ntucool: Skill for Claude Code

.claude/skills/demo-recording/SKILL.md

demo-recording is a skill for Claude Code from kc0506/ntucool. It costs 128 tokens per session (2,016 once invoked), scanned B, original, MIT.

A project-specific recipe for recording terminal demonstrations as GIFs or asciinema files, which are replayable terminal-session recordings.

In plain words
What is it for?
Use it to update the ntucool command-line demo or its interactive MCP/agent demo after project changes.
Why use it?
It keeps demos repeatable and removes personal information from the recorded output.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: mentions Claude Code.

This is kc0506/ntucool's own configuration. It tells Claude Code how to work on ntucool itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything ntucool configures →

Reuse

Borrowing it

Nothing to install: this file belongs to kc0506/ntucool. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/kc0506/ntucool/main/.claude/skills/demo-recording/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/kc0506/ntucool

Made for: Claude Code.

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 demo-recording

README.md
[![agentmods](https://agentmods.dev/badge/skills/kc0506/ntucool/demo-recording.svg)](https://agentmods.dev/skills/kc0506/ntucool/demo-recording)
Your own site
<a href="https://agentmods.dev/skills/kc0506/ntucool/demo-recording"><img src="https://agentmods.dev/badge/skills/kc0506/ntucool/demo-recording.svg" alt="Measured on agentmods" height="20"></a>
Per session 128 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,016 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00128 $0.02016
Opus 5 $0.00064 $0.01008
Sonnet 5 $0.00026 $0.00403
Haiku 4.5 $0.00013 $0.00202

Measured 8d ago against content hash be261d535409, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade B, and why

demo-recording scanned grade B 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 8d ago.

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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

All installed without sudo on this machine:
.claude/skills/demo-recording/SKILL.md · 125 lines

How it starts

The opening of the file, as written. The whole thing — 125 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Demo recording

The demo/ directory has two independent recipes. Both produce a GIF and optionally a .cast for sharing on asciinema.org.

Demo Tool Driver Output
CLI VHS Scripted tape demo/cli.gif
MCP / agent asciinema + agg Interactive — user drives Claude Code demo/mcp.cast + demo/mcp.gif

Pick VHS when the content is fully scriptable and you want a deterministic artifact that re-runs cleanly after every change. Pick asciinema when authenticity matters — real timing, real agent reasoning, real tool calls — which scripting would flatten.

CLI demo (VHS)

demo/
├── cli.tape       VHS script: command sequence + styling
├── record.sh      Entry point — sets PATH, runs vhs
├── bin/cool       Masking wrapper around the real `cool` binary
├── redact.py      Masks personal data on stdout
└── cli.gif        Output

Regenerate: ./demo/record.sh

The script puts demo/bin first on PATH so cool in the tape resolves to the masking wrapper. The wrapper finds the real cool by scanning PATH minus its own directory, then pipes stdout through redact.py.

Tweaking commands shown. Edit the Type "cool ..." blocks in cli.tape. Each follows the pattern Type / Sleep / Enter / Sleep — the first sleep lets viewers register the command, the second lets them read the output.

Tweaking styling. The Set block at the top of cli.tape controls FontSize, Theme, WindowBar, BorderRadius, Margin, etc. The current theme is Catppuccin Mocha; vhs themes lists alternatives.

MCP demo (asciinema + agg)

demo/
├── record-mcp.sh    Entry point — prints prompts, records, redacts, renders
├── redact_cast.py   Applies redact.py to each output event of a .cast
├── mcp.raw.cast     Pre-redaction recording (review then delete)
├── mcp.cast         Redacted recording (shareable)
└── mcp.gif          Rendered GIF

Record: ./demo/record-mcp.sh

The script:

  1. Prints three suggested prompts and pauses for confirmation.
  2. Launches asciinema rec --command "claude --dangerously-skip-permissions" so the recording IS the Claude Code session — when the user /exits, recording stops.
  3. Pipes the raw cast through redact_cast.py.
  4. Greps the redacted cast for residual PII and warns if anything leaked across event chunks.
  5. Runs agg to render the GIF.

Read the full file on GitHub · 125 lines

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. 8d ago First seen · 125 lines · 128 tokens per session scan B be261d535409

Subscribe to this mod's changes

demo-recording is a skill published in the GitHub repository kc0506/ntucool (10 stars, last pushed 1mo ago), licensed MIT. It adds 128 tokens to every session and 2,016 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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