RefolkCandidates
JobsBuild my resume

AI Systems Engineer, Codex Agents

OpenAI · San Francisco

$230k - $385k/yrMid levelEngineeringApplied AICodex - EngineeringPosted 2 months ago
Apply with a tailored resumeView the original posting

About this role

AI Systems Engineer - Codex Core Agents About The Team The Codex Core Agents team builds the agent harness that turns model capability into real-world action. We own the systems around the model: prompting and interpreting model outputs, executing actions safely in real environments, and feeding production experience back into better models and better agent behavior. This team sits close to research and works across the stack: harness, model interaction, inference, sandboxed execution, orchestration, evals, production reliability, and the performance envelope around tokens, latency, cost, capacity, and quality. The harness is open source and increasingly part of how models are trained and evaluated, making this one of the highest-leverage layers in Codex. About The Role We’re looking for engineers to build the AI systems that make Codex agents dependable in production. The ideal candidate is an agent-systems builder: hands-on across low-level systems and ML workflows, able to debug Codex behavior end to end across the harness, model behavior, inference/runtime stack, GPU fleet, and product surface. You’ll work with research, infrastructure, and product to design agent harness capabilities, run experiments and ablations across the model + system prompt + harness stack, build frameworks for assessing production agent performance, and turn messy failures into durable improvements. What You’ll Do - Design and build the core agent harness and execution loop that lets Codex agents interpret model outputs, use tools, execute code, and complete long-horizon tasks safely. - Build sandboxing, isolation, orchestration, state, and workflow infrastructure for agents operating in real development environments. - Develop evaluation, experimentation, and debugging systems that distinguish harness issues, model behavior, inference/runtime issues, and product failures. - Run ablations across prompts, model-facing interfaces, context construction, tool-use strategies, and harness beha

Excerpt from the posting OpenAI published. Read the full description on their site before applying.

Skills this posting mentions

ResearchArtificial IntelligenceInfrastructure

About OpenAI

OpenAI is an AI research and deployment company dedicated to ensuring that general-purpose artificial intelligence benefits all of humanity. AI is an extremely powerful tool that must be created with safety and human needs at its core. OpenAI is dedicated to putting that alignment of interests first - ahead of profit. To achieve our mission, we must encompass and value the many different perspectives, voices, and experiences that form the full spectrum of humanity. Our investment in diversity, equity, and inclusion is ongoing, executed through a wide range of initiatives, and championed and supported by leadership. At OpenAI, we believe artificial intelligence has the potential to help people solve immense global challenges, and we want the upside of AI to be widely shared. Join us in shaping the future of technology.

All 755 openings at OpenAI

Apply to this role, tailored

Queue AI Systems Engineer, Codex Agents at OpenAI and I will read the posting, rewrite your resume against it, draft the cover letter, and score the fit before you send anything.

Applications finish as drafts. Nothing is sent until you read it and press send. New accounts start with 500 free credits.

Tailor my applicationHow it works

More roles at OpenAI

See all

Similar roles elsewhere

See more

Listed from the job board OpenAI publishes. Refolk is not the employer and does not handle their hiring. Applications go to OpenAI directly.