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Refinery

AI tools modernise mainframe code. Refinery proves it is safe to deploy: deterministic checks, a Z3 formal proof and a signed certificate for every AI change to enterprise COBOL. Selected for DiSH at Number 10 North and the IBM Z ScaleUp programme.

September 1, 2025
1 min read
Founder
COBOL
IBM Z
Z3
Python
AI
Refinery 2
Refinery 3

Refinery

AI tools modernise your mainframe code. Refinery proves it is safe to deploy.

An AI tool (watsonx Code Assistant, Copilot, Cursor, any LLM) changes a COBOL program. Refinery diffs the original against the change, runs 11 deterministic checks, a semantic engine and a Z3 formal proof, and produces a signed certificate, a regulatory evidence pack and a sign-off workflow that ends with a named human.

It is not a linter and not a test runner. It is a compliance gate that produces things a regulator can inspect.

Run, Catch, Prove, Explain

  • Run the original and the change side by side
  • Catch the changes regulators care about, with the regulation cited
  • Prove equivalence formally where it holds
  • Explain it in a certificate a risk officer can sign

Backed by

  • DiSH Accelerator, 7th cohort: three months in Manchester, delivered by Plexal with Barclays Eagle Labs, Lancaster University, the University of Manchester and Manchester City Council
  • IBM Z ScaleUp programme
  • Claude Founder House builder cohort
  • Pitched at Pop The Bubble and built on at the IBM Bob Hackathon and Night Shift

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