Comment by simonw

The hardest problem in computer science in 2025 is showing an AI cynic an example of LLM usage that they find impressive.

How about this one? I had Claude Code run from my phone build a dependency-free JavaScript interpreter in Python, using MicroQuickJS as initial inspiration but later diverging from it on the road to passing its test suite: https://static.simonwillison.net/static/2025/claude-code-mic...

Here's the latest version of that project, which I released as an alpha because I haven't yet built anything real on top of it: https://github.com/simonw/micro-javascript

Again, I built this on my phone, while engaging with all sorts of other pleasant holiday activities.