Setup

Setting up Claude Cowork

This page walks you through the Claude Desktop UI as it exists today and then runs the Trelleborg scaffold skill inside Cowork to build your starter folder. There is no separate command-line tool and nothing to install beyond Claude Desktop itself.

§1 — Before you begin

Before you begin

§2 — The walkthrough

The walkthrough

The labels below match what you see on screen. If the wording in your version differs, the labels in Anthropic's support article are the source of truth.

  1. Open Claude Desktop. Sign in if prompted. Wait for the main window to finish loading. The first time you open the app after installing, Claude runs a Cowork readiness check — a one-off verification that your machine can host the Cowork virtual machine. Click through any prompts.
  2. Click the “Cowork” tab in the left sidebar. If you do not see it, your plan does not yet include Cowork — check your subscription tier under Settings > Account or speak to your Trelleborg admin.
  3. Open Customize and confirm the starter skill is listed. From the Cowork chat surface, open Settings > Customize. Under Skills you should see trelleborg-cowork-starter. If not, your IT contact needs to publish it to your account.
  4. Choose “Use existing folder” when prompted to pick a project type. Paste or drag in the path to the empty folder you prepared in §1.
  5. Pick a mount mode. Cowork lets you choose how much it can do with the folder. See §3 below — for the pilot, start with Read-write, no delete.
  6. Run the starter skill. In the Cowork chat box, type /trelleborg-cowork-starter and press enter. The skill asks four short questions (your name, your role in one line, communication style, whether to pre-populate any examples), then writes the folder for you. No restart needed.
  7. Paste your INSTRUCTIONS.md into the Instructions field for this project. The starter skill prints the path; open the file in the Cowork file view, copy its contents, and paste them into Project settings > Instructions. You only do this once.
  8. Describe your first task. Try something small — “summarise the three files in context/ back to me in your own words.” Cowork shows its plan before touching any file. Read the plan, confirm, watch it work.
“Ask before acting” vs “Act without asking”. When you confirm a plan, you also pick the permission mode for that session. For your first few projects, leave it on Ask before acting — Cowork pauses before each file write so you can stop a session that has gone off-track.
§3 — Folder permissions

Choosing a mount mode

When you connect a folder, Cowork asks how much it can do with it. The three modes trade off speed for safety. You can change this later from project settings.

Mode What Cowork can do When to pick it
Read-only Read every file in the folder; write nothing back. Reviewing a folder you do not want changed — auditing a colleague's archive, or letting Cowork answer questions about a research collection.
Read-write, no delete Recommended for first project Read, edit, and create files. Cowork still asks you before permanently deleting anything. Standard personal-assistant use. Safe default — the worst-case is a confused edit, not a vanished file.
Read-write Full file-system access inside the folder, including deletes. Mature workflows where you have run the same task successfully several times. Pair with the manual-backup habit on the Safety page.
Mount modes apply at the folder level, not per file. You cannot say “Cowork may delete files in output/ but not elsewhere.” If you need that granularity, create a second Cowork project pointed at a subfolder.
§4 — After your first run

After your first run

  1. Open the folder in Finder. Look at what Cowork wrote. The output/ subfolder is where finished work lands; each file is date-prefixed. If something looks wrong, you see it before it propagates.
  2. Read the session summary Cowork posts in its own UI. It lists every file it touched. Treat this like a code review — quick scan, then move on if everything looks reasonable.
  3. Glance at MEMORY.md. Cowork will start adding short, dated entries here as it learns about you. One or two sentences each. The Memory & Scheduling page explains the 150-line cap and the ARCHIVE.md overflow.
  4. Update context/current-focus.md if your priorities for the week have shifted. This is the one file you will edit most often. Keep it short — the cap is 300 words.
Next — Folder shape & INSTRUCTIONS template → Memory & scheduling →