Agentic AI Engineer

Sanderson; West of England; Hybrid; GBP 120,000 - 166,000; Full time

Job summary

Sanderson is seeking a contractor to design and build AI agents that generate production-grade .NET code. You will implement a spec-driven workflow and establish review gates, integrating tools via MCP while upskilling the team on agentic patterns.

We require a strong .NET background (ASP.NET Core) and hands-on experience with agent frameworks. This is a hybrid Bristol-based role with a 6-month+ programme and potential extension.

Qualifications

• Contractor with proven track record shipping AI agents in production.
• Strong .NET background with hands-on experience in ASP.NET Core.
• Experience implementing spec-driven development workflows.
• Ability to design review gates and verification for agent outputs.

Responsibilities

• Design and build agents that produce production-grade .NET code.
• Implement a spec-driven development workflow (spec, plan, tasks, implement).
• Build review and approval gates for agent output before merge.
• Integrate tools and data sources via MCP.
• Set up evaluation, guardrails and tests to catch incorrect output early.
• Upskill the engineering team on agentic patterns and spec-driven approach.
• Proven track record shipping AI agents in production, including tool calling and orchestration.
• Work with .NET 8/9 and ASP.NET Core.
• Hands-on with a .NET-native agent framework such as Microsoft Agent Framework or Semantic Kernel.

Skills

.NET

C#

ASP.NET Core

Semantic Kernel

Microsoft Agent Framework

Spec Kit

MCP

AI agents

Code validation

Review gates

Tools

Semantic Kernel

Spec Kit

MCP

ASP.NET Core

Job description

• Client: Global Technology Leader – NASDAQ Listed
• Location: Hybrid — Bristol / 3 Days Per Week
• Duration: 6 months + Intention to extend (Greenfield Multi-Year Programme)

Our client, a global leader in software systems, is building AI agents that generate production .NET code under developer supervision. The goal of this greenfield is a spec-driven pipeline where a specification and technical plan drive what the agent builds, and a developer reviews and validates the output at every stage before it ships.

We are looking for a contractor who has built and shipped AI agents in production and who brings a strong .NET background. This is a hands-on engineering role with scope to set the technical direction and bring the wider team up to speed on the approach.

What you will do:

• Design and build agents that produce production-grade .NET code.
• Implement a spec-driven development workflow (spec, plan, tasks, implement), using Spec Kit.
• Build review and approval gates so developers can verify and correct agent output before it is merged.
• Integrate tools and data sources into the agents via MCP (Model Context Protocol).
• Set up evaluation, guardrails and tests to catch incorrect output early.
• Work alongside engineering team’s and upskill them on agentic patterns and the spec-driven approach.
• Proven track record building and shipping AI agents in production, including tool calling, orchestration and multi-step workflows. Prototype-only experience will not be enough.
• Strong .NET and C# background (.NET 8/9, ASP.NET Core).
• Hands-on with a .NET-native agent framework, such as Microsoft Agent Framework or Semantic Kernel.
• Experience building agents whose output is code, with a clear focus on validating and verifying correctness.
• Familiarity with spec-driven development, ideally Spec Kit.
• Experience integrating tools via MCP.
• Designing human-in-the-loop review and approval gates within agent workflows.