ctf-writeup
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.
- Installs
- 7.9K
- Last 24h
- +37
- Trending rank
- #4028
- Security
- Pass
Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/ljagiello/ctf-skills --skill ctf-writeup- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads ctf-writeup automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
Security audits
Independent scans of the skill's instructions and bundled files.
SKILL.md
The instructions your agent reads when the skill is triggered.
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:
- Challenge metadata — name, CTF event, category, difficulty, points, flag format
- Solution artifacts — exploit scripts, payloads, screenshots, command output
- 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
FAQ
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 https://github.com/ljagiello/ctf-skills --skill ctf-writeup in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/ctf-writeup/ (personal) or .claude/skills/ctf-writeup/ (project).
Which AI agents can use ctf-writeup?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is ctf-writeup safe to install?
Security partners have reviewed it: Gen Agent Trust Hub passed; Socket passed; Snyk passed; ZeroLeaks passed. As with any skill, read the SKILL.md and bundled scripts before installing.
Who maintains ctf-writeup?
It is published by ljagiello in ljagiello/ctf-skills. It has 7,917 recorded installs.
More from ljagiello/ctf-skills
ctf-reverse
ljagiello/ctf-skills
Provides reverse engineering techniques for CTF challenges. Use when the main job is to understand how a compiled, obfuscated, packed, or virtualized target works before exploiting or solving it, including binaries, APKs, WASM, firmware, custom VMs, bytecode, game clients, malware-like loaders, and anti-debug or anti-analysis logic. Do not use it when the vulnerability is already understood and the remaining task is exploitation; use pwn instead. Do not use it for pure web workflows, log or disk forensics, or standalone crypto problems unless reversing the implementation is the real blocker.
ctf-web
ljagiello/ctf-skills
Provides web exploitation techniques for CTF challenges. Use when the target is primarily an HTTP application, API, browser client, template engine, identity flow, or smart-contract frontend/backend surface, including XSS, SQLi, SSTI, SSRF, XXE, JWT, auth bypass, file upload, request smuggling, OAuth/OIDC, SAML, prototype pollution, and similar web bugs. Do not use it for native binary memory corruption, reverse engineering of standalone executables, disk or memory forensics, or pure cryptanalysis unless the web flaw is still the main path to the flag.
ctf-pwn
ljagiello/ctf-skills
Provides binary exploitation techniques for CTF challenges. Use when you already have a vulnerable native target or service and need to turn memory corruption or low-level primitives into code execution or privilege escalation, such as buffer overflows, format strings, heap bugs, ROP, ret2libc, shellcode, kernel exploitation, seccomp bypass, sandbox escape, or Windows/Linux exploit chains. Do not use it when the main blocker is understanding what the binary does; use reverse engineering first. Do not use it for pure web bugs, disk or packet forensics, or standalone crypto/math challenges.
ctf-crypto
ljagiello/ctf-skills
Provides cryptography attack techniques for CTF challenges. Use when attacking encryption, hashing, signatures, ZKP, PRNG, or mathematical crypto problems involving RSA, AES, ECC, lattices, LWE, CVP, number theory, Coppersmith, Pollard, Wiener, padding oracle, GCM, key derivation, or stream/block cipher weaknesses.
ctf-osint
ljagiello/ctf-skills
Provides open source intelligence techniques for CTF challenges. Use when gathering information from public sources, social media, geolocation, DNS records, username enumeration, reverse image search, Google dorking, Wayback Machine, Tor relays, FEC filings, or identifying unknown data like hashes and coordinates.
ctf-forensics
ljagiello/ctf-skills
Provides digital forensics and signal analysis techniques for CTF challenges. Use when analyzing disk images, memory dumps, event logs, network captures, cryptocurrency transactions, steganography, PDF analysis, Windows registry, Volatility, PCAP, Docker images, coredumps, side-channel power traces, DTMF audio spectrograms, packet timing analysis, CD audio disc images, or recovering deleted files and credentials.
Popular code quality & workflow skills
grill-me
mattpocock/skills
A relentless interview to sharpen a plan or design.
improve-codebase-architecture
mattpocock/skills
Scan a codebase for deepening opportunities, present them as a visual HTML report, then grill through whichever one you pick.
handoff
mattpocock/skills
Compact the current conversation into a handoff document for another agent to pick up.
domain-modeling
mattpocock/skills
Build and sharpen a project's domain model. Use when discussing codebase terminology, writing or editing a GLOSSARY.md, or recording or editing an ADR.
codebase-design
mattpocock/skills
Shared vocabulary for designing deep modules. Use when the user wants to design or improve a module's interface, find deepening opportunities, decide where a seam goes, make code more testable or AI-navigable, or when another skill needs the deep-module vocabulary.
diagnosing-bugs
mattpocock/skills
Diagnosis loop for hard bugs and performance regressions. Use when the user says "diagnose"/"debug this", or reports something broken/throwing/failing/slow.