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ljagiello

Ctf Writeup skill

Generates a single standardized submission-style CTF writeup for competition handoff and organizer review. Use after solving a CTF challenge to document the solution steps, tools used, and lessons learned in a structured format.

$npx skills add ljagiello/ctf-skills --skill ctf-writeup
GitHub stars
3,674
Pack installs
107k
Alyn Score
67/99
Updated
3 h ago
License
MIT

ljagiello

Ctf Writeup

Install Ctf Writeup

Pick your agent. Every command is ready to paste.

$npx skills add ljagiello/ctf-skills --skill ctf-writeup

The open skills CLI detects your agents (Claude Code, Cursor, Codex and 70+ more) and installs to the right folder. Add -g to install globally.

01

Install it

Run the command above, or upload the folder in Claude.

02

Ask naturally

Describe the task. Your agent loads ctf-writeup when the request matches its description.

03

Name it if needed

If it does not trigger, say “use the ctf-writeup skill”. In Codex, type $ctf-writeup.

The skill itself

SKILL.md

GitHub

CTF Write-up Generator

Generate a standardized submission-style CTF writeup for a solved challenge.

Default behavior:

  • During an active competition, optimize for speed, clarity, and reproducibility
  • Keep writeups short enough that a teammate or organizer can validate the solve quickly
  • Always produce a submission-style writeup
  • Prefer one complete solve script from challenge data to final flag

Workflow

Step 1: Gather Information

Collect the following from the current session, challenge files, and user input:

  1. Challenge metadata — name, CTF event, category, difficulty, points, flag format
  2. Solution artifacts — exploit scripts, payloads, screenshots, command output
  3. Timeline — key steps taken, dead ends, pivots
# Scan for exploit scripts and artifacts
find . -name '*.py' -o -name '*.sh' -o -name 'exploit*' -o -name 'solve*' | head -20
# Check for flags in output files
grep -rniE '(flag|ctf|eno|htb|pico)\{' . 2>/dev/null

Step 2: Generate Write-up

Write the writeup file as writeup.md (or writeup-<challenge-name>.md) using the submission template below.


Templates

Submission Format

---
title: "<Challenge Name>"
ctf: "<CTF Event Name>"
date: YYYY-MM-DD
category: web|pwn|crypto|reverse|forensics|osint|malware|misc|ai-ml
difficulty: easy|medium|hard
points: <number>
flag_format: "flag{...}"
author: "<your name or team>"
---

# <Challenge Name>

## Summary

<1-2 sentences: what the challenge was and the core technique. Keep it direct.>

## Solution

### Step 1: <Action>

<Explain the key observation in 3-8 short lines. Keep it direct.>

\`\`\`python
<one complete solving script from provided challenge data to printing the final flag>
\`\`\`

### Step 2: <Action> (optional)

<Only add this when a second short step genuinely helps readability, such as separating the core observation from final verification.>

### Step 3: <Action> (optional)

<Use only if the challenge really needs it. Keep the total number of steps small.>

## Flag

\`\`\`
flag{example_flag_here}
\`\`\`

Guidance:

  • Prefer 1-3 short steps total
  • Keep code to the smallest complete solving script
  • Do not split "recover secret", "derive key", and "decrypt flag" into separate partial snippets
  • The script should start from the challenge data and end by printing the flag
  • Avoid long background sections
  • Avoid dead ends unless they explain a key pivot
  • Avoid multiple alternative solves; pick one clean path
  • Redact the flag only if the user explicitly asks for redaction

Best Practices Checklist

Before finalizing the writeup, verify:

  • Metadata complete — title, CTF, date, category, difficulty, points, author all filled
  • Flag handling matches request — keep the real flag unless the user asked for redaction
  • Reproducible steps — a reader can follow your writeup and reproduce the solution
  • Code is runnable — exploit scripts include all imports, correct variable names, and comments
  • No sensitive data — no real credentials, API keys, or private infrastructure details
  • Length stays concise — the writeup is short enough for fast review
  • Tools and versions noted — mention specific tool versions if behavior depends on them
  • Proper attribution — credit teammates, referenced writeups, or tools that were essential
  • Grammar and formatting — consistent heading levels, code blocks have language tags

Quality Guidelines

DO:

  • Explain just enough for fast verification
  • Include one complete solving path, not multiple alternative routes
  • Include one complete script that goes all the way to the final flag
  • Show actual output (truncated if very long) to prove the approach worked
  • Tag code blocks with language (python, bash, sql, etc.)
  • Keep the main path front-loaded so a reader can validate it quickly

DON'T:

  • Copy-paste raw terminal dumps without explanation
  • Paste several partial snippets that force the reader to reconstruct the final solve
  • Leave placeholder text in the final writeup
  • Include irrelevant tangents that don't contribute to the solution
  • Assume the reader knows the specific challenge setup

Challenge

$ARGUMENTS

Tips for Ctf Writeup

  • • Start a fresh session after installing so your agent picks up the new skill.
  • • It is part of a pack with 12 skills. Install only the ones you need with --skill to keep triggers precise.
  • • If two skills overlap, mention the one you want by name.

Questions about Ctf Writeup

What does the Ctf Writeup skill do?

Generates a single standardized submission-style CTF writeup for competition handoff and organizer review. Use after solving a CTF challenge to document the solution steps, tools used, and lessons learned in a structured format.

How do I install Ctf Writeup?

Run "npx skills add ljagiello/ctf-skills --skill ctf-writeup" in your project. The skills CLI installs it for Claude Code, Cursor, Codex and 70+ other agents. In Claude on the web, upload the skill folder as a ZIP under Customize > Skills.

Does Ctf Writeup work in Cursor and Codex?

Yes. Ctf Writeup uses the open SKILL.md format, so it works in Claude Code, Claude, Cursor, OpenAI Codex, Gemini CLI, GitHub Copilot and other agents that support agent skills.

Is Ctf Writeup free?

Ctf Writeup is open source on GitHub under the MIT license. It is free to install; check the license before commercial use.

Who made Ctf Writeup?

Ctf Writeup is published by ljagiello in the ljagiello/ctf-skills repository, together with 11 other skills.

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