ctf

ctf is a skill for Claude Code, Codex from asaotomo/DeepSentry. It costs 33 tokens per session (544 once invoked), scanned A, original, Apache-2.0.

A workflow for solving Capture the Flag (CTF) security exercises using web pages, files, logs, and network clues. A CTF is an authorized challenge where participants find hidden answers called flags.

In plain words
What is it for?
Use it to inspect rendered web pages, search files and directories, analyze logs and traffic, find flags, document tried paths, and explain the evidence behind a solution.
Why use it?
It organizes investigations around the type of challenge and requires each conclusion to be tied to evidence. It also keeps the work within authorized labs or local files and avoids attacking public systems.

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/asaotomo/deepsentry/ctf
Any agent
npx skills add asaotomo/DeepSentry --skill ctf
Clone the repo
git clone --depth 1 https://github.com/asaotomo/DeepSentry

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 ctf

README.md
[![agentmods](https://agentmods.dev/badge/skills/asaotomo/deepsentry/ctf.svg)](https://agentmods.dev/skills/asaotomo/deepsentry/ctf)
Your own site
<a href="https://agentmods.dev/skills/asaotomo/deepsentry/ctf"><img src="https://agentmods.dev/badge/skills/asaotomo/deepsentry/ctf.svg" alt="Measured on agentmods" height="20"></a>
Per session 33 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 544 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 $0.00033 $0.00544
Opus 5 $0.00016 $0.00272
Sonnet 5 $0.00007 $0.00109
Haiku 4.5 $0.00003 $0.00054

Measured today against content hash 2a626e1e0606, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ctf 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 today.

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/ctf/SKILL.md · 46 lines

What it actually says

CTF Skill

何时使用

  • 用户明确提到 CTF、flag、题目附件、Web 题、Misc、取证、日志分析。
  • 需要在授权靶场或本地题目环境中查找 flag 或解释解题路径。

工作流

  1. 明确题型、输入材料和授权范围;不要扫描第三方公网目标。
  2. Web 题优先使用 headless_browser 获取渲染后 DOM、表单、链接和文本;失败时接受静态回退。
  3. 加密 ZIP 先 load_skill zipcracker,再用 zip_password_recoveraction=auto 会按 ZipCracker 顺序先修伪加密,再对 1~6 字节条目做 CRC32 内容恢复,最后用内置 6000 字典。不要把 CRC32 命中的明文当成密码。已知明文/bkcrack 尚未复刻。
  4. 文件/目录题优先 globgrepfile_identfile_stringsflag_scan
  5. 日志/取证题优先 read_logread_gziplog-analyst 子 Agent。
  6. 每个结论必须绑定证据:路径、URL、匹配片段、响应状态或日志时间。

推荐工具

{"action":"tool","tool_name":"tool_catalog","tool_args":{"category":"Web探测","query":"headless"}}
{"action":"tool","tool_name":"headless_browser","tool_args":{"url":"http://127.0.0.1:8080","mode":"snapshot","wait_ms":"1500"}}
{"action":"tool","tool_name":"flag_scan","tool_args":{"root":".","limit":"80"}}

输出格式

## CTF 分析结果
### 题型判断
### 关键证据
### 已尝试路径
### Flag / 当前最佳结论
### 下一步

边界

  • 不自动爆破真实账号,不做未授权公网攻击。
  • 需要写脚本时先说明脚本目的、输入、输出和读写边界,再用 script_run 请求确认。
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. today Changed · +1 lines 2a626e1e0606
  2. 4d ago First seen · 45 lines · 33 tokens per session scan A 2e817cde9647

Subscribe to this mod's changes

ctf is a skill published in the GitHub repository asaotomo/DeepSentry (24 stars, last pushed today), licensed Apache-2.0. It adds 33 tokens to every session and 544 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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