code-explainer

# Code Explainer Skill Make unfamiliar code understandable — fast — without dumbing it down. ## Working from a brief Infer the language and intent from the code itself; label assumptions *(assumed — confirm)*. Always produce a complete explanation even from a fragment. Match depth to the apparent level of the question. ## Input Ask for these if not provided: - **The code** — the snippet or file to explain (paste it, or point at the path) - **The language or runtime** — if it is not obvious from the code - **The reader** — who this is for and how much they already know - **What they are trying to understand** — the bug, the review, the handover; infer the rest ## Output Structure ### In one line What this code does, in a single sentence a busy reader can repeat. ### Step by step A walkthrough of the logic in order — group by block/function. Explain *why*, not just *what*, for anything non-trivial. Reference line ranges where helpful. ### Worth knowing The non-obvious bits: clever tricks, gotchas, side effects, complexity, dependencies, or assumptions the code makes. ### Anything off? Bugs, edge cases, or smells you noticed while reading — with the fix. (If it's clean, say so.) ## Quality Checks - [ ] The one-line summary stands alone - [ ] The walkthrough explains *why*, not just restating the code in words - [ ] Non-obvious behaviour (side effects, complexity, edge cases) is surfaced - [ ] Any bug/smell spotted is flagged with a fix ## Anti-Patterns - [ ] Do not narrate line-by-line in English ("this line sets x to 5") — explain intent and structure - [ ] Do not skip the gotchas — the value is in the non-obvious parts - [ ] Do not assume expert level if the question reads like a beginner's (or vice-versa) - [ ] Do not ignore a bug you can see just because you weren't asked to review it