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

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 (MIT license, Copyright (c) 2026 Julius Brussee). This SKILL.md is an original specification authored for hve-core; no upstream files are redistributed.