Cortex: Skill for Claude Code

.agents/skills/caveman-compress/SKILL.md

caveman-compress is a skill for Claude Code, Codex from igrechuhin/Cortex. It costs 43 tokens per session (1,118 once invoked), scanned A, a copy of caveman-compress, MIT.

A tool for compressing natural-language Markdown files such as agent instructions, memory files, or task lists into shorter Caveman-form text. It keeps a readable backup outside the source directory and validates the result.

In plain words
What is it for?
Use it to compress a specified memory or task file, retry limited validation fixes, or leave the original unchanged when compression fails.
Why use it?
It reduces the amount of text loaded into an agent's input while preserving a human-readable original if something goes wrong.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions CLAUDE.md; installed under .agents/ (shared by several agents).

This is igrechuhin/Cortex's own configuration. It tells Claude Code and Codex how to work on Cortex 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 Cortex configures →

Reuse

Borrowing it

Nothing to install: this file belongs to igrechuhin/Cortex. 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/igrechuhin/Cortex/main/.agents/skills/caveman-compress/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/igrechuhin/Cortex

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 caveman-compress

README.md
[![agentmods](https://agentmods.dev/badge/skills/igrechuhin/cortex/caveman-compress/github.svg)](https://agentmods.dev/skills/igrechuhin/cortex/caveman-compress)
Your own site
<a href="https://agentmods.dev/skills/igrechuhin/cortex/caveman-compress"><img src="https://agentmods.dev/badge/skills/igrechuhin/cortex/caveman-compress/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for caveman-compress

Your own site · 80×15
<a href="https://agentmods.dev/skills/igrechuhin/cortex/caveman-compress"><img src="https://agentmods.dev/badge/skills/igrechuhin/cortex/caveman-compress.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,118 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod 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 $0.00043 $0.01118
Opus 5.5 $0.00017 $0.00447
Sonnet 5.5 $0.00009 $0.00224
Haiku 4.5 $0.00004 $0.00112

Measured 1mo ago against content hash 377b0b8682d9, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

caveman-compress 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 1mo ago.

The scan reads SKILL.md. This mod also ships 7 executable files (scripts/__init__.py, scripts/__main__.py, scripts/benchmark.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Origin

This is a copy

100% identical to caveman-compress — 7 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/caveman-compress/SKILL.md · 110 lines

How it starts

The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Caveman Compress

Purpose

Compress natural language files (CLAUDE.md, todos, preferences) into caveman-speak to reduce input tokens. Compressed version overwrites original. Human-readable backup saved as <filename>.original.md, but NOT beside the source file — it lives in an out-of-tree data dir ($XDG_DATA_HOME/caveman-compress/backups/<parent-dir-name>/, or %LOCALAPPDATA%\caveman-compress\backups\<parent-dir-name>\ on Windows) so skill auto-loaders don't re-ingest it as a live file.

Trigger

/caveman-compress <filepath> or when user asks to compress a memory file.

Process

  1. The compression scripts live in scripts/ (adjacent to this SKILL.md). If the path is not immediately available, search for scripts/__main__.py next to this SKILL.md.

  2. From the directory containing this SKILL.md, run:

python3 -m scripts <absolute_filepath>

  1. The CLI will:
  • detect file type (no tokens)
  • call Claude to compress
  • validate output (no tokens)
  • if errors: cherry-pick fix with Claude (targeted fixes only, no recompression)
  • retry up to 2 times
  • if still failing after 2 retries: report error to user, leave original file untouched
  1. Return result to user

Compression Rules

Remove

  • Articles: a, an, the
  • Filler: just, really, basically, actually, simply, essentially, generally
  • Pleasantries: "sure", "certainly", "of course", "happy to", "I'd recommend"
  • Hedging: "it might be worth", "you could consider", "it would be good to"
  • Redundant phrasing: "in order to" → "to", "make sure to" → "ensure", "the reason is because" → "because"
  • Connective fluff: "however", "furthermore", "additionally", "in addition"

Preserve EXACTLY (never modify)

  • Code blocks (fenced ``` and indented)
  • Inline code (backtick content)
  • URLs and links (full URLs, markdown links)
  • File paths (/src/components/..., ./config.yaml)
  • Commands (npm install, git commit, docker build)
  • Technical terms (library names, API names, protocols, algorithms)
  • Proper nouns (project names, people, companies)
  • Dates, version numbers, numeric values
  • Environment variables ($HOME, NODE_ENV)

Read the full file on GitHub · 110 lines

Files

What ships with it

9 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 1mo ago First seen · 110 lines · 43 tokens per session scan A 377b0b8682d9

Subscribe to this mod's changes

caveman-compress is a skill published in the GitHub repository igrechuhin/Cortex (3 stars, last pushed 3d ago), licensed MIT. It adds 43 tokens to every session and 1,118 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to caveman-compress, differing in 7 lines, and is treated as a copy.

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