Codex

Overview

Codex is OpenAI’s AI coding agent, announced at DevDay 2024 and reaching General Availability (GA) in October 2025. It is available through ChatGPT, providing code generation, editing, and task execution capabilities integrated with Slack, GitHub, and other platforms.

Key Features

• Slack Integration: Assign tasks or ask questions directly in team channels
• Codex SDK: Embed Codex-powered agents into custom workflows and applications
• Admin Tools: Environment control, monitoring, and analytics for enterprise
• Multi-platform: Available in editor, terminal, and cloud (all connected via ChatGPT)

Growth Metrics

• 10x+ growth in daily active usage since August 2025
• 40 trillion tokens processed in first 3 weeks after GPT-5-Codex launch
• 70% increase in weekly merged PRs for OpenAI internal engineers
• Adopted by companies like Duolingo, Vanta, Cisco, Rakuten

Architecture

Codex is powered by GPT-5-Codex model, optimized specifically for coding tasks. It can:

• Read and understand entire codebases
• Generate code across multiple languages
• Execute terminal commands
• Create and manage GitHub issues and PRs
• Review code automatically

Applications Beyond Coding

• Video Editing: Codex combined with HyperFrames is automating professional video editing workflows, showing crossover from coding agent to creative tool. See ../sources/2026-05-06-Codex + HyperFrames 正在吃掉剪辑行业.

2026-08-10 KnowFlow：从四个 Codex Skills 迁移到 Obsidian 原生插件

KnowFlow 的前身是作者在 Codex 上拆出的四个 Skills（clipping-update / daily-learning / study-outline / study-quiz），实现”剪藏 → 清洗 → 摘要 → 知识图谱 → 测验”的 AI 知识工作流；但每处理一篇文章都要离开 Obsidian 去 Codex 里重新描述文件，“学习变成一串需要记住的命令”。作者随后把整套流程迁移为 Obsidian 原生插件（侧边栏自动携带当前笔记上下文），工具切换摩擦随之消失。这是”外部 Agent Skills 工作流 → 宿主环境插件化”演进路径的具体实例：能力不变，载体向数据所在地移动——工具切换成本（而非功能缺失）才是知识流程中断的主因。见 Source: KnowFlow。

Comparison with Claude Code

Aspect	Codex	Claude Code
Platform	ChatGPT-integrated	Standalone CLI
Integration	Slack, GitHub	GitHub, MCP
Use Case	Team collaboration	Individual/enterprise
Pricing	API-based	Subscription

Related Entities

• OpenAI: Parent company
• Claude Code: Primary competitor
• Cursor: Competitor (IDE-based)

Source

OpenAI DevDay 2025

See Also

• OpenAI (parent company)
• Claude Code
• Cursor