Cowork is the agentic mode inside Claude Desktop. You describe an outcome, step away, and come back to finished work — written directly to a folder on your computer. This guide gets you from zero to a working personal-assistant workspace in about fifteen minutes. Written for Trelleborg colleagues who do not consider themselves technical.
Each frame below corresponds to one screen you will see. Everything happens inside Claude Desktop — there is no separate command-line tool to install. Step-by-step instructions live on the Setup page; this is the bird's-eye view.
Launch the desktop app and click Cowork in the left sidebar. If you do not see it, update to the latest version — Cowork went generally available in April 2026.
Click Use existing folder and pick a fresh, dedicated folder — never your Documents root, your Desktop, or iCloud Drive root.
In the Cowork chat box, type
/trelleborg-cowork-starter. The skill runs inside
Cowork itself — no terminal required. It asks four short
questions, then writes your INSTRUCTIONS.md,
MEMORY.md, and the supporting folder shape.
Open INSTRUCTIONS.md from the file view, copy its
contents, paste them into Cowork's
Instructions field for this project. Then
describe your first outcome in chat. Done.
The starter skill writes this on your behalf. You do not need to understand every file before your first task — but glance at the shape so it is not a surprise.
my-cowork/ ├── INSTRUCTIONS.md # Pasted into Cowork's field 200–300 lines ├── MEMORY.md # Running notes Claude maintains 150 lines ├── ARCHIVE.md # Overflow when MEMORY.md fills ├── context/ # Detail Claude reads on demand │ ├── about-me.md │ ├── work-preferences.md │ └── current-focus.md ├── inbox/ # Quarantine for anything you did not write ├── projects/ # One subfolder per active project ├── reference/ # Long-form material — read on demand only ├── output/ # Where Claude writes finished work ├── daily-notes/ # One file per day └── archive/ # Completed work, moved by you
The two files at the top — INSTRUCTIONS.md and
MEMORY.md — are where most of the discipline
lives. Both have explicit size caps, borrowed from the pattern
Jeff Su's team formalised in May 2026 after measuring a ~25%
drop in tokens-per-session when their root files were cut to
size.
The remainder of the folder is a quarantine-and-output system:
inbox/ for anything that arrived from outside,
projects/ for active work, output/ for
what Claude produces, and archive/ for completed
material. Each named so that — three months from now —
the folder still makes sense.
Anthropic's product line uses similar words for very different things. Read this once and the rest of the guide will make sense.
| If you mean… | It actually is… | How it differs from Cowork |
|---|---|---|
| claude.ai Projects | Cloud-based conversation folders on the claude.ai website | Cloud-synced, chat-based, no agentic execution, no local file access |
| Claude Code | Developer command-line tool for agentic coding | Lives in a terminal, code-first, no desktop GUI. Cowork is the Claude Desktop equivalent for knowledge workers. |
| Teams (the plan) | A pricing tier | A billing level, not a feature. Cowork runs on the Team plan, among others |
| Workspaces (Console) | API-level organisation units in the Anthropic developer console | For developers managing API keys and billing — unrelated to desktop Cowork |
| Skills | Packaged capabilities you can install into Claude | The Trelleborg starter is a skill. Skills extend Cowork's capabilities; they are not the workspace itself. |
| Plugins | Bundles of skills and connectors for role-specific use | Adds capability to Cowork, not the container. Managed under Customize in the desktop app. |
Anthropic has not yet published an official personal-assistant Cowork tutorial. The community videos below are the strongest starting points. Tina Huang's May 2026 follow-up is the most accessible introduction; Jeff Su's piece is the closest match to the model this guide adopts.
INSTRUCTIONS/MEMORY/ARCHIVE
discipline, Ruben Hassid's revised text-file approach, and the
quarantine pattern that has stabilised across the community.
INSTRUCTIONS.md,
MEMORY.md, ARCHIVE.md) are not a
surprise the first time you open them.
context/:
who you are, how you like to work, what you are focused on this
week. Total about half a page of writing.
inbox/ — and let
Cowork plan it. Review the plan, confirm, and watch it work.
Cowork can read and modify everything in the folder you connect to it. That makes the choice of which folder you connect a security decision. There is one documented attack class and a short list of rules to follow — none of which require any technical skill.
How the PromptArmor attack worked, the three folders to never connect, and the manual backup that costs ten seconds. Read once before you connect a folder that already contains real files.