caveman
Caveman is a prompt-engineering skill/plugin for Claude Code and 30+ other AI agents that reduces output tokens by ~65% by constraining agent responses to concise, stripped-down language while preserving technical accuracy. Install once, and every agent reply becomes shorter and faster without loss of information.
Key facts
Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.
| Field | Value |
|---|---|
| Repository | JuliusBrussee/caveman |
| Owner | JuliusBrussee |
| Primary language | JavaScript |
| License | MIT — OSI-approved |
| Stars | 86.3k |
| Forks | 4.8k |
| Open issues | 370 |
| Latest release | v1.9.1 (2026-07-03) |
| Last updated | 2026-07-03 |
| Source | https://github.com/JuliusBrussee/caveman |
What caveman is
A JavaScript-based plugin that injects brevity constraints into agent prompts across multiple agent platforms (Claude Code, Cursor, Windsurf, Cline, Copilot, Gemini, and others). Offers six compression levels (lite, full, ultra, wenyan, etc.) and ancillary commands for commits, reviews, and file compression. Benchmarks show 65% avg output-token reduction; input tokens and reasoning tokens are unaffected.
Get the caveman source
Clone the repository and explore it locally.
git clone https://github.com/JuliusBrussee/caveman.gitcd caveman# follow the project's README for install & configurationNeed it deployed, integrated, or customized instead? DEV.co ships production installs.
Best use cases
Implementation considerations
- Installation is one-liner (bash/powershell) and auto-discovers agents on the system; requires Node ≥18. Safe to re-run and includes per-agent install matrix in INSTALL.md.
- Six compression levels (lite, full, ultra, wenyan) can be toggled per session with `/caveman [level]` command. Default is 'full'; wenyan mode outputs classical Chinese for maximum token compression.
- Preserves code, commands, error messages, and URLs byte-for-byte; only compresses natural-language prose. Technical accuracy claimed at 100% but no independent audit provided.
- Ancillary features: `/caveman-commit` (short commit messages), `/caveman-review` (one-line PR comments), `/caveman-compress` (rewrite memory files), and cavecrew subagents for investigation/building/review.
- Output-only compression; reasoning tokens and input tokens are unaffected. Whole-session ROI depends on baseline verbosity and session length. Recommend profiling with `/caveman-stats` before/after.
When to avoid it — and what to weigh
- You need verbose, educational explanations — Caveman strips filler and preamble—good for experienced engineers, poor for mentoring or learning-focused interactions. Mode can be toggled per session, but default is terse.
- Your workload is already token-efficient — Skill adds ~1–1.5k input tokens per turn. On already-terse replies or short sessions, whole-session savings can go net-negative. Honest-numbers doc recommends measuring your own baseline.
- You require formal, compliance-grade communication — Caveman-speak is informal and playful by design. Not suitable for customer-facing docs, regulatory reports, or formal RFP responses.
- Your agent does not support custom plugins or rules — Installation requires agent-specific setup (plugin marketplace, extension registry, or npx skills). Older or proprietary agents not on the 30+ supported list will not work.
License & commercial use
MIT License. Permissive open-source; allows commercial use, modification, and distribution with attribution and no warranty.
MIT is a standard OSI-approved permissive license. Commercial use, resale, and bundling are allowed. No additional licensing concerns flagged in data. Caveman itself is open-source; consuming or modifying it carries no known commercial restrictions. Confirm your agent's licensing model separately (e.g., Cursor, Windsurf license terms).
DEV.co evaluation signals
Editorial assessment — not user reviews. Directional, with an explicit confidence level.
| Signal | Assessment |
|---|---|
| Maintenance | Active |
| Documentation | Strong |
| License clarity | Clear |
| Deployment complexity | Low |
| DEV.co fit | Strong |
| Assessment confidence | High |
Caveman modifies agent prompts and responses locally. No server communication or external APIs invoked (install script pulls from GitHub, but runs locally). Injected system prompts should be reviewed by your security team before deployment. No CVE data, penetration test results, or formal security audit mentioned. Recommend code review of install.sh and plugin logic before enterprise rollout.
Alternatives to consider
Manual prompt engineering / system prompt tuning
DIY approach: write your own brevity rules or few-shot examples. No plugin overhead, full control. Requires time investment per agent and may not generalize across platforms.
Agent-native features (e.g., Claude 3.5 Sonnet's built-in concision)
Some models have native brevity modes or shorter-output training. No plugin needed; verify with your model's docs. May be less customizable than Caveman's six levels.
Token budget / max_tokens API parameter
Crude but effective: cap agent output length at the API level. Forces brevity without style change. Works for all agents; no install needed. May produce truncated/incomplete answers.
Build on caveman with DEV.co software developers
Install Caveman in 30 seconds. Works with Claude Code, Cursor, Windsurf, and 30+ other agents. Start saving output tokens—and money—on every reply.
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caveman FAQ
Does Caveman reduce input tokens or reasoning tokens?
Can I toggle Caveman on/off mid-session?
Does Caveman work with my agent/IDE?
Is the 65% token savings number real?
Software developers & web developers for hire
DEV.co is a software development agency delivering custom software development services to companies building on open source. Our software developers and web developers design, integrate, and ship production systems — spanning web development, APIs, AI, data, and cloud. If caveman is part of your ai frameworks roadmap, our team can implement, customize, migrate, and maintain it.
Ready to Cut Your Agent Costs?
Install Caveman in 30 seconds. Works with Claude Code, Cursor, Windsurf, and 30+ other agents. Start saving output tokens—and money—on every reply.