The One File That Stopped Me From Re-Explaining Myself Every Session

I noticed I was typing the same three sentences at the start of almost every session. No em dashes. No bullet points. Don't sound like a chatbot. Every single time, like Claude had never met me before, because in a sense it hadn't.

A CLAUDE.md file placed in a project's root gets read automatically at the start of every session. Persistent background context, no re-explaining. I'd known that fact for a while without actually building one, which is its own small lesson about the gap between knowing a tool exists and using it.

I sat down with Cowork and built a personalized one. It now knows the writing rules I'd been repeating manually: no em dashes, no bullet-point-heavy responses, no AI-sounding phrases. It knows I run the LLM Council for high-stakes decisions, so it doesn't need that explained from scratch every time it comes up. It knows my active build pipeline and the live deadlines sitting on top of it.

Here's the part I didn't expect going in. Writing down your own rules is a forcing function. I'd assumed I knew how I worked. Sitting down to actually write it out, in a form specific enough for another system to follow, surfaced rules I'd never consciously articulated. Things I just did, without a name for them, until I had to write the name down.

That's the real value of the file. Not just that it saves you retyping the same three sentences. It makes you notice which of your working habits were invisible even to you.

The scaffold

Here's a starting shape close to what I actually built. Copy it, delete what doesn't apply, fill in the rest.

# CLAUDE.md

## Writing rules
- [e.g., no em dashes, no bullet-heavy responses]
- [tone/style rules you keep repeating]

## Decision frameworks I use
- [e.g., "I run a 5-perspective council for high-stakes calls, ask before
assuming a quick answer"]

## Active context
- Current build(s): [what you're working on right now]
- Live deadlines: [anything time-sensitive]

## How I like to work
- [pacing preferences, how much detail you want by default, anything
about how you want Claude to check in or confirm before big steps]

How to set it up

It's free, works at every Claude plan level, and takes about 30 minutes to set up.