OpenAI

AI Systems Engineer Codex Agents

In short

This role builds agent harnesses and execution loops for AI agents that use tools and execute code, covering sandboxing, orchestration, evaluation, observability, and reliability/latency/cost/safety improvements for long-horizon task execution. The company is OpenAI, hiring for a senior-level production systems role requiring Rust, Python, distributed systems, and LLM/inference experience. It demands strong debugging skills for ambiguous production failures and building shared infrastructure primitives for the agent stack.

About the Role
You will build agent harnesses and execution loops that interpret model outputs, use tools, execute code, and safely complete long-horizon tasks. You will develop sandboxing, orchestration, evaluation, experimentation, observability, and diagnostic systems while improving reliability, latency, cost, and safety.
Requirements
•Experience building or operating production distributed systems, infrastructure, developer tooling, sandboxing, virtualization, cloud platforms, or ML systems
•Experience with Rust, Python, APIs, agent orchestration, evaluations, logs, traces, inference behavior, and runtime constraints
•Experience with LLM applications, coding agents, evaluations, model deployment, inference, compiler or runtime performance, or developer platforms
•Knowledge of reliability, safety, performance, debuggability, and system abstractions
•Ability to debug ambiguous production failures and deliver durable fixes
Responsibilities
•Design and build agent harnesses and execution loops
•Build sandboxing, isolation, orchestration, state, and workflow infrastructure
•Develop evaluation, experimentation, and debugging systems
•Run ablations across prompts, interfaces, context, tools, and harness behavior
•Improve observability, profiling, and diagnostics across the agent stack
•Build shared primitives for faster, safer, and more reliable agents
Benefits
•Medical, dental, and vision insurance for employees and their families
•Employer contributions to Health Savings Accounts
•Health FSA, Dependent Care FSA, and commuter expense accounts
•401(k) plan with employer match
•Paid parental, medical, and caregiver leave
•Flexible paid time off for exempt employees
•Paid company holidays and office closures
•Paid sick or safe time
•Mental health and wellness support
•Employer-paid basic life and disability coverage
•Daily office meals and eligible meal delivery credits
•Relocation support for eligible employees
•Charitable donation matching
•Wellness stipends
•Equity
•Performance-related bonuses for eligible employees

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