Control of Intent Routing in Agentic Commerce

Agentic-commerce discussions increasingly contrast open networks of specialized execution agents with vertically integrated or exclusive platform ecosystems. This paper studies that contrast as an industrial-organization problem. It models an upstream assistant platform that captures a stream of user intents and chooses among three routing regimes: an open order-flow auction (OFA), an exclusive bundle contract, or, when the platform has in-house execution capacity, a Mixed regime that integrates the top quantile of intents and routes the residual flow to OFA. The paper’s main positive contribution is a Levin-Smith cream-skimming theorem. Under the residual period-cost convention and explicit sufficient conditions on solver cost dispersion, residual entry, and contractor productivity, the Mixed regime strictly dominates the open, exclusive, and random-selection integration benchmarks on a non-empty open set of primitives. A setup lemma and one supporting theorem frame the comparison. Lemma 1A gives a standard endogenous-entry bound for no-reserve OFA revenue. Theorem 2A gives a high-entry exclusivity-dominance result under Levin-Smith mixed-strategy entry: exclusivity strictly dominates open routing whenever exclusive bundle revenue exceeds expected open-routing revenue. The pure-entry rule recovers the discrete e > pi(2) collapse threshold as a corollary. Numerical calibration to payment for order flow and MEV/OFA on Ethereum finds entry-cost-to-margin ratios far below the model’s dominance thresholds. The theorems are therefore pressure tests of routing control rather than predictions about those specific markets. A screening calculation for regulated fiat-payment routing gives a plausible entry-cost-to-margin band of e/pi(2) = O(1)–O(10) when platform-specific compliance and liability costs bind, but this remains a threshold sketch rather than a measured empirical validation.