---
Caveman is a skill/plugin for [Claude Code](https://docs.anthropic.com/en/docs/claude-code), Codex, Gemini, Cursor, Windsurf, Cline, Copilot, and 30+ other agents. Install once. Agent drops the filler and answers in tight caveman-speak, keeping code, commands, and errors byte-for-byte exact. You save output tokens on every reply, forever.
## Before / After
🗣️ Normal agent — 69 tokens
Caveman agent — 19 tokens
> The reason your React component is re-rendering is likely because you're creating a new object reference on each render cycle. When you pass an inline object as a prop, React's shallow comparison sees it as a different object every time, which triggers a re-render. I'd recommend using useMemo to memoize the object.
> New object ref each render. Inline object prop = new ref = re-render. Wrap in `useMemo`.
> Sure! I'd be happy to help you with that. The issue you're experiencing is most likely caused by your authentication middleware not properly validating the token expiry. Let me take a look and suggest a fix.
> Bug in auth middleware. Token expiry check use `<` not `<=`. Fix:
Same fix. Third of the words. Nothing technical lost.
```
┌────────────────────────────────────────────┐
│ output tokens saved █████████ 65% │
│ input tokens saved ░░░░░░░░░ 0% │
│ technical accuracy █████████ 100% │
│ vibes █████████ OOG │
└────────────────────────────────────────────┘
```
Caveman no make brain smaller. Caveman make *mouth* smaller. Shrinks what the agent **says**, not what it knows.
## Install
**One command. Finds every agent on your machine. Installs for each.**
```bash
# macOS · Linux · WSL · Git Bash
curl -fsSL https://raw.githubusercontent.com/JuliusBrussee/caveman/main/install.sh | bash
```
```powershell
# Windows · PowerShell 5.1+
irm https://raw.githubusercontent.com/JuliusBrussee/caveman/main/install.ps1 | iex
```
~30 seconds. Needs Node ≥18. Skips agents you no have. Safe to re-run.
> [!TIP]
> **Turn it on:** type `/caveman` or say *"talk like caveman"*. **Turn it off:** say *"normal mode"*. On Claude Code, Codex, and Gemini it's already on from message one. No command needed.
Install for one agent, or any of 30+ others
Every agent has its own path (plugin, extension, rule file, or `npx skills add`). The full per-agent matrix, all flags, dry-run, and uninstall live in **[INSTALL.md](./INSTALL.md)**. A few common ones:
```bash
# Claude Code plugin
claude plugin marketplace add JuliusBrussee/caveman && claude plugin install caveman@caveman
# Gemini CLI extension
gemini extensions install https://github.com/JuliusBrussee/caveman
# Cursor / Windsurf / Cline / Codex / 30+ more, via the skills registry
npx skills add JuliusBrussee/caveman -a cursor
```
**Install broke?** Open your agent in this repo and say: *"Read CLAUDE.md and INSTALL.md, install caveman for me."* Agent read repo, agent fix own brain. Snake eat tail.
## Pick your grunt
Six levels. Switch anytime with `/caveman `. Level sticks until you change it or the session ends.
| Level | Same sentence, shrunk |
|---|---|
| *normal agent* | You should wrap the object in `useMemo`, since a new reference is created on every render. |
| `lite` | Wrap object in `useMemo`. New ref created every render. |
| `full` *(default)* | New ref each render. Wrap object in `useMemo`. |
| `ultra` | New ref/render. `useMemo` it. |
| `wenyan` | New ref every render, so wrap in `useMemo` — rendered in classical Chinese, shorter still. |
> [!NOTE]
> **Speak your tongue.** Caveman keeps your language. Write Portuguese, caveman grunt Portuguese. Spanish, French, same. It compresses the *style*, never translates. `wenyan` mode is the exception on purpose: classical Chinese packs the most meaning per token.
## What you get
| Command | What it does |
|---|---|
| `/caveman [lite\|full\|ultra\|wenyan]` | Compress every reply. Level sticks for the session. |
| `/caveman-commit` | Conventional Commit messages, ≤50-char subject. Why over what. |
| `/caveman-review` | One-line PR comments: `L42: 🔴 bug: user null. Add guard.` |
| `/caveman-stats` | Real session token usage, lifetime savings, USD. Tweetable line with `--share`. |
| `/caveman-compress ` | Rewrite a memory file (like `CLAUDE.md`) into caveman-speak. Cuts ~46% input tokens **every session after**. Code, URLs, paths byte-preserved. |
| `caveman-shrink` | MCP middleware. Wraps any MCP server, compresses its tool descriptions. [npm](https://www.npmjs.com/package/caveman-shrink). |
| `cavecrew-*` | Caveman subagents (investigator, builder, reviewer). ~60% fewer tokens than vanilla, so main context lasts longer. |
> [!TIP]
> On Claude Code the statusline shows `[CAVEMAN] ⛏ 12.4k` — that's your lifetime tokens saved, updated on every `/caveman-stats`. Silence it with `CAVEMAN_STATUSLINE_SAVINGS=0`.
## Benchmarks
Real token counts from the Claude API. Average **65% output reduction** across 10 prompts (range 22–87%), measured against default verbose replies. Output tokens only, committed and reproducible in [`benchmarks/`](./benchmarks/) and [`evals/`](./evals/).
| Task | Normal | Caveman | Saved |
|------|-------:|--------:|------:|
| Explain React re-render bug | 1180 | 159 | 87% |
| Fix auth middleware token expiry | 704 | 121 | 83% |
| Set up PostgreSQL connection pool | 2347 | 380 | 84% |
| Explain git rebase vs merge | 702 | 292 | 58% |
| Refactor callback to async/await | 387 | 301 | 22% |
| Architecture: microservices vs monolith | 446 | 310 | 30% |
| Review PR for security issues | 678 | 398 | 41% |
| Docker multi-stage build | 1042 | 290 | 72% |
| Debug PostgreSQL race condition | 1200 | 232 | 81% |
| Implement React error boundary | 3454 | 456 | 87% |
| **Average** | **1214** | **294** | **65%** |
> [!IMPORTANT]
> **Honest number warning.** Caveman only shrinks **output** tokens. Input and reasoning tokens are untouched, and the skill itself adds ~1–1.5k input tokens per turn. So whole-session savings run smaller than the output number, and on already-terse workloads they can go net-negative. The real win is **readability and speed**. Cost savings are the bonus. When caveman wins, when it loses, and how to measure it yourself: **[docs/HONEST-NUMBERS.md](./docs/HONEST-NUMBERS.md)**.
Turns out short isn't just cheaper. A March 2026 paper, [*Brevity Constraints Reverse Performance Hierarchies in Language Models*](https://arxiv.org/abs/2604.00025), tested 31 models and found that constraining large models to brief answers **improved accuracy by ~26 points** on some benchmarks. Sometimes less word = more correct.
caveman-compress receipts — real memory files, cutting input tokens forever
| File | Original | Compressed | Saved |
|---|---:|---:|---:|
| `claude-md-preferences.md` | 706 | 285 | **59.6%** |
| `project-notes.md` | 1145 | 535 | **53.3%** |
| `claude-md-project.md` | 1122 | 636 | **43.3%** |
| `todo-list.md` | 627 | 388 | **38.1%** |
| `mixed-with-code.md` | 888 | 560 | **36.9%** |
| **Average** | **898** | **481** | **46%** |
Every session after, that file loads ~46% smaller. Input tokens saved forever, not just one reply.
## The whole cave
### Want the whole agent, not just its mouth? → caveman-code
This skill shrinks what an agent **says**. **[caveman-code](https://github.com/JuliusBrussee/caveman-code)** shrinks **everything** — a full terminal coding agent, caveman top to bottom. **~2× fewer tokens than Codex** on identical tasks. 20+ providers, plan mode, autopilot goal loop, MIT.
```bash
npm install -g @juliusbrussee/caveman-code
```
[**▶ Try caveman-code →**](https://github.com/JuliusBrussee/caveman-code)
Five tools, one idea: **agent do more with less.**
| Repo | What it shrinks |
|------|------|
| [**caveman**](https://github.com/JuliusBrussee/caveman) *(you here)* | What the agent **says** |
| [**caveman-code**](https://github.com/JuliusBrussee/caveman-code) | The **whole agent**, end to end |
| [**cavemem**](https://github.com/JuliusBrussee/cavemem) | What the agent **remembers**, across sessions |
| [**cavekit**](https://github.com/JuliusBrussee/cavekit) | The **build loop** — spec-driven, no guessing |
| [**cavegemma**](https://github.com/JuliusBrussee/finetune-caveman) | The compression **baked into weights** (Gemma fine-tune) |
Also: five sibling skills, one install
[**JuliusBrussee/skills**](https://github.com/JuliusBrussee/skills) — works in Claude Code, Cursor, Gemini, Cline, Copilot, 40+ agents:
| Skill | What |
|------|------|
| [**caveman**](https://github.com/JuliusBrussee/skills/tree/main/skills/caveman) | This one. Speak less, say more. |
| [**grill-me**](https://github.com/JuliusBrussee/skills/tree/main/skills/grill-me) | Agent grills your plan *before* you build the wrong thing. |
| [**interface-kit**](https://github.com/JuliusBrussee/skills/tree/main/skills/interface-kit) | Build UI that looks good, loads fast, works for everyone. |
| [**junior-to-senior**](https://github.com/JuliusBrussee/skills/tree/main/skills/junior-to-senior) | Adversarial review pass. Junior output in, senior output out. |
| [**loop-factory**](https://github.com/JuliusBrussee/skills/tree/main/skills/loop-factory) | Spec-driven task loop — inbox → active → archive. |
```bash
npx skills@latest add JuliusBrussee/skills
```
🦞 Teach the lobster brevity — OpenClaw integration
[**OpenClaw**](https://openclaw.ai) is a self-host gateway: one box, many agents inside, wired to Slack / Discord / iMessage / Telegram. Lobster strong. Lobster smart. Lobster also talk a lot.
Same installer, scoped to one agent:
```bash
curl -fsSL https://raw.githubusercontent.com/JuliusBrussee/caveman/main/install.sh | bash -s -- --only openclaw
```
Two things happen, no more: a caveman skill lands in the workspace, and a tiny marker-fenced block is appended to `SOUL.md` (OpenClaw injects it every turn, so the lobster is terse from message one — no `/caveman` per session). Custom path? `OPENCLAW_WORKSPACE=/your/path`. Uninstall with the same line plus `--uninstall`; your other workspace content stays untouched. Lobster claw still sharp. Lobster mouth now small.
## Caveman 2
**Caveman make token small. Caveman 2 make it _provable_.**
Today's savings numbers (including `/caveman-stats`) are local estimates. Caveman 2 measures and verifies them across a whole team — real receipts, real dashboard, real proof the tokens went down. Building it now.
[**Join the waitlist → caveman.so**](https://caveman.so)
## How it works
1. Install drops a skill file into your agent.
2. Skill tells agent: drop filler, keep substance, use fragments — but never touch code, commands, or errors.
3. On Claude Code, a hook writes a tiny flag file each session, so the agent talks caveman from message one without `/caveman`.
4. `/caveman-stats` reads your session log, counts tokens saved, writes the number to your statusline.
5. `/caveman-compress` rewrites memory files (like `CLAUDE.md`) so every future session starts with a smaller context. Save tokens forever, not just once.
Hook architecture, file ownership, and CI sync are documented for maintainers in [CLAUDE.md](./CLAUDE.md).
## Privacy
Caveman no phone home. No telemetry, no analytics, no accounts, no backend. After install, zero network calls — the skill is a prompt, the hooks are local scripts, and `/caveman-stats` reads a log already on your disk. Install-time fetches (GitHub plus your agents' own registries) are spelled out in [SECURITY.md](./SECURITY.md#privacy--telemetry).
## Sponsors
Caveman free forever. Sponsors keep the rock sharp.
Atlas Cloud — full-modal AI inference platform, one API.
## Star this repo
Caveman save you token, save you money. Star cost zero. Fair trade. ⭐
[](https://star-history.com/#JuliusBrussee/caveman&Date)
---
Docs:Install matrix ·
Honest numbers ·
Contributing ·
Maintainer guide ·
Issues Also by Julius Brussee:Revu — local-first macOS study app with FSRS spaced repetition (revu.cards)