why use many token when few do trick
Before/After • Install • Levels • Skills • Benchmarks • Evals
🪨 Caveman Ecosystem · caveman talk less (you are here) · cavemem remember more · cavekit build better
A Claude Code skill/plugin and Codex plugin that makes agent talk like caveman — cutting ~75% of output tokens while keeping full technical accuracy. Now with 文言文 mode, terse commits, one-line code reviews, and a compression tool that cuts ~46% of input tokens every session.
Based on the viral observation that caveman-speak dramatically reduces LLM token usage without losing technical substance. So we made it a one-line install.
|
|
|
|
Same fix. 75% less word. Brain still big.
Pick your level of grunt:
|
|
|
|
Same answer. You pick how many word.
┌─────────────────────────────────────┐
│ TOKENS SAVED ████████ 75% │
│ TECHNICAL ACCURACY ████████ 100%│
│ SPEED INCREASE ████████ ~3x │
│ VIBES ████████ OOG │
└─────────────────────────────────────┘
- Faster response — less token to generate = speed go brrr
- Easier to read — no wall of text, just the answer
- Same accuracy — all technical info kept, only fluff removed (science say so)
- Save money — ~71% less output token = less cost
- Fun — every code review become comedy
Pick your agent. One command. Done.
| Agent | Install |
|---|---|
| Claude Code | claude plugin marketplace add JuliusBrussee/caveman && claude plugin install caveman@caveman |
| Codex | Clone repo → /plugins → Search "Caveman" → Install |
| Gemini CLI | gemini extensions install https://github.com/JuliusBrussee/caveman |
| Cursor | npx skills add JuliusBrussee/caveman -a cursor |
| Windsurf | npx skills add JuliusBrussee/caveman -a windsurf |
| Copilot | npx skills add JuliusBrussee/caveman -a github-copilot |
| Cline | npx skills add JuliusBrussee/caveman -a cline |
| Any other | npx skills add JuliusBrussee/caveman |
Install once. Use in every session for that install target after that. One rock. That it.
Auto-activation is built in for Claude Code, Gemini CLI, and the repo-local Codex setup below. npx skills add installs the skill for other agents, but does not install repo rule/instruction files, so Caveman does not auto-start there unless you add the always-on snippet below.
| Feature | Claude Code | Codex | Gemini CLI | Cursor | Windsurf | Cline | Copilot |
|---|---|---|---|---|---|---|---|
| Caveman mode | Y | Y | Y | Y | Y | Y | Y |
| Auto-activate every session | Y | Y¹ | Y | —² | —² | —² | —² |
/caveman command |
Y | Y¹ | Y | — | — | — | — |
| Mode switching (lite/full/ultra) | Y | Y¹ | Y | Y³ | Y³ | — | — |
| Statusline badge | Y⁴ | — | — | — | — | — | — |
| caveman-commit | Y | — | Y | Y | Y | Y | Y |
| caveman-review | Y | — | Y | Y | Y | Y | Y |
| caveman-compress | Y | Y | Y | Y | Y | Y | Y |
| caveman-help | Y | — | Y | Y | Y | Y | Y |
Note
Auto-activation works differently per agent: Claude Code uses SessionStart hooks, this repo's Codex dogfood setup uses .codex/hooks.json, Gemini uses context files. Cursor/Windsurf/Cline/Copilot can be made always-on, but npx skills add installs only the skill, not the repo rule/instruction files.
¹ Codex uses $caveman syntax, not /caveman. This repo ships .codex/hooks.json, so caveman auto-starts when you run Codex inside this repo. The installed plugin itself gives you $caveman; copy the same hook into another repo if you want always-on behavior there too. caveman-commit and caveman-review are not in the Codex plugin bundle — use the SKILL.md files directly.
² Add the "Want it always on?" snippet below to those agents' system prompt or rule file if you want session-start activation.
³ Cursor and Windsurf receive the full SKILL.md with all intensity levels. Mode switching works on-demand via the skill; no slash command.
⁴ Available in Claude Code, but plugin install only nudges setup. Standalone install.sh / install.ps1 configures it automatically when no custom statusLine exists.
Claude Code — full details
The plugin install gives you skills + auto-loading hooks. If no custom statusLine is configured, Caveman nudges Claude to offer badge setup on first session.
claude plugin marketplace add JuliusBrussee/caveman
claude plugin install caveman@cavemanStandalone hooks (without plugin): If you prefer not to use the plugin system:
# macOS / Linux / WSL
bash <(curl -s https://raw.githubusercontent.com/JuliusBrussee/caveman/main/hooks/install.sh)
# Windows (PowerShell)
irm https://raw.githubusercontent.com/JuliusBrussee/caveman/main/hooks/install.ps1 | iexOr from a local clone: bash hooks/install.sh / powershell -File hooks\install.ps1
Uninstall: bash hooks/uninstall.sh or powershell -File hooks\uninstall.ps1
Statusline badge: Shows [CAVEMAN], [CAVEMAN:ULTRA], etc. in your Claude Code status bar.
- Plugin install: If you do not already have a custom
statusLine, Claude should offer to configure it on first session - Standalone install: Configured automatically by
install.sh/install.ps1unless you already have a custom statusline - Custom statusline: Installer leaves your existing statusline alone. See
hooks/README.mdfor the merge snippet
Codex — full details
macOS / Linux:
- Clone repo → Open Codex in the repo directory →
/plugins→ Search "Caveman" → Install - Repo-local auto-start is already wired by
.codex/hooks.json+.codex/config.toml
Windows:
- Enable symlinks first:
git config --global core.symlinks true(requires Developer Mode or admin) - Clone repo → Open VS Code → Codex Settings → Plugins → find "Caveman" under local marketplace → Install → Reload Window
- Codex hooks are currently disabled on Windows, so use
$cavemanto start manually
This repo also ships .codex/hooks.json and enables hooks in .codex/config.toml, so caveman auto-activates while you run Codex inside this repo on macOS/Linux. The installed plugin gives you $caveman; if you want always-on behavior in other repos too, copy the same SessionStart hook there and enable:
[features]
codex_hooks = trueGemini CLI — full details
gemini extensions install https://github.com/JuliusBrussee/cavemanUpdate: gemini extensions update caveman · Uninstall: gemini extensions uninstall caveman
Auto-activates via GEMINI.md context file. Also ships custom Gemini commands:
/caveman— switch intensity level (lite/full/ultra/wenyan)/caveman-commit— generate terse commit message/caveman-review— one-line code review
Cursor / Windsurf / Cline / Copilot — full details
npx skills add installs the skill file only — it does not install the agent's rule/instruction file, so caveman does not auto-start. For always-on, add the "Want it always on?" snippet below to your agent's rules or system prompt.
| Agent | Command | Not installed | Mode switching | Always-on location |
|---|---|---|---|---|
| Cursor | npx skills add JuliusBrussee/caveman -a cursor |
.cursor/rules/caveman.mdc |
Y | Cursor rules |
| Windsurf | npx skills add JuliusBrussee/caveman -a windsurf |
.windsurf/rules/caveman.md |
Y | Windsurf rules |
| Cline | npx skills add JuliusBrussee/caveman -a cline |
.clinerules/caveman.md |
— | Cline rules or system prompt |
| Copilot | npx skills add JuliusBrussee/caveman -a github-copilot |
.github/copilot-instructions.md + AGENTS.md |
— | Copilot custom instructions |
Uninstall: npx skills remove caveman
Copilot works with Chat, Edits, and Coding Agent.
Any other agent (opencode, Roo, Amp, Goose, Kiro, and 40+ more)
npx skills supports 40+ agents:
npx skills add JuliusBrussee/caveman # auto-detect agent
npx skills add JuliusBrussee/caveman -a amp
npx skills add JuliusBrussee/caveman -a augment
npx skills add JuliusBrussee/caveman -a goose
npx skills add JuliusBrussee/caveman -a kiro-cli
npx skills add JuliusBrussee/caveman -a roo
# ... and many moreUninstall: npx skills remove caveman
Windows note:
npx skillsuses symlinks by default. If symlinks fail, add--copy:npx skills add JuliusBrussee/caveman --copy
Important: These agents don't have a hook system, so caveman won't auto-start. Say /caveman or "talk like caveman" to activate each session.
Want it always on? Paste this into your agent's system prompt or rules file — caveman will be active from the first message, every session:
Terse like caveman. Technical substance exact. Only fluff die.
Drop: articles, filler (just/really/basically), pleasantries, hedging.
Fragments OK. Short synonyms. Code unchanged.
Pattern: [thing] [action] [reason]. [next step].
ACTIVE EVERY RESPONSE. No revert after many turns. No filler drift.
Code/commits/PRs: normal. Off: "stop caveman" / "normal mode".
Where to put it:
| Agent | File |
|---|---|
| opencode | .config/opencode/AGENTS.md |
| Roo | .roo/rules/caveman.md |
| Amp | your workspace system prompt |
| Others | your agent's system prompt or rules file |
Trigger with:
/cavemanor Codex$caveman- "talk like caveman"
- "caveman mode"
- "less tokens please"
Stop with: "stop caveman" or "normal mode"
| Level | Trigger | What it do |
|---|---|---|
| Lite | /caveman lite |
Drop filler, keep grammar. Professional but no fluff |
| Full | /caveman full |
Default caveman. Drop articles, fragments, full grunt |
| Ultra | /caveman ultra |
Maximum compression. Telegraphic. Abbreviate everything |
Classical Chinese literary compression — same technical accuracy, but in the most token-efficient written language humans ever invented.
| Level | Trigger | What it do |
|---|---|---|
| Wenyan-Lite | /caveman wenyan-lite |
Semi-classical. Grammar intact, filler gone |
| Wenyan-Full | /caveman wenyan |
Full 文言文. Maximum classical terseness |
| Wenyan-Ultra | /caveman wenyan-ultra |
Extreme. Ancient scholar on a budget |
Level stick until you change it or session end.
/caveman-commit — terse commit messages. Conventional Commits. ≤50 char subject. Why over what.
/caveman-review — one-line PR comments: L42: 🔴 bug: user null. Add guard. No throat-clearing.
/caveman-help — quick-reference card. All modes, skills, commands, one command away.
/caveman:compress <filepath> — caveman make Claude speak with fewer tokens. Compress make Claude read fewer tokens.
Your CLAUDE.md loads on every session start. Caveman Compress rewrites memory files into caveman-speak so Claude reads less — without you losing the human-readable original.
/caveman:compress CLAUDE.md
CLAUDE.md ← compressed (Claude reads this every session — fewer tokens)
CLAUDE.original.md ← human-readable backup (you read and edit this)
| 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% |
Code blocks, URLs, file paths, commands, headings, dates, version numbers — anything technical passes through untouched. Only prose gets compressed. See the full caveman-compress README for details. Security note: Snyk flags this as High Risk due to subprocess/file patterns — it's a false positive.
Real token counts from the Claude API (reproduce it yourself):
| Task | Normal (tokens) | Caveman (tokens) | 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% |
Range: 22%–87% savings across prompts.
Important
Caveman only affects output tokens — thinking/reasoning tokens are untouched. Caveman no make brain smaller. Caveman make mouth smaller. Biggest win is readability and speed, cost savings are a bonus.
A March 2026 paper "Brevity Constraints Reverse Performance Hierarchies in Language Models" found that constraining large models to brief responses improved accuracy by 26 percentage points on certain benchmarks and completely reversed performance hierarchies. Verbose not always better. Sometimes less word = more correct.
Caveman not just claim 75%. Caveman prove it.
The evals/ directory has a three-arm eval harness that measures real token compression against a proper control — not just "verbose vs skill" but "terse vs skill". Because comparing caveman to verbose Claude conflate the skill with generic terseness. That cheating. Caveman not cheat.
# Run the eval (needs claude CLI)
uv run python evals/llm_run.py
# Read results (no API key, runs offline)
uv run --with tiktoken python evals/measure.pyIf caveman save you mass token, mass money — leave mass star. ⭐
Three tools. One philosophy: agent do more with less.
| Repo | What | One-liner |
|---|---|---|
| caveman (you are here) | Output compression skill | why use many token when few do trick — ~75% fewer output tokens across Claude Code, Cursor, Gemini, Codex |
| cavemem | Cross-agent persistent memory | why agent forget when agent can remember — compressed SQLite + MCP, local by default |
| cavekit | Spec-driven autonomous build loop | why agent guess when agent can know — natural language → kits → parallel build → verified |
They compose: cavekit orchestrates the build, caveman compresses what the agent says, cavemem compresses what the agent remembers. Install one, some, or all — each stands alone.
- Revu — local-first macOS study app with FSRS spaced repetition, decks, exams, and study guides. revu.cards
MIT — free like mass mammoth on open plain.