How to Explain a Code Snippet with AI

You opened a file you didn’t write — a regex that looks like keyboard mashing, a clever one-liner, a function with no comments — and you need to know what it does before you touch it. AI is excellent at this; the friction is everything around it. Copying the snippet out to a chat tab, pasting it back as a comment, fixing the formatting. Here’s how to explain code fast, without leaving your editor.

What a good code explanation gives you

“Explain this” can return a useless wall of text or a genuinely helpful breakdown. The good ones cover:

• The purpose — what the code accomplishes, in one sentence, before any detail.
• The how — a step-by-step of the logic, in order.
• The gotchas — edge cases, side effects, assumptions, or anything non-obvious (the part that actually saves you).
• The right depth — a senior dev wants the gotchas; someone learning wants the line-by-line. Say which.

For documentation purposes, you may want it formatted as a docstring or comment block rather than prose — that’s a different ask, and worth specifying. The one rule: the explanation must be accurate to the code shown. AI can confidently misread logic, so for anything load-bearing, verify the explanation against what the code actually does.

The generic method (any AI tool)

1. Select and copy the snippet from your editor.
2. Open ChatGPT, Claude, Gemini, or any AI chat.
3. Paste with a depth-specific instruction:

   “Explain what this code does. Start with a one-sentence purpose, then walk through the logic step by step, and call out any edge cases or side effects:” (For docs: “…and format the explanation as a docstring comment I can paste above the function:”)

4. Read it critically — confirm it matches the actual logic.
5. Copy it back as a comment if you’re documenting; fix the comment formatting the paste mangled.

It works, but the round-trip out of your IDE is a context switch right when you’re deep in the code — and pasting an explanation back as a properly-formatted comment block is its own small chore.

The one-hotkey way with EditSnappy

EditSnappy runs an “Explain what this code does” action directly in your editor:

1. Select the snippet in VS Code, a JetBrains IDE, Sublime, or wherever you code.
2. Trigger “Explain this code” with your hotkey or the quick menu.
3. The explanation streams in — you choose whether it replaces the selection (rare), drops in above it as a comment, or shows in a preview you read and Esc out of, leaving your code untouched.

Crucially, EditSnappy is structure-safe: it understands it’s looking at code, so when you ask for an explanation it won’t mangle your variables, syntax, or surrounding lines. The model’s “Sure, here’s an explanation:” preamble is stripped, and your indentation and comment formatting survive.

Why this is the test most inline AI tools fail

Here’s the thing about coding: your editor — VS Code, JetBrains, anything Electron- or Java-based — is precisely where most inline AI tools silently die. The OS accessibility API they depend on misfires in those environments, so you press the hotkey over your code and nothing happens. For a tool aimed at developers, that’s a fatal flaw, and it’s the single most common complaint about the category.

EditSnappy is built around exactly this. It tries the fast native write, and when it can’t confirm the replace in a split second, it falls back to a clean inject or a one-click “Insert” — so the explanation actually lands in your editor. Working reliably in VS Code and JetBrains isn’t a bonus feature; it’s the reason EditSnappy exists. And because every change is shown before it commits, with your original one keypress away in local history, you never risk an AI edit clobbering working code. One hotkey, Mac and Windows.

Stop tab-switching to understand your own codebase. Start a free trial — no credit card and explain code in your editor. See how to clean up documentation fast for the docs companion, and the task index for everything else.