When the Tool Decides: LLM Agents Defer Blindly to Graph Neural Network Tools, and Stronger Backbones Defer More

In three linesLLM agents equipped with GNN tools fail to exercise judgment: they blindly adopt the GNN's predictions 97.6-99.2% of the time. This deference increases with model capability (Qwen2.5 0.5B-7B), creating a 'GNN parrot' that bypasses its own reasoning. Simple alternatives outperform the GNN at high homophily, yet the agent still defers.

Summary generated by Claude — human-verified