# Harness engineering: leveraging Codex in an agent-first world

DevFeed: [Harness engineering: leveraging Codex in an agent-first world](<https://devfeed.tech/articles/harness-engineering-leveraging-codex-in-an-agent-first-world-6446.md>)

Original publisher: [Read original article](<https://openai.com/index/harness-engineering>)

Published: 2026-02-11T09:00:00Z

Content type: article

Language: en

Sources: [OpenAI News](<https://devfeed.tech/sources/openai-news.md>)

Topics: [codex](<https://devfeed.tech/topics/codex.md>), [Software Engineering](<https://devfeed.tech/topics/software-engineering.md>), [Code](<https://devfeed.tech/topics/code.md>), [App](<https://devfeed.tech/topics/app.md>), [ci](<https://devfeed.tech/topics/ci.md>), [Command-line interface](<https://devfeed.tech/topics/cli.md>), [pull-requests](<https://devfeed.tech/topics/pull-requests.md>), [Tooling](<https://devfeed.tech/topics/tooling.md>), [configuration](<https://devfeed.tech/topics/configuration.md>), [observability](<https://devfeed.tech/topics/observability.md>), [cloud-infrastructure](<https://devfeed.tech/topics/cloud-infrastructure.md>)

Tags: [agent](<https://devfeed.tech/tags/agent.md>), [agents](<https://devfeed.tech/tags/agents.md>), [building](<https://devfeed.tech/tags/building.md>), [ci](<https://devfeed.tech/tags/ci.md>), [cli](<https://devfeed.tech/tags/cli.md>), [code](<https://devfeed.tech/tags/code.md>), [codex](<https://devfeed.tech/tags/codex.md>), [developer](<https://devfeed.tech/tags/developer.md>), [development](<https://devfeed.tech/tags/development.md>), [documentation](<https://devfeed.tech/tags/documentation.md>), [engineering](<https://devfeed.tech/tags/engineering.md>), [infrastructure](<https://devfeed.tech/tags/infrastructure.md>), [observability](<https://devfeed.tech/tags/observability.md>), [pull-requests](<https://devfeed.tech/tags/pull-requests.md>), [software](<https://devfeed.tech/tags/software.md>), [software-engineering](<https://devfeed.tech/tags/software-engineering.md>), [tooling](<https://devfeed.tech/tags/tooling.md>)

## AI overview

OpenAI describes a five-month experiment in which Codex agents generated and maintained an internal software product, including its code, tests, CI configuration, documentation, observability, and tooling. The team reports roughly one million lines of code, about 1,500 merged pull requests, and development in about one-tenth the estimated manual-coding time.

## Source excerpt

By Ryan Lopopolo, Member of the Technical Staff