The provided sources offer an extensive overview of OpenAI's recent release, GPT-5-Codex, a specialized agentic model designed for software engineering tasks. The articles and discussions highlight the model's key differentiating feature, "variable grit," which allows it to dynamically adjust its reasoning time, tackling simple tasks quickly while persistently working on complex refactoring or debugging for up to seven hours. Developers generally report that Codex excels at autonomous development workflows and thorough code reviews, often surpassing competitors like Claude Code in complex, long-running tasks, though some users note instances of erratic behavior requiring human guidance. The sources also detail the model's multiple interfaces, including a Command Line Interface (CLI), IDE extensions, and a Cloud version, and feature commentary from OpenAI co-founder Greg Brockman, who emphasizes the model's role as a reliable engineering partner and a major step toward realizing an "agentic software engineer."