arXiv subjects

Boris Novikov

Publications and source records attributed to Boris Novikov.

3 recordsLinked to original sources

arXiv2026

When Tool Calls Succeed but Workflows Fail: Anomalies at the Agent-Tool Boundary

AI agents increasingly execute long-running workflows that externalize effects through independently supplied tools. Under retries, speculative execution, concurrency, and partial failures, the resulting external state may be inconsistent with the workflow's intended resolution: required effects may be missing or duplicated, aborted effects may survive, and committed effects may depend on provisional state that is later withdrawn. Advanced transaction models address related failures, but assume that lower-level operations expose the semantics they depend on: whether an effect occurred, whether it can be compensated, staged, or safely reordered. Shared agent-tool interfaces usually do not. We contribute an effect-history model that separates events in the external world from the runtime's observations of them, and a catalog of eight recurring external-effect anomalies. From the catalog we derive the boundary capabilities required to exclude each anomaly in general, and four points where black-box tool invocation alone cannot provide a general guarantee. We then ask how much of this is expressible in a widely used shared tool interface, measuring the use of the standard annotation vocabulary across 98,291 tools exposed by registered Model Context Protocol (MCP) servers. The fields are widely emitted but provide only coarse call-level hints, and none of the required capabilities is fully expressible. These results motivate reusable transactional contracts at the tool boundary.

cs.AI↗

arXiv2019

Delivery, consistency, and determinism: rethinking guarantees in distributed stream processing

Consistency requirements for state-of-the-art stream processing systems are defined in terms of delivery guarantees. Exactly-once is the strongest one and the most desirable for end-user. However, there are several issues regarding this concept. Commonly used techniques that enforce exactly-once produce significant performance overhead. Besides, the notion of exactly-once is not formally defined and does not capture all properties that provide stream processing systems supporting this guarantee. In this paper, we introduce a formal framework that allows us to define streaming guarantees more regularly. We demonstrate that the properties of delivery, consistency, and determinism are tightly connected within distributed stream processing. We also show that having lightweight determinism, it is possible to provide exactly-once with almost no performance overhead. Experiments show that the proposed approach can significantly outperform alternative industrial solutions.

cs.DB↗

arXiv2017

Reflectors and globalizations of partial actions of groups

Given a partial action $θ$ of a group on a set with an algebraic structure, we construct a reflector of $θ$ in the corresponding subcategory of global actions and study the question when this reflector is a globalization. In particular, if $θ$ is a partial action on an algebra from a variety ${\sf V}$, then we show that the problem reduces to the embeddability of certain generalized amalgam of ${\sf V}$-algebras associated with $θ$. As an application, we describe globalizable partial actions on semigroups, whose domains are ideals.

math.CT↗