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arXiv · 2605.11360

Options, Not Clicks: Lattice Refinement for Consent-Driven MCP Authorization

Abstract

As Model Context Protocol adoption grows, securing tool invocations via meaningful user consent has become a critical challenge, as existing methods, broad always allow toggles or opaque LLM-based decisions, fail to account for dangerous call arguments and often lead to consent fatigue. In this work, we present Conleash, a client-side middleware that enforces boundary-scoped authorization by utilizing a risk lattice to auto-permit safe calls within known boundaries while escalating risks, a policy engine for user-defined invariants, and a refinement loop that converts user decisions into reusable rules. Evaluated on 984 real-world traces, Conleash achieved 98.2% accuracy, caught 99.4% of escalations, and added only 8.2 ms of overhead for policy verification; furthermore, in a user study where N=16, participants significantly preferred Conleash scoped permissions over traditional methods, citing higher trust and reduced prompting.

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Ying Li, Yanju Chen, Peiran Wang, Issac Khabra, Faysal Hossain Shezan, Yu Feng, Yuan Tian. 2026-05-12. Options, Not Clicks: Lattice Refinement for Consent-Driven MCP Authorization. https://arxiv.org/abs/2605.11360

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