Willison has Claude Opus 5.5 evaluate webframe as sandbox and scraper
On 26 October 2026 Simon Willison wrote about webframe, which he calls a neat little project from Jeff Lindsay. Its pitch is that it lets you "run a web page like a program". You point it at a URL or a file, and it executes the page in a hidden headless web view. Anything the page writes with console.log() goes to standard output, and any exceptions go to standard error.
Willison describes the implementation briefly. It is written in Go on top of the glaze library, which gives access to a system browser: WKWebView on macOS, WebKitGTK on Linux and WebView2 on Windows. Because it uses the browser already on the machine, webframe does not need to bundle its own browser engine.
Willison says it reminds him of his own shot-scraper javascript tool, though in a much smaller package that does not depend on Playwright.
He then had Claude Opus 5.5 put webframe through its paces and prepare a research report. The post shows the prompt he used. It asks the model to explore the webframe repository on GitHub (tractordev/webframe), try running it, build a few exploratory prototypes, and then evaluate it in two roles: as a potential sandboxing tool, and as a tool for scraping web pages. For the scraping part, the model was told to follow the same patterns encouraged by the "shot-scraper JavaScript" command, pointing it at the simonw/shot-scraper repository's docs directory.
The post is a short note. It carries the description of the tool and the prompt, and does not give the findings or verdict of the report.
Key facts
- webframe, a project from Jeff Lindsay, runs a URL or file in a hidden headless web view and sends console.log() to standard output and exceptions to standard error.
- It is written in Go on the glaze library, which uses the system browser (WKWebView on macOS, WebKitGTK on Linux, WebView2 on Windows), so no browser engine is bundled.
- Simon Willison compares it to his shot-scraper javascript tool, in a much smaller package that does not depend on Playwright.
- Willison had Claude Opus 5.5 explore the repository, build exploratory prototypes and evaluate webframe as a sandboxing tool and as a web scraper.
- The post publishes the prompt but not the report's findings.
Why it matters
Running a page's JavaScript and capturing its console output is a common need for scraping and for running untrusted code. webframe does it with a small Go program that borrows the browser already installed on the system instead of shipping its own engine. Willison points to the contrast with his shot-scraper javascript tool, which relies on Playwright: webframe covers similar ground in a much smaller package without that dependency. The post is a pointer to a niche tool, not an announcement of an industry shift.
Who it affects
Developers who script web pages from the command line, especially people who scrape pages with JavaScript, as shot-scraper users do. It also touches anyone weighing options for sandboxing code in a web view. The tool targets macOS, Linux and Windows through each platform's system web view.
How to use it
Per the post, you point webframe at a URL or a file. It runs the page in a hidden headless web view, prints console.log() output to standard output and sends exceptions to standard error, so a page behaves like a command-line program. The code is at github.com/tractordev/webframe. Willison's prompt is a reusable template for getting a coding model to evaluate a tool: explore the repository, run it, build a few exploratory prototypes, then judge it for specific uses and point to reference docs for the patterns to follow.
How solid is it
This is a short blog note from Willison, who describes webframe and shares his prompt. The description of how webframe works comes from him. The post does not report the results of the Claude Opus 5.5 research report. It also gives no assessment of webframe as a sandbox, and no performance numbers, version number, license or release date.
Risks and caveats
The sandboxing question is open in this post: it states what was asked of the model, not what was found, so it should not be read as a security endorsement. Nothing in the post says whether Willison ran the tool himself or only had the model run it. The tool relies on whichever system browser component each platform provides.
“run a web page like a program”
— webframe's description of itself, as quoted by Simon Willison