@inproceedings{de-raedt-etal-2026-coral,
title = "{CORAL}: Closed-loop Oracle Alignment for Agentic Tax Engine Modernization",
author = "De Raedt, Maarten and
Abdullah, Ahmed and
Agrawal, Abhinav",
editor = "Huang, Jimin and
Lee, Yongjae and
Ananiadou, Sophia and
Chen, Hsin-Hsi and
Takamura, Hiroya and
Chen, Chung-Chi",
booktitle = "Proceedings of the 11th Workshop on Financial Technology and Natural Language Processing",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.finnlp-1.15/",
pages = "180--192",
ISBN = "979-8-89176-466-8",
abstract = "Modernizing legacy software is often framed as code migration, an approach that assumes access to source code and an understanding of system internals. In practice these assumptions fail: source may be inaccessible, data in proprietary formats, and documentation dispersed. We study an underexplored regime in which a replacement is aligned to a legacy system treated as a black-box oracle, using only its input{--}output behavior.\par We present CORAL (Closed-loop Oracle Alignment), an agentic framework that aligns a modern U.S. individual income tax engine (Form 1040) to a production oracle (a system built over decades) by iteratively refining LLM-bootstrapped form schemas. Each round runs a scenario on both systems, compares e-file output field-by-field, and diagnoses discrepancies against an authoritative IRS knowledge base (KB), grounding every fix in published regulation rather than relying on model knowledge. An edit is kept only if re-execution shows no meaningful field-level $F_1$ regression and all tests pass, a deterministic check rather than model self-assessment. Round-robin sequencing over under-covered forms then reaches the long tail of forms, not just the high-frequency ones a taxpayer shares with everyone.\par Across 119 tax-expert-authored scenarios, each a complete taxpayer return, CORAL repairs defects from single-field corrections to reviving entire non-functional forms (53 fixed; 13 escalated to human review, ensuring ambiguous rules and input-data gaps are audited manually), lifting macro-$F_1$ on a 30-scenario held-out test split, averaged over returns, from an LLM-bootstrapped start (0.17) to 0.90."
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<abstract>Modernizing legacy software is often framed as code migration, an approach that assumes access to source code and an understanding of system internals. In practice these assumptions fail: source may be inaccessible, data in proprietary formats, and documentation dispersed. We study an underexplored regime in which a replacement is aligned to a legacy system treated as a black-box oracle, using only its input–output behavior.\par We present CORAL (Closed-loop Oracle Alignment), an agentic framework that aligns a modern U.S. individual income tax engine (Form 1040) to a production oracle (a system built over decades) by iteratively refining LLM-bootstrapped form schemas. Each round runs a scenario on both systems, compares e-file output field-by-field, and diagnoses discrepancies against an authoritative IRS knowledge base (KB), grounding every fix in published regulation rather than relying on model knowledge. An edit is kept only if re-execution shows no meaningful field-level F₁ regression and all tests pass, a deterministic check rather than model self-assessment. Round-robin sequencing over under-covered forms then reaches the long tail of forms, not just the high-frequency ones a taxpayer shares with everyone.\par Across 119 tax-expert-authored scenarios, each a complete taxpayer return, CORAL repairs defects from single-field corrections to reviving entire non-functional forms (53 fixed; 13 escalated to human review, ensuring ambiguous rules and input-data gaps are audited manually), lifting macro-F₁ on a 30-scenario held-out test split, averaged over returns, from an LLM-bootstrapped start (0.17) to 0.90.</abstract>
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%0 Conference Proceedings
%T CORAL: Closed-loop Oracle Alignment for Agentic Tax Engine Modernization
%A De Raedt, Maarten
%A Abdullah, Ahmed
%A Agrawal, Abhinav
%Y Huang, Jimin
%Y Lee, Yongjae
%Y Ananiadou, Sophia
%Y Chen, Hsin-Hsi
%Y Takamura, Hiroya
%Y Chen, Chung-Chi
%S Proceedings of the 11th Workshop on Financial Technology and Natural Language Processing
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-466-8
%F de-raedt-etal-2026-coral
%X Modernizing legacy software is often framed as code migration, an approach that assumes access to source code and an understanding of system internals. In practice these assumptions fail: source may be inaccessible, data in proprietary formats, and documentation dispersed. We study an underexplored regime in which a replacement is aligned to a legacy system treated as a black-box oracle, using only its input–output behavior.\par We present CORAL (Closed-loop Oracle Alignment), an agentic framework that aligns a modern U.S. individual income tax engine (Form 1040) to a production oracle (a system built over decades) by iteratively refining LLM-bootstrapped form schemas. Each round runs a scenario on both systems, compares e-file output field-by-field, and diagnoses discrepancies against an authoritative IRS knowledge base (KB), grounding every fix in published regulation rather than relying on model knowledge. An edit is kept only if re-execution shows no meaningful field-level F₁ regression and all tests pass, a deterministic check rather than model self-assessment. Round-robin sequencing over under-covered forms then reaches the long tail of forms, not just the high-frequency ones a taxpayer shares with everyone.\par Across 119 tax-expert-authored scenarios, each a complete taxpayer return, CORAL repairs defects from single-field corrections to reviving entire non-functional forms (53 fixed; 13 escalated to human review, ensuring ambiguous rules and input-data gaps are audited manually), lifting macro-F₁ on a 30-scenario held-out test split, averaged over returns, from an LLM-bootstrapped start (0.17) to 0.90.
%U https://aclanthology.org/2026.finnlp-1.15/
%P 180-192
Markdown (Informal)
[CORAL: Closed-loop Oracle Alignment for Agentic Tax Engine Modernization](https://aclanthology.org/2026.finnlp-1.15/) (De Raedt et al., FinNLP 2026)
ACL