On June 12 (early morning Beijing time), the OpenAI Developers official account announced that Codex has launched a Developer Mode in both the Chrome browser and Codex's in-app browser.
The key of this update is not flash, but that Codex can now debug the browser directly using the Chrome DevTools Protocol (CDP) — meaning Codex, for the first time, can "see the real state of a page" rather than just reading source code, looking at screenshots, and letting an LLM guess.
What it can actually do
According to OpenAI's official description, Codex can do four things inside Chrome and the built-in browser:
- Capture and analyze JavaScript performance profiles
- Pull console output
- Inspect network traffic
- Inspect the current page state (including DOM, Storage, etc.)
- June 11, 00:00: OpenAI announced it will acquire Ona, specifically to build out "secure, persistent cloud environments" supporting "long-running AI agents"
- June 11, 23:58 (Beijing time): Codex rolled out rate-limit reset banking — one free "banked reset" for Go/Plus/Pro/Business users
- June 12, 00:11: Browser Developer Mode
- June 10: Qwen gained committed access to OpenAI models and Codex via Oracle Cloud
- For frontend developers: the experience of "AI watching DevTools and debugging with you" is about to become routine. CDP is the standard interface for plugging AI into the browser workflow.
- For AI engineers: protocols like CDP that let AI "see real-world state" represent a broader paradigm — the same logic could extend to mobile ADB, embedded devices, and industrial control protocols. This Codex update is a miniature blueprint.
- For those watching agent governance: a browser that can read console output, capture network traffic, and inspect the DOM raises the question of where permission boundaries lie. OpenAI didn't discuss security details this time, but the browser-side permission model will be a question that must be answered next.
- Official announcement: https://x.com/OpenAIDevs/status/2065226355495895521
- Rate-limit reset banking: https://x.com/OpenAI/status/2065225362544726371
- Ona acquisition: https://openai.com/index/openai-to-acquire-ona
In short: previously, if you asked Codex to fix a "sluggish page," it could only modify code based on experience and let you refresh to check the result. Now it can behave like a real frontend engineer — opening DevTools to read flame graphs, see which requests are slow, and read which JS code is throwing errors.
Why CDP
CDP is the set of debugging interfaces that Chrome/Edge expose to external programs; the browser's own DevTools is built on top of it. By connecting to CDP, Codex is put on the same toolchain as human developers. This both expands what Codex can do by a whole dimension and implies deeper integration with IDEs and local tooling.
Context: Codex is becoming OpenAI's all-in-one development platform
Viewed within OpenAI's moves over the past month:
Codex is no longer just a "code completion box" or an agent in a terminal — browser, terminal, long-horizon agents, cloud environments: OpenAI is packing in capabilities on a weekly cadence.