AI-Powered Legacy Modernization Engineer

RedRock Resourcing; Reading; On-site; GBP 65,000 - 95,000; Full time

Job summary

RedRock Resourcing is seeking a software engineer who operates at the intersection of software engineering, architecture, AI and legacy modernization to help design the systems, standards and guardrails that allow engineers to deliver better software safely.

You’ll be hands-on with complex legacy tech, using modern AI tooling to tackle debt and perform refactors, while building the engineering harness, prompts and context that guide AI agents.

Qualifications

• Strong software engineering foundation in C#/.NET.
• Experience with large, complex or legacy systems.
• Experience with AI-assisted software engineering and agentic development.

Responsibilities

• Use AI coding agents to investigate, refactor and modernise legacy codebases.
• Design the engineering harness that gives AI agents the right context, rules and constraints to work effectively.
• Build repository-level instructions, agent skills, prompts and dynamic context.
• Work with technologies such as Claude Code, MCP and other agentic development tools.
• Establish automated testing and evals to maintain quality while increasing speed.
• Build guardrails, sandboxes and CI/CD controls around AI-driven development.

Skills

C#/.NET

AI tooling

Legacy systems

Tools

Claude Code

GitHub Copilot

Codex

Job description

RedRock Resourcing is seeking a software engineer who operates at the intersection of software engineering, architecture, AI and legacy modernization to help design the systems, standards and guardrails that allow engineers to deliver better software safely.

You’ll be hands-on with complex legacy tech, using modern AI tooling to tackle debt and perform refactors, while building the engineering harness, prompts and context that guide AI agents.