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Main Authors: Apparaju, Sreeja, Gupta, Nilesh
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2603.14635
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author Apparaju, Sreeja
Gupta, Nilesh
author_facet Apparaju, Sreeja
Gupta, Nilesh
contents As agents operate over long horizons, their memory stores grow continuously, making retrieval critical to accessing relevant information. Many agent queries require reasoning-intensive retrieval, where the connection between query and relevant documents is implicit and requires inference to bridge. LLM-augmented pipelines address this through query expansion and candidate re-ranking, but introduce significant inference costs. We study computation allocation in reasoning-intensive retrieval pipelines using the BRIGHT benchmark and Gemini 2.5 model family. We vary model capacity, inference-time thinking, and re-ranking depth across query expansion and re-ranking stages. We find that re-ranking benefits substantially from stronger models (+7.5 NDCG@10) and deeper candidate pools (+21% from $k$=10 to 100), while query expansion shows diminishing returns beyond lightweight models (+1.1 NDCG@10 from weak to strong). Inference-time thinking provides minimal improvement at either stage. These results suggest that compute should be concentrated on re-ranking rather than distributed uniformly across pipeline stages.
format Preprint
id arxiv_https___arxiv_org_abs_2603_14635
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Compute Allocation for Reasoning-Intensive Retrieval Agents
Apparaju, Sreeja
Gupta, Nilesh
Information Retrieval
Artificial Intelligence
As agents operate over long horizons, their memory stores grow continuously, making retrieval critical to accessing relevant information. Many agent queries require reasoning-intensive retrieval, where the connection between query and relevant documents is implicit and requires inference to bridge. LLM-augmented pipelines address this through query expansion and candidate re-ranking, but introduce significant inference costs. We study computation allocation in reasoning-intensive retrieval pipelines using the BRIGHT benchmark and Gemini 2.5 model family. We vary model capacity, inference-time thinking, and re-ranking depth across query expansion and re-ranking stages. We find that re-ranking benefits substantially from stronger models (+7.5 NDCG@10) and deeper candidate pools (+21% from $k$=10 to 100), while query expansion shows diminishing returns beyond lightweight models (+1.1 NDCG@10 from weak to strong). Inference-time thinking provides minimal improvement at either stage. These results suggest that compute should be concentrated on re-ranking rather than distributed uniformly across pipeline stages.
title Compute Allocation for Reasoning-Intensive Retrieval Agents
topic Information Retrieval
Artificial Intelligence
url https://arxiv.org/abs/2603.14635