Title: MMSearch-Plus: Benchmarking Provenance-Aware Search for Multimodal Browsing Agents
Primary area: applications to computer vision, audio, language, and other modalities
Keywords: Large Multimodal Model, AI Search Engine, Benchmark, Agent Framework

Abstract: Existing multimodal browsing benchmarks often fail to require genuine multimodal reasoning, as many tasks can be solved with text-only heuristics without vision-in-the-loop verification. We introduce MMSearch-Plus, a 311-task benchmark that enforces multimodal understanding by requiring extraction and propagation of fine-grained visual cues through iterative image–text retrieval and cross-validation under retrieval noise.
Our curation procedure seeds questions whose answers require extrapolating from spatial cues and temporal traces to out-of-image facts such as events, dates, and venues.
Beyond the dataset, we provide a model-agnostic agent framework with standard browsing tools and a set-of-mark (SoM) module, which lets the agent place marks, crop subregions, and launch targeted image/text searches. SoM enables provenance-aware zoom-and-retrieve and improves robustness in multi-step reasoning.
We evaluated closed- and open-source MLLMs in this framework. The strongest system achieves an end-to-end accuracy of 36.0%, and integrating SoM produces consistent gains in multiple settings, with improvements up to +3.9 points.
From failure analysis, we observe recurring errors in locating relevant webpages and distinguishing between visually similar events. These results underscore the challenges of real-world multimodal search and establish MMSearch-Plus as a rigorous benchmark for advancing agentic MLLMs.

Our dataset is included in the supplementary material and the accompanying code at https://anonymous.4open.science/status/MMSearch-Plus-D54E.

TL;DR: We provide a challenging multimodal browsing benchmark and an agent framework with search tools and Set-of-Mark for provenance-aware zoom-and-retrieve.