tool-augmented language agents

Ghost Tool Calls: Issue-Time Privacy for Speculative Agent Tools

This paper identifies a privacy vulnerability in tool-augmented language agents that speculatively issue future tool calls to reduce latency: these 'ghost tool calls' leak inferred user intent to external services before the agent commits to a branch, and cannot be unsent after the fact. The authors argue that timing—not authorization—is the core issue, and propose Speculative Tool Privacy Contracts, a runtime abstraction treating pre-commitment observation as a distinct first-class effect. A prototype runtime is implemented and twelve policies are evaluated across three corpora, finding that only issue-time argument or destination suppression/modification actually reduces inference leakage.