code-explanation

code-explanation is a skill for Claude Code, Codex from DevelopersGlobal/ai-agent-skills. It costs 34 tokens per session (828 once invoked), scanned A, original, MIT.

A guide for understanding unfamiliar code in layers, from a short summary to deeper details about its purpose, structure, and safe use.

In plain words
What is it for?
Use it when joining an unfamiliar codebase, studying a complex function, debugging existing code, or reviewing an unfamiliar part of a code change.
Why use it?
It helps you understand code you did not write without getting lost in either vague explanations or too much detail.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/developersglobal/ai-agent-skills/code-explanation
Any agent
npx skills add DevelopersGlobal/ai-agent-skills --skill code-explanation
Clone the repo
git clone --depth 1 https://github.com/DevelopersGlobal/ai-agent-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for code-explanation

README.md
[![agentmods](https://agentmods.dev/badge/skills/developersglobal/ai-agent-skills/code-explanation.svg)](https://agentmods.dev/skills/developersglobal/ai-agent-skills/code-explanation)
Your own site
<a href="https://agentmods.dev/skills/developersglobal/ai-agent-skills/code-explanation"><img src="https://agentmods.dev/badge/skills/developersglobal/ai-agent-skills/code-explanation.svg" alt="Measured on agentmods" height="20"></a>
Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 828 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00034 $0.00828
Opus 5 $0.00017 $0.00414
Sonnet 5 $0.00007 $0.00166
Haiku 4.5 $0.00003 $0.00083

Measured 4d ago against content hash d00a8a9be473, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

code-explanation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/code-explanation/SKILL.md · 93 lines

How it starts

The opening of the file, as written. The whole thing — 93 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Overview

Understanding unfamiliar code is a daily engineering task — onboarding to a codebase, debugging a library, or reviewing a PR. AI agents can explain code, but without structure, explanations are either too high-level to be useful or too detailed to absorb.

This skill produces layered, targeted explanations: start with what it does, then why, then how to work with it.

When to Use

  • Onboarding to an unfamiliar codebase
  • Understanding a complex function or algorithm before modifying it
  • Debugging code you didn't write
  • Reviewing a PR for a part of the system you don't know well

Process

Step 1: The 30-Second Summary

  1. In 2–3 sentences: What does this code do? What problem does it solve?
  2. What is the expected input? What is the output/effect?
  3. Where does this fit in the larger system?

Deliver: A 2–3 sentence plain-English summary a junior engineer can understand.

Step 2: Key Concepts and Patterns

  1. What design patterns does this use? (observer, factory, pipeline, etc.)
  2. What external libraries or frameworks are being used and why?
  3. Are there any non-obvious algorithmic choices? (Why O(n log n) and not O(n²)?)
  4. What are the key data structures and why were they chosen?

Deliver: 3–5 bullet points explaining the key design decisions.

Step 3: Execution Walkthrough

  1. Walk through the primary execution path step by step.
  2. For each significant step: what happens? what state changes?
  3. Highlight any surprising or non-obvious behavior.
  4. Show example input → output.

Deliver: A numbered step-by-step walkthrough of the happy path.

Step 4: Edge Cases and Gotchas

  1. What inputs cause unexpected behavior?
  2. What are the performance characteristics? (O(n) per call? Expensive on large inputs?)
  3. What side effects does this have? (Modifies global state? Makes network calls?)
  4. What could go wrong? What does failure look like?

Deliver: A "watch out for" section with at least 2 gotchas.

Step 5: How to Work With This Code Safely

Read the full file on GitHub · 93 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 93 lines · 34 tokens per session scan A d00a8a9be473

Subscribe to this mod's changes

code-explanation is a skill published in the GitHub repository DevelopersGlobal/ai-agent-skills (65 stars, last pushed 4mo ago), licensed MIT. It adds 34 tokens to every session and 828 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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