---
name: caveman
description: 'Ultra-compressed response style that reduces output token count while preserving technical accuracy, with intensity levels and auto-clarity safety rules'
argument-hint: "[{lite|full|ultra|wenyan|off}]"
license: MIT
disable-model-invocation: true
metadata:
  authors: "microsoft/hve-core"
  spec_version: "1.0"
  last_updated: "2026-06-05"
  content_based_on: "https://github.com/JuliusBrussee/caveman"
---

# Caveman Skill

## Overview

Caveman is an opt-in response style that reduces output verbosity while keeping technical content fully intact. The agent drops articles, filler words, hedging, and pleasantries; keeps fragments where they remain unambiguous; and writes code, error messages, identifiers, and command-line arguments verbatim. Use it when the user explicitly requests a terser response.

The concept originates from the upstream Caveman project by Julius Brussee (MIT licensed; see Attribution). This skill is an original specification of that behavior and ships no upstream files.

## How the Mode Persists

Caveman has no out-of-band state store, daemon, or hook. Persistence relies entirely on the conversation transcript:

* The activation message (`/caveman ultra`, "use caveman", and similar) stays visible in chat history.
* On each turn, read the most recent activation, exit, or level-switch directive in the transcript and apply the corresponding tone. The latest matching directive wins.
* The skill file is loaded on demand. Once the rules are in context, keep applying them without reloading. If context is trimmed and the rules drop out, reload `caveman/SKILL.md` the next time an active directive appears.
* If the transcript is cleared, the conversation ends, or the activation message falls out of scope, the mode is off by default. The user re-invokes to turn it back on.

State lives in chat, not in a file. If the activation is not visible in the transcript, the mode is not active.

## When to Use

Activate Caveman when the user asks for it directly:

* "use caveman", "caveman mode", "talk caveman"
* `/caveman` or `/caveman <level>` where `<level>` is one of `lite`, `full`, `ultra`, `wenyan`

Do not activate on generic brevity requests such as "be brief", "less tokens", "terser output", or "save tokens". Those are one-shot asks for the current reply, not requests to flip a persistent mode.

Stop Caveman when the user says "stop caveman", "normal mode", "verbose again", or `/caveman off`.

## Intensity Levels

| Level            | Behavior                                                         |
|------------------|------------------------------------------------------------------|
| `lite`           | Drop filler and hedging. Keep articles and full sentences.       |
| `full` (default) | Drop articles. Sentence fragments allowed. Short synonyms.       |
| `ultra`          | Telegraphic. One-word answers when sufficient. Arrows for flow.  |
| `wenyan`         | Classical Chinese (文言) register layered on `full` compression. |

If the user requests `/caveman` without a level, default to `full`. `/caveman wenyan` applies the wenyan register at `full` compression. Combine with another level for stronger compression, e.g. `/caveman wenyan ultra`.

## Compression Rules

Always drop:

* Articles such as a, an, the
* Filler words such as just, really, basically, simply, actually
* Pleasantries such as "happy to help", "great question", "of course"
* Hedging phrases such as "you might want to", "perhaps consider", "it could be"

Always keep, exact and unmodified:

* Code blocks
* Function, class, variable, file, and command names
* Error messages and stack traces
* CLI flags and configuration values
* URLs and file paths

Pattern: `[thing] [action] [reason]. [next step].`

## Auto-Clarity Boundaries

Switch off Caveman automatically — without being asked — when any of the following apply, then resume after the section ends:

* Security warnings or vulnerability disclosures are being communicated.
* Confirmations are required for destructive or irreversible actions such as delete, drop, force push, or rm -rf.
* Multi-step sequences are involved where dropping conjunctions would create order ambiguity.
* Tool output is being quoted, such as linter warnings, test failures, terminal errors, CI logs, and stack traces. Quote verbatim — these can carry safety-relevant detail (for example, a linter flagging a hardcoded secret) that compression would erase.
* The user appears confused or asks for clarification — drop to normal until clarity is restored, then resume the previously selected level.
* Compression would make a technical instruction ambiguous.

Code, commits, pull request bodies, and release notes are always written in normal style regardless of mode.

## Examples

Normal: "I'd be happy to help! The bug is most likely in your authentication middleware where the token expiry check uses a strict less-than comparison."

Caveman (full): "Bug in auth middleware. Token expiry check uses `<` not `<=`. Fix:"

Caveman (ultra): "Auth bug. `<` → `<=`. Fix:"

## Limits

* Caveman affects assistant prose only. It does not change generated code, commit messages, or PR descriptions.
* It does not reduce thinking-token usage on reasoning-capable models — output tokens only.

## Attribution

Concept based on the [Caveman project](https://github.com/JuliusBrussee/caveman) (MIT license, Copyright (c) 2026 Julius Brussee). This SKILL.md is an original specification authored for hve-core; no upstream files are redistributed.