grug-brain

grug brain skill for AI assistants. make AI write simpler code. fight complexity demon.

inspired by grugbrain.dev. go read, grug learn lot there.

what this do

when AI use this skill, AI become grug. grug hate complexity. grug like simple.

grug will:

• tell you if code too complex
• suggest simpler way
• explain things in grug speak
• review code and find complexity demon

how use with different ai

skill file is SKILL.md. copy whole folder, not just file.

github copilot (vs code)

copilot have skill system! grug happy. very easy.

personal (work in all projects):

~/.copilot/skills/grug-brain/SKILL.md

project only:

.github/skills/grug-brain/SKILL.md

then in chat: /grug-brain or just ask. copilot load skill automatic.

claude code (cli)

claude code also have skill system! use same SKILL.md format.

personal:

~/.claude/skills/grug-brain/SKILL.md

project only:

.claude/skills/grug-brain/SKILL.md

then in chat: /grug-brain or describe task, claude load it.

opencode

opencode have skill system. grug happy.

personal:

~/.agents/skills/grug-brain/SKILL.md

project only:

.agents/skills/grug-brain/SKILL.md

tell opencode: "use grug-brain skill" or type /grug-brain.

cursor ai

cursor use rules system.

1. create .cursor/rules/grug-brain.mdc in project root
2. paste SKILL.md content (skip yaml frontmatter, just body)
3. set rule type to "always" or "agent requested"
4. cursor now grug-brain enabled

claude.ai (web)

project instructions:

1. open project settings
2. paste SKILL.md content into custom instructions
3. grug always active for that project

one-off:

1. paste SKILL.md content at start of chat
2. say: "follow these instructions"
3. grug brain activate

chatgpt / others

if AI let you add system prompt or custom instructions:

1. copy SKILL.md body (skip yaml frontmatter)
2. add to custom instructions or system prompt
3. ask AI to "follow grug philosophy"
4. simple!

example prompts

use these to activate grug brain:

• "review this code with grug-brain skill"
• "think like grug - is this too complex?"
• "grug refactor this code"
• "explain this bug in grug speak"
• "would grug write it this way?"

when use grug

good times for grug:

• code review
• architecture decision
• refactoring
• debugging
• learning new code

bad times for grug:

• writing poetry (grug bad at poetry)
• writing love letters (grug not romantic)
• writing academic papers (grug not academic)

what grug believe

• best feature: feature not built
• best abstraction: abstraction not added
• complexity: apex predator
• simple: always better than clever

if grug say "no", listen. grug wise.

contribute

want make grug better? good.

keep it simple. no complex build steps. no complex dependencies.

just markdown file. simple.

license

grug not care about legal. do what you want. just fight complexity.

thanks

big thanks to grugbrain.dev - the original grug who teach grug everything.

grug just messenger.

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remember: given choice between complexity or one on one against t-rex, grug take t-rex. at least grug see t-rex.