Principal AI Engineer

🚀 Principal Software Engineer – Agentic Engineering

📍 Reading | Hybrid

👥 3 positions available.

💰 £100,000 - £120,000

We're looking for three experienced Software Engineers to join a brand-new team.

Using AI and agentic engineering to modernise complex legacy software, and fundamentally change how engineering teams build software.

This isn't a traditional software engineering role.

You won't simply be picking up tickets, writing code and moving onto the next sprint.

You'll be working at the intersection of software engineering, architecture, AI, developer experience and legacy modernisation, helping to design the systems, standards and guardrails that allow engineers to deliver better software safely.

🧠 What will you actually be doing?

You'll be hands-on with some seriously complex legacy technology, using modern AI tooling and engineering practices to tackle technical debt that has often been difficult to address through traditional approaches.

• 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 AI evaluation frameworks (evals) to make sure speed doesn't come at the expense of quality

• Build guardrails, sandboxes and CI/CD controls around AI-driven development

🔧 What background are we looking for?

We're looking for someone who has built a seriously strong software engineering foundation.

You'll ideally have deep experience in C#/.NET, alongside experience working with large, complex or legacy systems.

You might have worked with:

.NET: C#, .NET Framework, ASP.NET, WebForms, MVC, SQL Server, Windows/IIS

We're particularly interested if you've also been working with:

🤖 Claude Code, Cursor, GitHub Copilot, Codex or similar coding agents

🔌 MCP / Model Context Protocol

🧩 Agentic development or AI-assisted software engineering

🧪 Automated testing, evals and quality frameworks

🏗️ Legacy modernisation, major refactoring or framework migrations

☁️ Developer experience, platform engineering or engineering productivity

🌍 Why join?

You'll be joining during a major transformation across Technology, with significant investment in:

• Legacy modernisation

• Public cloud migration

• A next-generation product platform

• AI-enabled software engineering

If these positions are what you may be looking for in a new role, please apply and we'll happily go into more detail!