduce the Log-To-Leak attack, which adds an attacker‑controlled call after a legitimate tool invocation, targeting user queries, MCP server names, server responses, and agent responses. Experiments across five MCP servers and four LLM agents show high attack success rates (up to 100%) and significant logging accuracy, while existing defenses still leave substantial residual risk.

By Yuepeng Hu, Chongyu Fan, Sirat Samyoun, Jian Du
arXiv AI
Sep 17

Symbolic Temporal Supervision of LLM Agents Using Contracts

ContrAgent is a contract‑based framework that provides symbolic temporal supervision for large language model agents. It records an agent’s tool‑call sequence as a trace of checkable predicates and formalizes desired behaviors with assume‑guarantee contracts expressed in linear temporal logic over finite traces (LTLf). Each contract is compiled into a deterministic finite automaton that both gates actions online and evaluates recorded traces offline, enabling deterministic, reproducible verdicts and significantly lower per‑call latency compared to existing LLM‑judge and rule‑based guardrail baselines.

By Yifeng Xiao, Pierluigi Nuzzo