Three Plain-English Bug Reports

You do not need to know what is wrong before you ask. You do not need to read a stack trace, set a breakpoint, or step through code line by line.

Tell Claude what should be happening. Tell Claude what is actually happening. Let Claude find the gap between them, because the gap is where the bug lives, and Claude is exceptionally good at finding gaps across multiple files at once.

These three are the exact reports from the lecture, and they cover the three kinds of bug you will meet. Copy the shape, not the words.

A visible bug, where part of the thing still works

The dark mode toggle is not working. When I click the button, the icon flips like it heard the click, but the page colors do not change at all. The theme just stays light.

Naming what still works is doing real diagnostic work for Claude. The icon flipping while the colours stay frozen is the tell, and Claude reasoned from that symptom before it opened a single file: something is checking for one theme name while something else sets a different one.

That mismatched word might take you five to ten minutes to find by eye, scrolling between two files trying to spot what does not line up.

A quiet bug, with no error message anywhere

When I click on a project to see more about it, nothing happens. No popup, no bigger view, nothing. The cards look totally normal, they just do not respond to clicks.

Nothing turns red. Nothing complains. The only sign anything is wrong is that a thing you expected to happen does not. That is the quiet kind, and it takes the longest to chase down alone, because there is no error message pointing the way.

A loud bug, with console errors

Console Error [[Uncaught TypeError: Cannot read properties of null (reading 'classList')
index.html#contact:1 Unsafe attempt to load URL file:///.../portfolio/index.html#contact from frame with URL file:///.../portfolio/index.html#contact. 'file:' URLs are treated as unique security origins.]]
After my last edit, a whole bunch of things stopped working at once. The back-to-top button never shows, clicking projects does nothing, the nav stops highlighting, and the animated headline just shows as plain text instead of typing itself out. The console shows this error. The dark mode and the menu still work fine though.

Two things to copy from that last one.

The format. The pasted console output goes inside double brackets so it reads as one block, and your plain-English description follows it.

Do not sort the useful error from the noise yourself. Two errors were pasted there and only one mattered. Separating signal from noise is work Claude does better than you, and it filtered the irrelevant one without being asked or even mentioning it.

Why one typo took down half the page

The diagnosis on that last bug started from the pattern of what survived, not from the error. Dark mode and the menu ran first and were alive. Everything from the back-to-top button onward was dead. That pointed at one setup function before a single file was open.

The page wires its features up one after another, in a line. When one throws an error, the browser stops, and everything later in that line never gets to run. So a single mistake in one spot can look like half the page breaking, when really it is one bug standing in the doorway.

The pattern, every time

Tell Claude what should be happening. Tell Claude what is actually happening. Let Claude compare the code against your expectations.

That works tonight, it works in three years, and it works on somebody else's project in a language you have never used.

This resource is part of

Claude Code: From Beginner to Pro Agentic AI Engineer

by Arun Nagarathanam

Take your skills to the next level with

AI GEO 2026: Get Recommended by ChatGPT, Google, Perplexity

by Arun Nagarathanam