Caveman Prompt File
for GitHub Copilot

why install when copy do trick

I did not want to install the original caveman repository through NPM when I only needed a simple Markdown prompt file.

This repo keeps it simple: grab .github/prompts/caveman.prompt.md, drop it where your editor expects it, and use it.

---

Caveman's original description:

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( wenyan-mode), [...] 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. [...]

Credit goes to Julius Brussee and all contributors to the original project. This repo is only a lightweight guide and packaging of the prompt-file workflow. 🙌

⁉️ What is in repo

• .github/prompts/caveman.prompt.md
  • slash-command prompt for VS Code
• .github/prompts/caveman.instructions.md
  • always-on caveman mode
• README.md
  • setup guide

🧠 Quick answer

• VS Code: supports prompt files directly
• JetBrains and most other IDEs: copy prompt text into Copilot custom instructions instead

⏩ Fast start

1️⃣ Option 1: Use caveman globally in VS Code

Use this if you want /caveman in every workspace. It will download the required files to VS Code's global config directory at ~/.config/Code/User/prompts/.

Run from anywhere. Adjust the paths, if needed.

1. Download caveman prompt file:

$ curl -fsSL https://raw.githubusercontent.com/Mijutra/caveman-copilot/refs/heads/main/.github/prompts/caveman.prompt.md -o ~/.config/Code/User/prompts/caveman.prompt.md

Now /caveman works in every repository.

2. Optional: Download caveman instructions file for always-on mode:

$ curl -fsSL https://raw.githubusercontent.com/Mijutra/caveman-copilot/refs/heads/main/.github/prompts/caveman.instructions.md -o ~/.config/Code/User/prompts/caveman.instructions.md

On every new chat, caveman is automatically used in full mode.

2️⃣ Option 2: Download .github/ files into repo

See option 1 to use caveman globally.

Use this if you want direct copy without cloning repo. It will download the required files to your local repository's GitHub directory at ~/.github/prompts/.

1. Change directory to your repository root.

2. Create prompts directory:

$ mkdir -p .github/prompts

3. Download caveman prompt file:

$ curl -fsSL https://raw.githubusercontent.com/Mijutra/caveman-copilot/refs/heads/main/.github/prompts/caveman.prompt.md -o .github/prompts/caveman.prompt.md

Now /caveman works in every repository.

4. Optional: Download Copilot instructions for always-on mode:

$ curl -fsSL https://raw.githubusercontent.com/Mijutra/caveman-copilot/refs/heads/main/.github/prompts/caveman.instructions.md -o .github/prompts/caveman.instructions.md

On every new chat, caveman is automatically used in full mode.

3️⃣ Option 3: Clone repo

See option 1 to use caveman globally.

Use this if you want workspace prompt plus optional always-on mode.

1. Clone this repo:

git clone git@github.com:Mijutra/caveman-copilot.git

2. Copy .github/ dir into your repo root:

cp -r caveman-copilot/.github /path/to/your-repo/

Now /caveman works in every repository and on every new chat.

⁉️ How to use

ℹ️ Use /caveman only once at the begin of a new chat. No need to use it on every prompt!

Manual prompt is not needed, if you use the .github/prompts/caveman.instructions.md for always on mode, because it is used automatically on every new chat.

Manual prompt on every new chat:

/caveman

Adjust caveman levels of response:

/caveman lite
/caveman full
/caveman ultra

Turn off caveman:

normal mode

Prompt behavior:

• default level is full
• supports lite, full, ultra
• keeps technical meaning, cuts filler
• stops for current chat when you say stop caveman or normal mode

🔛 Always-on mode

Use .github/prompts/caveman.instructions.md for caveman on every new chat.

⚠️ Important:

• repo-wide, not global
• better than running /caveman every new chat

⛔ If always-on mode not needed:

• remove caveman.instructions.md
  • Local: .github/prompts/caveman.instructions.md
  • User Data: ~/.config/Code/User/prompts/caveman.instructions.md
• keep using /caveman manually

💻 IDE notes

VS Code

• prompt files belong in .github/prompts for workspace scope or in ~/.config/Code/User/prompts for global scope
• user prompts also work through Chat Customizations
• if you open only subfolder, parent customization discovery may matter

JetBrains

JetBrains supports Copilot custom instructions better than VS Code-style prompt files.

Best path:

1. Open .github/prompts/caveman.prompt.md.
2. Copy prompt body.
3. Paste into GitHub Copilot custom instructions.
4. Save.

If you want repo-level reuse, keep adapted text in .github/prompts/caveman.instructions.md.

Other tools

Works directly as prompt file:

• VS Code

Usually needs custom instructions:

• JetBrains IDEs
• Visual Studio
• Eclipse
• Xcode
• Copilot CLI
• GitHub.com / web Copilot

Safe cross-IDE pattern:

1. Keep .github/prompts/caveman.prompt.md as source of truth.
2. Mirror behavior into .github/prompts/caveman.instructions.md when tool supports repo instructions.
3. Use personal Copilot instructions when repo-level instructions do not fit.

⚙️ Why repo exists

Upstream project good. For GitHub Copilot prompt-file workflow, many people only need one Markdown file, not full package install.

This repo keeps path small:

• no package install
• no runtime setup
• prompt file ready
• repo instructions optional

🎥 Credits

Full credit for idea, prompt design, and original project goes to Julius Brussee and contributors behind caveman.