OpenAI Codex Gets a GPT-5 Boost: New GPT-5 Codex Could Change How You Code Forever

August 27, 2025 — OpenAI’s developer account announced a substantial Codex upgrade that turns the company’s coding agent into a more native part of everyday development workflows. The release introduces a new IDE extension, automatic code reviews in GitHub, an upgraded CLI, and the ability to move tasks between Codex’s cloud sandbox and a developer’s local environment without losing state.

What’s new

• IDE extension (VS Code, Cursor, and other VS Code forks): Work side-by-side with Codex, share files/snippets/diffs, and preview/edit local changes directly in the editor.
  

• Seamless cloud ↔ local hand-off: Start a task locally, delegate longer runs to Codex in the cloud, then pull results back—state stays in sync via your ChatGPT account.
  

• GitHub code reviews: Codex can review new pull requests automatically or on mention, proposing fixes and suggestions. 

• Revamped Codex CLI: A refreshed interface with new commands and reliability improvements, designed to pair with the IDE experience.
  

• Sign-in with ChatGPT (no API key required): Use Codex through your existing ChatGPT plan across IDE and CLI.
  

Codex CLI

We’ve rebuilt the Codex CLI to harness GPT-5’s agentic coding capabilities so it's more reliable and capable.

We’ve redesigned the terminal UI and also added image inputs, message queuing, simplified approval modes, to-do lists, web search, and more. pic.twitter.com/Hcc4nqRXkn

— OpenAI Developers (@OpenAIDevs) August 27, 2025

Availability and models

OpenAI recommends GPT-5 as the default model for Codex, and the agent is included in ChatGPT Plus, Pro, Team, Edu, and Enterprise plans. That means most paid ChatGPT users can try the update immediately without extra setup. 

Why it matters

The update pushes Codex from a “nice-to-have assistant” toward an end-to-end coding agent that lives where developers already work—editor, terminal, GitHub, and the cloud—while keeping context portable. Consolidating identity and state through a ChatGPT account removes friction (keys, tokens, hand-offs), and the GitHub review hooks aim to turn Codex into a continuous reviewer rather than a one-off chat helper. 

How to get started

• IDE: Install the OpenAI Codex extension from the VS Code Marketplace (also works with Cursor and forks), then sign in with your ChatGPT account. 

• CLI: Install @openai/codex globally (e.g., npm install -g @openai/codex) and sign in with ChatGPT; the CLI is open-source on GitHub for those who want to inspect or contribute.
  

• Docs & guides: OpenAI has a central Codex hub covering IDE, CLI, and cloud usage. 

The announcement

OpenAI’s developer team summarized the release as: “A new IDE extension; easily move tasks between the cloud and your local environment; code reviews in GitHub; revamped Codex CLI—powered by GPT-5 and available through your ChatGPT plan.”

Codex’s “one agent, everywhere you code” framing aligns with OpenAI’s May preview of Codex as a cloud software-engineering agent and continues that trajectory into daily tools developers already use. If adoption sticks, expect more workflows (test generation, migrations, refactors) to start in the editor, escalate to cloud execution, and land back in Git within a single loop.