Modernizing legacy VB6 batch processing with AI agents
2026 - present · VB6, Java 25, Spring Batch, Spring Boot 4, REST, MCP, SSH
Problem
Legacy VB6 batch processes at Techne, whose volume had made a rewrite unfeasible for years, the kind of project that used to sit in a drawer.
Approach
I structured the work for AI agents: a versioned architectural contract in the repository, access to the real database via MCP, and characterization tests that run the original VB binary via SSH to generate the fixtures the Java code must reproduce, keeping 1:1 parity with the original system.
Technology
VB6 (legacy), Spring Batch, Java 25, Spring Boot 4, REST, MCP, SSH, characterization tests, AI agents.
Result
Unlocked a modernization that had been stalled for years. 1:1 parity with the original system, exposed via REST.