Senior AI Agent Engineer - Lead, Durable Automation

EY; St. Louis (MO); Hybrid; USD 173,000 - 359,000; Full time

Benefits offered by this job

Medical and dental coverage

Pension and 401(k) plans

Generous time off

Job summary

EY Challenger is building the next generation of AI-enabled services. We seek senior engineers to design and ship durable agent systems, with a strong focus on production reliability, security, and governance.

You will work across enterprise integrations and complex workflows to deliver value in real-world settings. This role emphasizes long-running agents, multi‑team collaboration, and measurable outcomes, with up to 50% travel and hybrid office options across the US.

Qualifications

• Bachelor’s degree in a relevant field and 9+ years of experience in software or applied machine‑learning engineering.
• Hands-on evidence shipping large‑language‑model applications, agents, or complex model‑driven workflows in production.
• Strong production‑service and integration capabilities in Python/TypeScript or equivalent languages.
• Experience with model APIs, structured outputs, retrieval, and evaluation of variable behavior.
• Practical command of asynchronous work, state, concurrency, idempotency, retries, and failure recovery.

Responsibilities

• Choose the right execution model and design agent architectures for deterministic steps or single-agent loops when beneficial.
• Build dependable tools with clear contracts, validated outcomes, and safe error handling for recovery.
• Engineer agent behavior including planning, routing, delegation, stopping, and retry across workflows.
• Create durable context by combining instructions, user state, retrieval, and memory while preserving relevance.
• Bound agent authority with scoped identities, credentials, and emergency containment.
• Evaluate complete trajectories with tests that measure verified task success and safe use of tools.
• Operate long-running execution using durable state, versioned releases, and graceful degradation.
• Make behavior observable with end-to-end tracing and replay for diagnostics and improvements.
• Protect user control with clear intervention points to inspect, interrupt, and resume work.
• Build shared capability by collaborating across teams and publishing reusable agent patterns.

Skills

Production engineering

Agent architecture

AI application depth

Evaluation discipline

Security and operability

Product judgment

Education

Bachelor’s Degree

9-12+ years experience

Production systems ownership

Tools

Python

TypeScript

Job description

EY Challenger is building the next generation of AI-enabled services. We seek senior engineers to design and ship durable agent systems, with a strong focus on production reliability, security, and governance.

You will work across enterprise integrations and complex workflows to deliver value in real-world settings. This role emphasizes long-running agents, multi‑team collaboration, and measurable outcomes, with up to 50% travel and hybrid office options across the US.