Applied AI Engineer: Codex Core Agent for Real-World Tasks

OpenAI, Inc.; City Of London; On-site; GBP 90,000 - 180,000; Full time

Job summary

OpenAI is seeking applied AI engineers to advance Codex agents from demos to dependable tools. You will improve agent performance on real software tasks, close the gap between research and real-world usefulness, and drive measurable gains in solve rate and user value.

You’ll work with research, infra, and product to ensure agents are powerful, steerable, and reliable in practice, turning research into practical, scalable solutions for users.

Qualifications

• Experience building or shipping ML/LLM-powered products.
• Strong Python and comfortable with modern ML tooling.
• Experience with model evaluation, fine-tuning, or prompt design.

Responsibilities

• Design and iterate on agent behaviors across real-world coding tasks and long-horizon workflows.
• Develop and run evals to measure agent performance, regressions, failure modes, and edge cases.
• Improve performance through prompting, tool-use strategies, context construction, and model-facing experimentation.
• Analyze failures in production and systematically improve robustness and reliability.
• Build feedback loops and data systems that get better real-task data into evaluation and research.
• Work with product teams to shape user-facing agent experiences and interfaces the agent depends on.
• Help define what “good” looks like for agents completing complex tasks end-to-end.

Skills

Python

ML tooling

LLM products

Model evaluation

Prompt design

Job description

OpenAI is seeking applied AI engineers to advance Codex agents from demos to dependable tools. You will improve agent performance on real software tasks, close the gap between research and real-world usefulness, and drive measurable gains in solve rate and user value.

You’ll work with research, infra, and product to ensure agents are powerful, steerable, and reliable in practice, turning research into practical, scalable solutions for users.