Explain Code Skill: TL;DR, Flow, Gotchas
Every codebase has files everyone is a little afraid of. This skill turns "I don't know what this does" into a structured walkthrough — TL;DR, flow, key concepts, gotchas, reading order — calibrated to whether you're a junior, mid, or senior reader.
Full Prompt
An installable skill that explains unfamiliar code so a teammate can safely modify it. Calibrates depth to the reader's experience level.
What It Does
- Reads before explaining — opens imports and callees to ground the walkthrough
- Calibrates to your level — fewer fundamentals for seniors, more for juniors
- Structures the answer — TL;DR → flow → concepts → gotchas → reading order
- Names gotchas — the subtle places the code breaks when edited
Install in 30 Seconds
Pick your tool above and download the right file:
- Claude Code:
~/.claude/skills/explain-code/SKILL.md - OpenAI Codex CLI: append to
AGENTS.md - Cursor: append to
.cursorrules
Then point it at a file, a function, or a hunk: "Explain auth.middleware.ts for me — mid-level."
Why It's Better Than "Just Ask"
A free-form "explain this" prompt usually produces something between a copy-paste and a textbook chapter. Neither is useful when you need to ship a small fix in an unfamiliar file. This skill enforces the structure good explanations actually take — and refuses to over-explain.
Install once, demystify the next scary file in 60 seconds.