Michael Truell (마이클 트루엘), CEO of AI coding tool Cursor developer Anysphere, recently drew attention after promoting that he built a web browser called FastRender based on GPT-5.2 and ran it without interruption for a week.

FastRender consists of more than 3 million lines of code and thousands of files, he said. He said it implements everything in-house, from HTML parsing to CSS, layout, text processing and its own JavaScript virtual machine (JS VM).

But the response from developers has been cool. According to a recent report by The Register, Jason Gorman (제이슨 고먼) of British software consultancy Codemanship said it effectively proved an AI agent can write a large project, but the output quality is terrible. The Register said an 88 percent task failure rate was recorded in FastRender's GitHub repository, raising questions about code stability.

Some developers said they succeeded in compiling it by modifying build instructions or fixing bugs, but overall many responses said it works but is hard to call it a browser engine, The Register said.

Software engineer Oliver Medhurst (올리버 메드허스트), who has experience developing web browsers, said it was only impressive in that it can generate large-scale code, and pointed out that FastRender is not a genuinely competitive browser. He added, "Servo by Mozilla or Ladybird achieve more with under 1 million lines of code."