Fujitsu has launched a generative artificial intelligence (AI) service that analyses legacy source code, including COBOL, and automatically produces design documents.

IT outlet TechRadar reported on April 4 that the service aims to cut code understanding and documentation work that took hours manually to minutes.

The service is called Fujitsu Application Transform and runs on the company’s in-house generative AI brand, Fujitsu Kozuchi. Fujitsu said it focuses on lowering reliance on specific skilled staff because it can automatically generate design documents without specialist knowledge.

The company said the core is automating the process of understanding legacy code. Fujitsu said it cut the time needed to understand complex source code by about 97 percent by reducing extensive manual review. It said the tool is designed not just to summarise but to help clarify specifications of existing systems and support organisations’ modernisation strategies efficiently.

It also stressed improving document quality. Fujitsu said its solution improves the quality of generated documents compared with analysis using only general-purpose generative AI tools. It applies an "enhanced retrieval" method that links large-scale source code through a knowledge graph to pull related information together and reduce omissions and hallucinations. The company said this improved comprehensiveness by 95 percent and readability by 60 percent.

Fujitsu said these features are particularly important for COBOL. COBOL is a language designed in 1959 by Dr Grace Hopper, and Fujitsu noted there are about 850 billion lines of code worldwide. It is an old language but is still used in core transaction systems at banks, insurers and government agencies, and the possibility of a shortage of COBOL programmers in the United States was raised during the pandemic.

Fujitsu also disclosed user feedback. Toshihiro Horiuchi (호리우치 도시히로), an executive officer at SMBC Nikko Securities, said, "I see this announcement as an initiative that realistically advances legacy system modernisation," adding, "It made me recognise the potential of this technology."

Fujitsu said it plans next steps beyond document generation. It said it will provide support services to help organisations adopt the technology and plans to introduce a function this year to "rebuild" existing source code "for future use". It aims for the system to automatically rewrite code and later support operations and maintenance.

TechRadar said IBM, cited as a key supplier of COBOL-based mainframes and enterprise systems, may need to review its strategy in line with the trend toward automated legacy modernisation.