caveman is a skill and proxy for coding agents that shortens unnecessary explanatory prose so agents use fewer tokens while leaving code, commands, paths, and error messages unchanged. It is for people using coding agents who want terse responses and lower token use, including with Claude-based workflows. The catalogue entries contain its skills, commands, agents, instructions, and plugins.
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.
npx skills add JuliusBrussee/caveman --skill caveman-helpgit clone --depth 1 https://github.com/JuliusBrussee/cavemanWrote 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.
[](https://agentmods.dev/skills/juliusbrussee/caveman/caveman-help)<a href="https://agentmods.dev/skills/juliusbrussee/caveman/caveman-help"><img src="https://agentmods.dev/badge/skills/juliusbrussee/caveman/caveman-help/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.
<a href="https://agentmods.dev/skills/juliusbrussee/caveman/caveman-help"><img src="https://agentmods.dev/badge/skills/juliusbrussee/caveman/caveman-help.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Rogue Agent · line 40 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00032 | $0.00708 |
| Opus 5.5 | $0.00013 | $0.00283 |
| Sonnet 5.5 | $0.00006 | $0.00142 |
| Haiku 4.5 | $0.00003 | $0.00071 |
Grade A, and why
caveman-help 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 16d 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.
Copies of this mod
8 near-identical copies found in the catalogue:
- caveman-help — 91% identical, 28 lines differ
- caveman-help — 88% identical, 31 lines differ
- caveman-help — 88% identical, 31 lines differ
- caveman-help — 88% identical, 31 lines differ
- caveman-help — 88% identical, 32 lines differ
- caveman-help — 88% identical, 31 lines differ
- caveman-help — 88% identical, 30 lines differ
- caveman-help — 88% identical, 31 lines differ
How it starts
The opening of the file, as written. The whole thing — 63 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Caveman Help
Display this reference card when invoked. One-shot — do NOT change mode, write flag files, or persist anything. Output in caveman style.
Modes
| Mode | Trigger | What change |
|---|---|---|
| caveman | /caveman |
The voice. Answer first, no fluff, every fact kept. Default. |
| ultracave | /ultracave (alias /caveman ultra) |
Grammar stripped. Fragments, one word when enough, each fact once. |
| megacave | /megacave (alias /caveman wenyan) |
Classical Chinese 文言文. Far fewer characters, technical terms verbatim. |
Mode stick until changed or session end.
/caveman status reports current mode without changing it. Claude Code and the standalone OpenCode plugin read stored state; other hosts answer from the conversation and mark it (not tracked by this host).
Skills
| Skill | Trigger | What it do |
|---|---|---|
| caveman-commit | /caveman-commit |
Terse commit messages. Conventional Commits. ≤50 char subject. |
| caveman-review | /caveman-review |
One-line PR comments: L42: bug: user null. Add guard. |
| caveman-compress | /caveman-compress <file> |
Compress .md files to caveman prose. 33.2% fewer tokens on the repo's five test files. |
| caveman-help | /caveman-help |
This card. |
Deactivate
Say "stop caveman" or "normal mode". Resume anytime with /caveman.
Language
Keep user's language by default — reply in the language user writes, never switch regardless of example text or multilingual context elsewhere. Compress the style, not the language. Technical terms, code, commands, commit types, and exact error strings stay verbatim unless user ask for translation.
Configure Default Mode
Default mode = caveman. Change it:
Environment variable (highest priority):
export CAVEMAN_DEFAULT_MODE=ultracave
Config file (~/.config/caveman/config.json):
{ "defaultMode": "ultracave" }
For opt-in activation in Claude Code, set defaultMode to manual. Sessions start off; /caveman or talk like caveman activates caveman. off also disables bare-command activation. manual is a startup policy, not a mode. OpenCode still starts in caveman mode because its installer also supplies static activation rules.
What ships with it
1 file 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.
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.
- 16d ago Changed 0bf9ee3fc8a9
- 22d ago Changed · +1 tokens per session 150dc9b454d6
- 1mo ago Changed 3effbc5b8943
- 1mo ago First seen · 63 lines · 31 tokens per session scan A e704f9504ebe
caveman-help is a skill published in the GitHub repository JuliusBrussee/caveman (114,861 stars, last pushed today), licensed Apache-2.0. It adds 32 tokens to every session and 708 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-08-30.
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