Sambit Sahu
Author directory2026
A History-Aware Visually Grounded Critic for Computer Use Agents
Jaewoo Lee | Zaid Khan | Archiki Prasad | Justin Chen | Supriyo Chakraborty | Kartik Balasubramaniam | Sambit Sahu | Elias Stengel-Eskin | Hyunji Lee | Mohit Bansal
Findings of the Association for Computational Linguistics: EMNLP 2026
Jaewoo Lee | Zaid Khan | Archiki Prasad | Justin Chen | Supriyo Chakraborty | Kartik Balasubramaniam | Sambit Sahu | Elias Stengel-Eskin | Hyunji Lee | Mohit Bansal
Findings of the Association for Computational Linguistics: EMNLP 2026
Various test-time interventions for Computer Use Agents (CUAs), including critic models, have been developed to improve performance through pre-execution action evaluation in complex Graphical User Interface (GUI) environments. However, existing critics suffer from two key limitations: they (1) focus primarily on short-sighted decision loops (e.g., forgetting earlier actions) and (2) lack the visual grounding needed to detect flawed actions (e.g., clicking wrong UI elements). To address these, we introduce HIVIG, a History-aware Visually Grounded test-time framework, built around a multimodal critic trained on real GUI trajectories to abstract past interactions into a compact record and to evaluate actions with visual grounding. At test time, HIVIG integrates the critic into the policy decision loop to provide macro-action history, which summarizes the policy’s completed achievements, and visually grounded critique, which verifies raw execution coordinates against the current screenshot to intercept errors before execution. Across web, mobile, and desktop benchmarks, HIVIG consistently outperforms existing scalar and verbal critics, improving average success rates over the strongest baseline by 5.8% for Qwen3-VL-32B and 9.0% for Gemini-3-Flash, and demonstrates strong cross-platform generalization. Ablations show that macro-action history mitigates short-sighted planning and visually grounded critique reduces execution errors, with both components being critical for test-time scaling in long-horizon GUI tasks.
AREAs-Lab: An Interactive Environment for AI-driven Requirement Elicitation for AI Systems
Pengshan Cai | Zihao Zhang | Ting Jin | Chenyang Zhu | Kushal Chawla | Sangwoo Cho | Scott Novotney | Yebowen Hu | Fei Liu | Shi-Xiong Zhang | Sambit Sahu
Findings of the Association for Computational Linguistics: EMNLP 2026
Pengshan Cai | Zihao Zhang | Ting Jin | Chenyang Zhu | Kushal Chawla | Sangwoo Cho | Scott Novotney | Yebowen Hu | Fei Liu | Shi-Xiong Zhang | Sambit Sahu
Findings of the Association for Computational Linguistics: EMNLP 2026
Building effective AI systems increasingly depends on writing high-quality task requirements, yet users often struggle to articulate the constraints, preferences, and edge cases that determine success. This problem is especially acute in AI development, where behavior is shaped not only by human expectations but also by data characteristics. We present AREAs-Lab, an interactive environment for AI-driven Requirement Elicitation for AI systems. In AREAs-Lab, an assistant iteratively refines an initially incomplete requirement by analyzing the underlying dataset and asking targeted clarification questions to uncover the user’s latent intent. To study this setting systematically, we construct a synthetic benchmark grounded in 16 public datasets spanning diverse domains and task types. Each benchmark instance includes a user profile, a complete reference requirement, and an intentionally underspecified version that serves as the assistant’s starting point. We further introduce an automated evaluation pipeline based on an AI-simulated user that reveals hidden information only when appropriately prompted, enabling scalable and reproducible assessment of interactive elicitation quality. AREAs-Lab provides a controlled testbed for studying how AI assistants can transform vague user goals into actionable requirements for AI systems.
T1-Bench: Benchmarking Multi-Scenario Agents in Real-World Domains
Genta Indra Winata | Amartya Chakraborty | Yuzhen Lin | Swasthi P Rao | Shikhhar Siingh | Houhan Lu | Nadia Bathaee | Sriharsha Hatwar | Paresh Dashore | Anmol Jain | Kshitij Tayal | Xiuzhu Lin | Anirban Das | Sambit Sahu | Shi-Xiong Zhang
Findings of the Association for Computational Linguistics: EMNLP 2026
Genta Indra Winata | Amartya Chakraborty | Yuzhen Lin | Swasthi P Rao | Shikhhar Siingh | Houhan Lu | Nadia Bathaee | Sriharsha Hatwar | Paresh Dashore | Anmol Jain | Kshitij Tayal | Xiuzhu Lin | Anirban Das | Sambit Sahu | Shi-Xiong Zhang
Findings of the Association for Computational Linguistics: EMNLP 2026
Recent advances in reasoning and tool-calling capabilities of large language models (LLMs) have enabled increasingly capable agentic systems. However, existing benchmarks remain limited in task complexity, realism, and domain diversity, and often fail to capture interactions that span multiple domains, limiting their ability to evaluate agents in realistic multi-step settings that require sustained reasoning and coordination. To address these limitations, we introduce T1-Bench, a high-fidelity, comprehensive benchmark for evaluating agentic systems in realistic customer-facing, multi-domain environments, featuring interleaved scenarios that require structured reasoning across multi-turn user-assistant interactions and substantially increasing both compositional complexity and evaluative rigor across 25 domains of varying difficulty. We evaluate T1-Bench using 12 proprietary and open-weight models, providing a reproducible and standardized framework for assessing agent behavior, tool utilization, and conversational quality in complex, multi-step environments. We further complement automatic evaluation with human judgments to strengthen the assessment of qualitative performance. Overall, T1-Bench substantially advances prior benchmarks by increasing task complexity, interaction depth, and domain coverage in simulated multi-domain environments. To facilitate future research on agentic systems, we will publicly release data and evaluation code as open source.
SPARC-RAG: Adaptive Sequential–Parallel Scaling with Context Management for Retrieval-Augmented Generation
Yuxin Yang | Gangda Deng | Ömer Faruk Akgül | Nima Chitsazan | Yash Govilkar | Akasha Tigalappanavara | Shi-Xiong Zhang | Sambit Sahu | Viktor Prasanna
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Yuxin Yang | Gangda Deng | Ömer Faruk Akgül | Nima Chitsazan | Yash Govilkar | Akasha Tigalappanavara | Shi-Xiong Zhang | Sambit Sahu | Viktor Prasanna
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Retrieval-Augmented Generation (RAG) grounds large language model outputs in external evidence, but remains challenged on multi-hop question answering that requires long reasoning. Recent works scale RAG at inference time along two complementary dimensions: sequential depth for iterative refinement and parallel width for coverage expansion. However, naive scaling causes context contamination and scaling inefficiency, leading to diminishing or negative returns despite increased computation. To address these limitations, we propose SPARC-RAG, a framework that coordinates joint depth–width scaling around a unified context management mechanism—a shared global context state on which specialized control agents regulate parallel exploration and sequential stopping. To optimize scaling behavior, we further introduce a lightweight fine-tuning method with process-level verifiable preferences, which improves the efficiency of sequential scaling and effectiveness of parallel scaling. Across five single- and multi-hop QA benchmarks, SPARC-RAG outperforms the strongest reproduced baseline by an average of 3.8 F1 points at 7B and 9.8 at 32B, with the largest gains on challenging multi-hop tasks.
RECAP: Regression Evaluation for Continual Adaptation of Prompts
Harsh Deshpande | Kushal Chawla | Sangwoo Cho | William M. Campbell | Sambit Sahu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Harsh Deshpande | Kushal Chawla | Sangwoo Cho | William M. Campbell | Sambit Sahu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Production agentic systems routinely face evolving constraints and must comply from the very next interaction. Scenarios like a tool-call notification changing a compliance threshold or a policy update adding disclosure requirements fit this criteria, having close to no room for errors in production. This proactive adaptation setting is common in deployment, but absent from current benchmarks, which assume either static constraint sets or reactive protocols with evaluation feedback. We introduce RECAP, a benchmark that measures continual-learning phenomena (forgetting, regression, forward transfer) at the constraint level under a strictly proactive adapt-then-test protocol: prompt optimization methods receive only the constraint specification and must generalize before seeing any test data. Evaluating six methods across five LLMs and three schedules with evolving constraints, we find that these methods show no significant improvement in performance, even after incurring a higher latency. These methods, designed for offline or reactive settings, are inadequate for the proactive paradigm. Our work emphasizes the growing need for designing proactive prompt adaptation methods, where the models must remain robust to evolving needs in deployment.
Lessons from the Field: An Adaptable Lifecycle Approach to Applied Dialogue Summarization
Kushal Chawla | Chenyang Zhu | Pengshan Cai | Sangwoo Cho | Scott Novotney | Ayushman Singh | Jonah Lewis | Keasha Safewright | Alfy Samuel | Erin Babinsky | Shi-Xiong Zhang | Sambit Sahu
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 5: Industry Track)
Kushal Chawla | Chenyang Zhu | Pengshan Cai | Sangwoo Cho | Scott Novotney | Ayushman Singh | Jonah Lewis | Keasha Safewright | Alfy Samuel | Erin Babinsky | Shi-Xiong Zhang | Sambit Sahu
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 5: Industry Track)
Summarization of multi-party dialogues is a critical capability in industry, enhancing knowledge transfer and operational effectiveness across many domains. However, automatically generating high-quality summaries is challenging, as the ideal summary must satisfy a set of complex, multi-faceted requirements. While summarization has received immense attention in research, prior work has primarily utilized static datasets and benchmarks, a condition rare in practical scenarios where requirements inevitably evolve. In this work, we present an industry case study on developing an agentic system to summarize multi-party interactions. We share practical insights spanning the full development lifecycle to guide practitioners in building reliable, adaptable summarization systems, as well as to inform future research, covering: 1) robust methods for evaluation despite evolving requirements and task subjectivity, 2) component-wise optimization enabled by the task decomposition inherent in an agentic architecture, 3) the impact of upstream data bottlenecks, and 4) the realities of vendor lock-in due to the poor transferability of LLM prompts.
Routing with Generated Data: Annotation-Free LLM Skill Estimation and Expert Selection
Tianyi Niu | Justin Chen | Genta Indra Winata | Shi-Xiong Zhang | Supriyo Chakraborty | Sambit Sahu | Yue Zhang | Elias Stengel-Eskin | Mohit Bansal
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Tianyi Niu | Justin Chen | Genta Indra Winata | Shi-Xiong Zhang | Supriyo Chakraborty | Sambit Sahu | Yue Zhang | Elias Stengel-Eskin | Mohit Bansal
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Large Language Model (LLM) routers dynamically select optimal models for given inputs. Existing approaches typically assume access to ground-truth labeled data, which is often unavailable in practice, especially when user request distributions are heterogeneous and unknown. We introduce Routing with Generated Data (RGD), a challenging setting in which routers are trained exclusively on generated queries and answers produced from high-level task descriptions by generator LLMs. We evaluate query-answer routers (using both queries and labels) and query-only routers across four diverse benchmarks and 12 models, finding that query-answer routers degrade faster than query-only routers as generator quality decreases. Our analysis reveals two crucial characteristics of effective generators: they must accurately respond to their own questions, and their questions must produce sufficient performance differentiation among the model pool. We then show how filtering for these characteristics can improve the quality of generated data. We further propose CASCAL, a novel query-only router that estimates model correctness through consensus voting and identifies model-specific skill niches via hierarchical clustering. CASCAL is substantially more robust to generator quality, outperforming the best query-answer router by 4.6% absolute accuracy when trained on weak generator data.
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Co-authors
- Shi-Xiong Zhang 5
- Kushal Chawla 3
- Sangwoo Cho 3
- Mohit Bansal 2
- Pengshan Cai 2
- Supriyo Chakraborty 2
- Justin Chen 2
- Scott Novotney 2
- Elias Stengel-Eskin 2
- Genta Indra Winata 2
- Chenyang Zhu 2
- Ömer Faruk Akgül 1
- Erin Babinsky 1
- Kartik Balasubramaniam 1
- Nadia Bathaee 1
- William M. Campbell 1
- Amartya Chakraborty 1
- Nima Chitsazan 1
- Anirban Das 1
- Paresh Dashore 1
- Gangda Deng 1
- Harsh Deshpande 1
- Yash Govilkar 1
- Sriharsha Hatwar 1
- Yebowen Hu 1
- Anmol Jain 1
- Ting Jin 1
- Zaid Khan 1
- Hyunji Lee 1
- Jaewoo Lee 1
- Jonah Lewis 1
- Xiuzhu Lin 1
- Yuzhen Lin 1
- Fei Liu 1
- Houhan Lu 1
- Tianyi Niu 1
- Archiki Prasad 1
- Viktor Prasanna 1
- Swasthi P Rao 1
- Keasha Safewright 1
- Alfy Samuel 1
- Shikhhar Siingh 1
- Ayushman Singh 1
- Kshitij Tayal 1
- Akasha Tigalappanavara 1
- Yuxin Yang 1
- Yue Zhang 1
- Zihao Zhang 1