ctf

A coordinator for capture-the-flag (CTF) security competitions, where participants solve puzzles involving systems and code. It sorts challenges by subject and passes them to helpers focused on areas such as web security, cryptography, files, or binary programs.

In plain words
What is it for?
Use it to classify CTF challenges and delegate them to specialists in web, cryptography, forensics, binary exploitation, reverse engineering, miscellaneous, or combined challenges.
Why use it?
It provides a starting point when a challenge could involve several security topics. This avoids having to decide manually which specialist should investigate it first.

Agent

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 agents/zebbern/termstack/ctf
Clone the repo
git clone --depth 1 https://github.com/zebbern/termstack
Per session 53 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 12,385 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin unknown 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 $0.00053 $0.12385
Opus 5 $0.00026 $0.06193
Sonnet 5 $0.00011 $0.02477
Haiku 4.5 $0.00005 $0.01239

Measured yesterday against content hash 177631a5927a, 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 1 finding 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 yesterday.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

Use the Kali MCP CTF tools for all CTFd platform interaction. **Never use raw curl commands when MCP tools are available.**
.github/agents/ctf.agent.md · 1,095 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. yesterday First seen · 1,095 lines · 53 tokens per session scan A 177631a5927a

Subscribe to this mod's changes

ctf is an agent published in the GitHub repository zebbern/termstack (5 stars, last pushed 4mo ago), with no licence file. It adds 53 tokens to every session and 12,385 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.