Log analysis is necessary for credible evaluation of AI agents

Computer Science > Artificial Intelligence [Submitted on 8 May 2026] Log analysis is necessary for credible evaluation of AI agents Peter Kirgis, Sayash Kapoor, Stephan Rabanser, Nitya Nadgir, Cozmin Ududec, Magda Dubois, JJ Allaire, Conrad Stosz, Marius Hobbhahn, Jacob Steinhardt, Arvind Narayanan Agent benchmarks typically report only final outcomes: pass or fail. This threatens evaluation credibility in three ways. First, scores may be inflated or deflated by shortcuts and benchmark artifacts, misrepresenting capability. Second, benchmark performance may fail to predict real-world utility due to scaffold limitations and recurring failure modes. Finally, capability scores may conceal dangerous or catastrophic actions taken by the agent. We argue that log analysis -- the systematic tracking and analysis of the inputs, execution, and outputs of an AI agent -- is necessary to overcome these validity threats and promote credible agent evaluation. In this paper, we (1) present a taxonomy of threats to credible evaluation documented through log analysis, and (2) develop a set of guiding principles for log analysis. We illustrate these principles on tau-Bench Airline, revealing that pass^5 performance was under-elicited by nearly 50% and surfacing deployment failure modes invisible to outcome metrics. We conclude with pragmatic recommendations to increase uptake of log analysis, directed at diverse stakeholders including benchmark creators, model developers, independent evaluators, and deployers. Subjects: Artificial Intelligence (cs.AI) Cite as: arXiv:2605.08545 [cs.AI]   (or arXiv:2605.08545v1 [cs.AI] for this version)   https://doi.org/10.48550/arXiv.2605.08545 Focus to learn more Submission history From: Peter Kirgis [view email] [v1] Fri, 8 May 2026 23:10:32 UTC (71 KB) Access Paper: HTML (experimental) view license Current browse context: cs.AI < prev   |   next > new | recent | 2026-05 Change to browse by: cs References & Citations NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)