Senior AI Agent Runtime Engineer

Unusual; New York (NY); On-site; USD 180,000 - 240,000; Full time

Job summary

Helios is hiring a Staff/Senior Software Engineer, Agent Engineering, in New York City. This on-site, full-time role focuses on advancing the agent runtime for Proxi, enabling long-running, multi-agent workflows with robust tool and action infrastructure.

You will work with senior leadership and a founding team to ensure autonomous yet controlled agent behavior, grounded in trustworthy evidence and secure operations, across government-relevant contexts.

Qualifications

• Senior engineer who has shipped production LLM or agent systems beyond the prototype stage.
• Ability to diagnose nondeterministic failures and enforce boundaries between model judgment and deterministic software.
• Experience deciding when a workflow requires autonomy, human approval, or conventional application logic.

Responsibilities

• Own Proxi’s agent runtime and strengthen foundations for new agent-driven products.
• Build systems that allow agents to own long-running work from assignment through completion.
• Create tool and action framework for agents to safely interact with internal/external services.
• Connect agents to Proxi’s retrieval and knowledge systems to ground reasoning to evidence.
• Improve evaluation and release discipline for agent behavior, traces, and simulations.

Skills

Agent systems

LLM integration

Production engineering

Multi-agent orchestration

Tools

Tool & action framework

Retrieval systems

Knowledge grounding

Job description

Helios is hiring a Staff/Senior Software Engineer, Agent Engineering, in New York City. This on-site, full-time role focuses on advancing the agent runtime for Proxi, enabling long-running, multi-agent workflows with robust tool and action infrastructure.

You will work with senior leadership and a founding team to ensure autonomous yet controlled agent behavior, grounded in trustworthy evidence and secure operations, across government-relevant contexts.