How do I install the Codex Explain skill?

Run npx skillmds@latest add sd0xdev/codex-explain in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

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Which AI agents work with Codex Explain?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Codex Explain free to use?

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Who published Codex Explain?

sd0xdev (@sd0xdev) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Codex Explain by sd0xdev — Agent Skill

Name: Codex Explain
Author: sd0xdev

Codex Explain

Explain complex code via Codex exec. Use when: understanding complex logic, tracing data flow, onboarding to unfamiliar code. Not for: code review (use codex-code-review), exploration (use code-explore). Output: structured explanation at chosen depth.

sd0xdev Updated Sep 17, 2026

File contents

Codex Explain Skill

Trigger

Keywords: explain code, what does this do, how does this work, code walkthrough

When NOT to Use

Code review (use codex-code-review)
Bug investigation (use bug-fix or issue-analyze)
Architecture overview (use code-explore)

Workflow

Read target → [Collect context] → Codex explain → Output explanation

Step 1: Read Target File

Read file content. If --lines specified, extract only that range.

Step 2: Codex Explanation

Dispatch per @skills/codex-code-review/references/codex-transport.md § Start with the explanation prompt. See references/codex-prompt-explain.md.

Depth Levels

Level	Description
brief	One-sentence summary
normal	Functional overview + execution flow + key concepts (default)
deep	+ Design patterns + complexity + issues + dependencies

Output

## Code Explanation: <target>
- **Depth**: brief / normal / deep
- **Summary**: <functional overview>
- **Execution flow**: <key paths>
- **Key concepts**: <patterns, abstractions>

Verification

Codex independently researched project context (imports, callers)
Explanation matches requested depth level
Key concepts are identified and explained

References

Explanation prompt: references/codex-prompt-explain.md

Examples

Input: /codex-explain src/service/order/order.service.ts
Action: Read file → Codex explain (normal) → Functional summary + detailed explanation

Input: /codex-explain src/service/xxx.ts --depth deep
Action: Read file → Codex explain (deep) → Patterns + complexity + issues

Input: /codex-explain src/xxx.ts --lines 50-100
Action: Read lines 50-100 → Codex explain → Focused explanation

---name: codex-explaindescription: Explain complex code via Codex exec. Use when: understanding complex logic, tracing data flow, onboarding to unfamiliar code. Not for: code review (use codex-code-review), exploration (use code-explore). Output: structured explanation at chosen depth.---# Codex Explain Skill## Trigger- Keywords: explain code, what does this do, how does this work, code walkthrough## When NOT to Use- Code review (use `codex-code-review`)- Bug investigation (use `bug-fix` or `issue-analyze`)- Architecture overview (use `code-explore`)## Workflow```Read target → [Collect context] → Codex explain → Output explanation```### Step 1: Read Target FileRead file content. If `--lines` specified, extract only that range.### Step 2: Codex ExplanationDispatch per `@skills/codex-code-review/references/codex-transport.md` § Start with the explanation prompt. See `references/codex-prompt-explain.md`.## Depth Levels| Level | Description || ------ | ---------------------------------------------------- || brief | One-sentence summary || normal | Functional overview + execution flow + key concepts (default) || deep | + Design patterns + complexity + issues + dependencies |## Output```markdown## Code Explanation: <target>- **Depth**: brief / normal / deep- **Summary**: <functional overview>- **Execution flow**: <key paths>- **Key concepts**: <patterns, abstractions>```## Verification- [ ] Codex independently researched project context (imports, callers)- [ ] Explanation matches requested depth level- [ ] Key concepts are identified and explained## References- Explanation prompt: `references/codex-prompt-explain.md`## Examples```Input: /codex-explain src/service/order/order.service.tsAction: Read file → Codex explain (normal) → Functional summary + detailed explanationInput: /codex-explain src/service/xxx.ts --depth deepAction: Read file → Codex explain (deep) → Patterns + complexity + issuesInput: /codex-explain src/xxx.ts --lines 50-100Action: Read lines 50-100 → Codex explain → Focused explanation```

Frequently asked questions