Senior Agent Platform Engineer

Proxima Fusion GmbH; München; On-site; EUR 120,000 - 180,000; Full time

Job summary

Proxima Fusion in Munich is seeking a Senior Platform Engineer to own the AI agent platform: design, delivery, and operation of durable sessions, sandboxed execution, and tool integration. You will shape architecture, evaluate models and protocols, and drive platform improvements for reliability and scale.

You will work with Kubernetes on GCP, ensure security by design, and collaborate with expert users to align the roadmap with product needs and scientific workflows.

Qualifications

• 5+ years of software engineering experience with Python and distributed backend systems.
• Experience architecting, building, and operating production-grade agentic or LLM systems.
• Hands-on knowledge of MCP, agent SDKs and CLIs, multi-agent orchestration patterns, sandboxed code execution.

Responsibilities

• Own the design, delivery, and operation of our agent platform, including runtime, sessions, sandboxed environments, and tool integration.
• Turn evolving agent ecosystems into stable platform building blocks, deciding supported primitives vs experiments.
• Co-Design the integration layer connecting agents to internal/external systems and scientific computing stacks.
• Ensure autonomy safety with permission flows, human-in-the-loop escalation, and governance.
• Build evaluation and observability for non-deterministic systems with tracing, evals, and cost visibility.
• Operate the platform on Google Cloud with reliability, failure handling, and observability.
• Collaborate with demanding technical users to feed feedback into the roadmap.

Skills

Python

Distributed systems

LLM/agent tech

Kubernetes

GCP

Security by design

Terraform

CI/CD

Tools

MCP

Agent SDKs

CLIs

Sandboxed execution

Job description

WHO WE ARE

Proxima Fusion is Europe’s fastest-growing fusion company and the continent’s best-funded fusion player, as well as the first spin-out from the Max Planck Institute for Plasma Physics (IPP). Backed by over €650M and powered by a growing team across Munich, Zurich, and Oxford, we are developing the hardware and infrastructure needed to deliver the world’s first commercial stellarator fusion power plant.

Our concept advances the most mature fusion technology out there, the Wendelstein 7-X stellarator, through two next-generation machines: Alpha and Stellaris. Our work combines stellarator optimization, advanced computation, machine learning, and high-temperature superconducting magnets to unlock higher-performance designs that were previously out of reach.

Turning these designs into a functioning fusion power plant requires excellence and ownership across every discipline, from physics and engineering to software, manufacturing, law, and business functions.

WHY JOIN PROXIMA FUSION

• You will get to work on some of the most complex tech challenges to bring abundant, safe, clean energy to the world.
• You’ll get to join and learn from an exceptional selection of accomplished and driven individuals.
• Do your life’s best work and enjoy the journey.
• Get to show that big things are possible in Europe when you assemble the best talent.

YOUR IMPACT

• Technical owner of Proxima’s AI agent platform, turning autonomous agents into reliable everyday colleagues for physicists and engineers.
• Own the platform architecture, technical delivery, and day-to-day operation.
• Scale the platform from an early product into reliable, governed infrastructure used across the company.
• Enable agents to work across knowledge bases, write code, run simulations, and support engineering workflows.
• Work within the Enterprise AI Team Lead’s overall vision while owning how that vision is technically implemented.
• Use strong technical judgment to influence and shape the platform roadmap.
• Identify and propose new platform features based on hands-on experience and feedback from internal users.
• Build a platform that engineers and scientists can trust for real, production-level work.

WHAT YOU WILL DO

• Own the design, delivery, and operation of our agent platform: the runtime and its primitives: durable sessions, sandboxed execution environments, long-running task execution, memory, and tool integration
• Turn a rapidly evolving agent ecosystem into stable platform building blocks: evaluate harnesses, models, and protocols as they emerge, and decide what becomes a supported primitive versus a passing experiment
• Co-Design the integration layer that connects agents to internal and external systems, from enterprise tools to our scientific computing stack, and the standards for how tools, skills, and context are exposed to agents
• Make autonomy safe and governable: permission and approval flows with human-in-the-loop escalation, capability boundaries, audit logging, cost and token controls, and hardening against prompt injection and tool abuse
• Build the evaluation and observability layer for non-deterministic systems: session tracing, quality evals, and cost/latency visibility, so we know agents work before our users have to find out
• Operate what you build on Google Cloud with production discipline: reliability, failure handling, and observability
• Work directly with demanding technical users and feed their feedback and your technical judgment into the platform roadmap you shape together with the team lead

WHO YOU ARE

*This role sits at "L3" of our framework, please inquire during the recruitment process for further information.

MUST HAVE

• You have 5+ years of software engineering experience, with real depth in Python and distributed backend systems
• You have architected, built, and operated production-grade agentic or LLM systems well beyond the prototype phase
• You know the current agent ecosystem hands-on: MCP, agent SDKs and CLIs, multi-agent orchestration patterns, sandboxed code execution and have formed opinions on where the abstractions should sit
• You have run production workloads on Kubernetes and a major cloud (ideally GCP), and know what it takes to keep stateful, long-running services alive
• You treat evaluation and observability as platform features, not afterthoughts
• You take security seriously as a design constraint
• You think in platforms and internal products
• You are a low-ego, high-clarity communicator who can work directly with expert users and build consensus across teams
• You have experience with infrastructure as code (Terraform) and CI/CD

NICE TO HAVE

• Experience with model gateways and routing
• Exposure to scientific or high-performance computing: batch schedulers, HPC clusters, or simulation-heavy environments
• Open-source contributions to AI/agent tooling
• A track record of technical mentorship

INTERVIEW PROCESS

• Recruiter Interview (30-60 min)
• Technical Screening (30 min)
• Technical Panel (3x60 min)
• CEO call (30min)

At Proxima Fusion, our mission is bold: making limitless clean energy a reality. To get there, we need a high-performing, diverse team that brings different perspectives, challenges assumptions, and builds together with purpose. We know that diversity of thought and experience leads to better ideas, stronger execution, and a more resilient team. We don’t look at how you identify, what you look like, who you choose to worship or what ethnicity you are. We care about what you can bring to the table.