Principal Software Engineer

OB Collective develops independent verification technology for organisations operating in government, regulated and high-assurance environments. Our work is concerned with establishing reliable evidence about information and automated actions before organisations rely on them.

We’re building a senior technical team for a six-twelve month engagement on a UK public-sector R&D programme focused on the cybersecurity and operational assurance of AI agents. We’re looking for a Principal Technical Lead / Architect to take overall technical responsibility for the software capability and lead its engineering development.

As AI agents gain access to organisational data, credentials, tools, APIs and enterprise systems, organisations need stronger ways to understand the conditions surrounding consequential actions and the risk those actions create. The programme will extend an existing software capability into agentic environments, integrate it with existing security and control systems, and evaluate its behaviour under realistic operational, failure and adversarial conditions.

There is an existing technical capability and a defined research direction. The challenge is to extend and validate that capability while maintaining clear security boundaries, engineering correctness, reproducibility and performance.

You will take day-to-day technical ownership of the software and lead a small team of experienced engineers. Your responsibilities will span architecture, system design, code-level investigation, engineering decisions, technical reviews and release readiness.

This is a hands-on technical leadership role. We need someone who can understand an unfamiliar codebase, make sound architectural decisions, investigate difficult implementation problems and remain directly involved in engineering delivery.

Strong Rust experience is highly desirable, but candidates with substantial systems engineering experience in Go, C++, Java or comparable languages will also be considered.

The role is UK-based, outside IR35, full-time and primarily remote, with occasional travel for workshops and technical activity.

What you’ll do

• Take technical ownership of the existing software capability and its evolution.
• Establish and maintain the programme’s technical architecture, design principles and engineering standards.
• Understand the existing codebase, build process, operating assumptions, interfaces and technical debt.
• Define clear system and trust boundaries across agent platforms, enterprise services and security controls.
• Lead the architecture for independently observable evidence surrounding selected automated actions.
• Establish how incomplete, contradictory or unavailable evidence should be represented without overstating what the system can verify.
• Own non-functional requirements covering security, reliability, performance, portability and resilience.
• Lead interface and integration design across different platforms, tools and enterprise systems.
• Review code and designs, investigate difficult technical problems and provide hands-on engineering support.
• Maintain architectural coherence across parallel research and development workstreams.
• Lead technical investigation of failure modes, scale constraints and resilience issues.
• Support security reviews, adversarial evaluation, remediation and technical release readiness.

What we’re looking for

• Deep hands-on software engineering experience, including significant architecture responsibility.
• Experience designing and building complex backend, distributed, infrastructure or security-sensitive systems.
• Evidence of personally owning important architecture decisions and remaining involved through implementation.
• Strong practical ability in Rust or another relevant systems or backend language.
• Ability to understand, debug and modify unfamiliar production codebases.
• Strong understanding of trust boundaries, failure modes, system state, interfaces and distributed-system behaviour.
• Experience designing reliable APIs and integrations across system boundaries.
• Sound engineering judgement around observability, incomplete information and security assumptions.
• Experience leading senior engineers while remaining technically hands-on.
• Strong testing, code review and debugging discipline.

Preferred experience

• Production Rust development.
• Security infrastructure or high-assurance backend software.
• Cryptographic integrity mechanisms, including hashing, digital signatures and key management.
• Provenance, event processing, secure logging or tamper-evident systems.
• IAM, delegated authorisation or policy systems.
• AI-agent frameworks, tool orchestration or agent security.
• Self-hosted, hybrid, restricted-network or disconnected environments.
• Government, defence, financial services or critical infrastructure.