How to use Codex to build a browser from scratch
An author and one Codex agent built a roughly 20,000-line browser with system libraries, basic rendering and navigation, cross-platform support, CI builds and automatic releases.
news.ycombinator.com
Suggested prompt
Suggested prompt written by Agents In Use, not the source author. Replace bracketed inputs and review tool permissions first.
Help build a browser from scratch for [target platforms], using only [commonly available system libraries] and no third-party crates. Include basic rendering, link navigation, scrolling, scaling, headless screenshots and CI releases. Document compatibility limits.
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See placements →Evidence at a glance
Sourced account- Source poster / publisher
- embedding-shape
- Original account
- Read the source ↗
- Published
- Source link checked
- Reported result
- The author reports a roughly 20,000-line cross-platform browser that handles basic sites mostly well, includes navigation and screenshot features, and has automated builds and releases.
- Human involvement
- The author set project constraints and reported rendering limitations; specific review and test procedures are not described.
A linked account supports attribution. It does not mean we independently reproduced its result.
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How the agent did it
- Constrain the browser project to system libraries without third-party crates.
- Build the browser with a single Codex agent.
- Include headless operation, screenshots, scaling and navigation controls.
After criticizing an earlier browser experiment, the author tried building a browser from scratch with a single Codex agent. They constrained the project to commonly available system libraries and excluded third-party crates. The result, they report, was about 20,000 lines of code, including support for X11, macOS and Windows.
The browser includes headless operation and screenshots, plus scaling, link clicking and scrolling. The author says it renders basic websites such as Hacker News mostly well, while most other sites fare poorly. That limitation is part of the reported result: the post does not establish broad compatibility with modern websites.
The project also includes CI builds and automatic releases. The author shared a repository, directed readers to its releases for downloads and said it should run out of the box on most modern operating systems. Their comparison with a larger multi-agent browser effort is an author claim, without comparative testing supplied in this source.
Who it's for: Developers exploring a constrained browser implementation and willing to work with limited rendering compatibility.
Prompt
Suggested prompt (written by Agents In Use, not the author's)
Source: Hacker News · embedding-shape
Frequently asked questions
What dependencies were allowed?
The author allowed commonly available system libraries and explicitly excluded third-party crates.
How well does the browser render websites?
The author says basic websites such as Hacker News render mostly fine, while most other sites do not.
What platform and release support was included?
The reported code includes X11, macOS and Windows support, plus CI builds and automatic releases.
More details
Remaining steps
- Add CI builds and automatic releases, then share the repository.
About this account
The author worked with one Codex agent under explicit dependency constraints; the source does not detail unattended execution.
Platform: Hacker News. Attribution: https://news.ycombinator.com/item?id=46782154. Prompt: Suggested (written by Agents In Use, not the author's). Sourced by the Agents In Use pipeline.
Credit: embedding-shape on Hacker News
Source published
Added to Agents In Use
Source checked
Tools and topics
Codex · System libraries · GitHub · CI
Web browser · Cross-platform · Systems programming
Editorial completeness: 100/100. Measures documented fields, not agent performance or verified outcomes.