OpenAI Codex CLI
4 source-verified cases.
- Automate defect remediation across C/C++ codebases with Codex CLIRecreated promptEvidence: Company case study
According to OpenAI's case study, Cisco's Codex CLI defect-repair workflow raised defect resolution throughput 10–15x, and Codex build optimization saved more than 1,500 engineering hours a month.
According to OpenAI:10–15x defect resolution throughput
OpenAI Codex CLI · Coding · Source date:
- Port an HTML5 parser from Python to JavaScript with Codex CLIEvidence: Screenshots or logs
Codex CLI (GPT-5.2) ran for hours largely unattended and produced about 9,000 lines of dependency-free JavaScript passing 9,200 html5lib tests, in about 4.5 hours start to finish.
Poster says:Passes 9,200 html5lib tests
OpenAI Codex CLI · Coding · Source date:
- Compare Claude Code, Codex and Gemini CLI on a 97k-message chat datasetRecreated promptEvidence: Described by poster
The poster gave the same 97k-message WeChat dataset to Claude Code, Codex and Gemini CLI as analysts and published results with an evaluation table.
Claude Code, OpenAI Codex CLI, Gemini CLI · Data · Source date:
- Upgrade a plugin to a new framework alpha with Codex CLIEvidence: Screenshots or logs
A one-line `codex exec` loop read the Datasette 1.0a20 upgrade docs, fixed the failing tests, and got the datasette-checkbox plugin passing again.
OpenAI Codex CLI · Coding · Source date: