notebook

notebook is a skill for Claude Code from catcatcatstudio/cat-skills. It costs 54 tokens per session (5,788 once invoked), scanned A, original, MIT.

A project-notes system that records decisions, constraints, lessons, and progress for future coding-agent sessions.

In plain words
What is it for?
Use it to initialize project notes, save progress during a task, recover context, clean up messy notes, and record lessons from failures.
Why use it?
It prevents each new session from starting without the context discovered by earlier work.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter. Also seen: mentions CLAUDE.md; installed under .agents/ (shared by several agents).

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/catcatcatstudio/cat-skills/notebook
Any agent
npx skills add catcatcatstudio/cat-skills --skill notebook
Clone the repo
git clone --depth 1 https://github.com/catcatcatstudio/cat-skills

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 notebook

README.md
[![agentmods](https://agentmods.dev/badge/skills/catcatcatstudio/cat-skills/notebook.svg)](https://agentmods.dev/skills/catcatcatstudio/cat-skills/notebook)
Your own site
<a href="https://agentmods.dev/skills/catcatcatstudio/cat-skills/notebook"><img src="https://agentmods.dev/badge/skills/catcatcatstudio/cat-skills/notebook.svg" alt="Measured on agentmods" height="20"></a>
Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,788 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 5.1 $0.00054 $0.05788
Opus 5 $0.00027 $0.02894
Sonnet 5 $0.00011 $0.01158
Haiku 4.5 $0.00005 $0.00579

Measured 5d ago against content hash ed7fc420f175, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

notebook 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 5d 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.

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.

.agents/skills/notebook/SKILL.md · 474 lines

How it starts

The opening of the file, as written. The whole thing — 474 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Notebook

Project trail system. Initialize, save, recover, migrate, and manage project notes.

Why this exists

You are stateless. Every conversation ends and your context dies. The next agent that opens this project starts from zero — re-reads code, re-discovers constraints, re-makes mistakes you already made. The human becomes a context shuttle between amnesiac agents.

Notebook makes the project remember so you don't have to. When you save a note, you're not journaling — you're leaving a breadcrumb for a future version of yourself that has no idea what happened here. Every failure you record is a loop you prevent. Every constraint you document is a dead end the next session skips. Every decision you capture is an argument that never gets re-litigated.

The index and lessons files are designed to be fast to scan — a future agent can recover full project context in seconds instead of minutes of re-exploration. This is the difference between an agent that compounds knowledge across sessions and one that starts over every time.

Save aggressively. The cost of a note you didn't need is near zero. The cost of a note you didn't write is another wasted session.

When NOT to use this skill

  • No active project context (no git repo, no project root) — say so, don't create a floating notebook
  • User wants to summarize or extract knowledge from content — use /eat instead
  • Notes already exist and user just wants to read them — read directly with Read tool, skip the skill

Quick Reference

Proactive save rule: Save after every significant decision, failure, or constraint discovered — without being asked. Every ~20 tool calls without a save is too long. If you would say "I should remember this," write it now.

Command Action
/notebook Init (new project) or status (existing)
/notebook save Sweep the WHOLE conversation and write every unsaved insight, each as its own note — never prompts, just writes
/notebook save resolved: <desc> Save a note and resolve the matching lesson
/notebook recover Read index + lessons + flagged notes, summarize state — up the whole chain
/notebook migrate [path] Convert messy notes into notebook format
/notebook split <dir> Give a sub-project its own notebook and move its notes there — proposes, you confirm

Read the full file on GitHub · 474 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. 5d ago First seen · 474 lines · 54 tokens per session scan A ed7fc420f175

Subscribe to this mod's changes

notebook is a skill published in the GitHub repository catcatcatstudio/cat-skills (3 stars, last pushed 9d ago), licensed MIT. It adds 54 tokens to every session and 5,788 once invoked, about $0.0003 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 2026-08-31.

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