Vol. 01 · Field notes on AI & dev tools5 entries so far
Hi, I'm Nilay.
I test AI & dev tools, then write down what actually happened.
I'm a developer. I try new models, frameworks and tools on real projects, and keep notes: what it cost, how fast it was, what broke and how I fixed it. This site is those notes, cleaned up.
start here: entry No.005
On my desk now
the first fixes for this notebook
Rules of this notebook
- 1.Every error reproduced first.
- 2.Exact versions, written down.
- 3.Real numbers, not adjectives.
- 4.Failures stay in the post.
- 5.Nobody pays for a verdict.
— N.K.
On the bench lately
AI models, Coding agents, LLM APIs, Next.js, Astro, Cloudflare, Vercel, Node.js, Android, Automation, Dev tools, Open-source.
Part 01 · coming soon
Tested
AI models and dev tools, run for real: speed, cost, what broke.
first entries are being written
Part 02 · 5 entries
Fixes
Exact error message, why it happens, the fix that worked, versions tested.
Open →
The log
Follow by RSS- No.005
Fix: “trying to use tailwindcss directly as a PostCSS plugin”
Tailwind CSS v4 moved its PostCSS plugin to a separate package. The two-line change to postcss.config.js, reproduced and verified.
> Error: It looks like you're trying to use `tailwindcss` directly as a PostCSS
FIXED1 min - No.004
Fix: “Cannot apply unknown utility class” in Tailwind CSS v4
Two causes trigger this Tailwind v4 error: an unmapped theme variable (border-border) or a CSS file missing @reference. Both reproduced and fixed.
> Error: Cannot apply unknown utility class `border-border`
FIXED1 min - No.003
Fix: npx tailwindcss init “could not determine executable to run”
Tailwind CSS v4 removed the init command, so npx has nothing to run. Two fixes, both reproduced: set up v4 without a config file, or pin v3.
> $ npx tailwindcss init
FIXED2 min - No.002
Fix: EADDRINUSE address already in use :::3000 on Windows
Your Node dev server won't start because the port is taken. Find the process holding it, stop it, and restart. Every step reproduced on Windows 11.
> node:events:486
FIXED1 min - No.001
Fix: __dirname is not defined in ES module scope (Node 24)
ES modules don't have __dirname or __filename. The one-line modern fix (import.meta.dirname) and the fallback for older Node, both run on Node 24.
> console.log(path.join(__dirname, "data.json"));
FIXED1 min
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— Nilay