Per-folder instructions for Claude and ChatGPT
Custom AI instructions,
per folder.
Different folders, different rules. Claude and ChatGPT read your folder-level instructions every time they touch a note. Tell them your conventions once. Stop re-explaining yourself.
Free to start. No credit card required.
The problem with one global setting
One AI. Many kinds of work.
ChatGPT's Custom Instructions are one global box. Claude's system prompt is one global box. Both treat your whole life as a single project.
But you don't work that way. Your runbooks need step-by-step format. Your customer interviews need the quote up front. Your recipes need metric units. Cramming all of that into one prompt makes none of it work well.
Hjarni puts the rules where the content is. Each folder has its own.
Inheritance, in pictures
Rules stack on the way down.
Open a note deep in the tree. Claude and ChatGPT read every rule on the way to it.
Your folders
-
Personal
"Prefer bullets. Lowercase titles."
-
Projects
"Tag with project name. Link related notes."
-
React
"TypeScript code blocks. Cite the React docs."
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Bugs you open a note here
"Always include reproduction steps and severity."
What Claude and ChatGPT see
Prefer bullets. Lowercase titles.
Tag with project name. Link related notes.
TypeScript code blocks. Cite the React docs.
Always include reproduction steps and severity.
Hjarni hands all four to whichever AI opens the note. No prompt engineering. No copy-paste.
Works with both
Claude and ChatGPT. Same rules.
Hjarni's MCP server hands your folder instructions to whichever AI is reading the note. No vendor lock-in. No copy-paste between tools.
What it isn't
Not the same as Custom Instructions or Projects.
ChatGPT Custom Instructions
One global box. ChatGPT only. Same rules whether you're writing recipes or shipping production code.
Claude Projects
One system prompt per project. Flat. No folder hierarchy. No inheritance. Claude only. Your ChatGPT doesn't see it. Compare Hjarni vs Claude Projects.
Notion AI / Obsidian Copilot
Bolted-on AI. No instruction system. No way to tell the AI how to behave inside a specific folder.
Hjarni
Instructions at every folder, with inheritance. Team-wide rules for shared conventions. Same rules apply whether you're in Claude, ChatGPT, or any other MCP client.
From a founder
Hjarni ran the whole Labeur launch. Scope decisions, landing page copy, App Store submission, launch day checklist, all in one place and all in sync with Claude. I stopped re-explaining myself to the AI. From first sketch to live in the store.
Tell your AI your rules. Once.
Set up your first folder instructions in two minutes. Free to start.
Free to start. No credit card required.