Build old and new apps with coding agents
Terence Tao describes using modern coding agents to create or revive apps, based on the post title.
Done with a custom-built or unnamed agent
- What they did
- Tao asked an AI agent to port about two dozen of his 1999 Java applets to JavaScript. The agent worked out the code from the source and its HTML page. For complex apps he had it build the math engine and test it before the GUI. He then vibe-coded two new apps in conversation: a special relativity spacetime diagram tool and a Gilbreath conjecture visualization.
- How it went
- The port took hours and all the applets work again. He found one minor drag bug, and the agent found two bugs in the original code. Each new app took a few hours. He calls the relativity app alpha.
- Worth knowing
- Tao says his programming and domain expertise were essential for steering the agent and diagnosing problems. He considers the low-stakes visual aids an acceptable place to risk bugs.
Try it yourself with Claude Code
Build a small app that [describe what it does] in a new folder, or revive my old project at [path] that no longer runs. Start by writing a short plan, then work in small steps, running it and fixing errors as you go. Finish when I can launch it with a single command, and give me a short summary of what you changed. Ask before deleting any existing files.
Discussion on HN · Jul 12, 2026
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