Claude Desktop course
Lesson 6 of 7

Lesson 6 · about 25 minutes

Hand a longer task to Cowork

By the end, you've given Cowork a job with several steps on a folder of files, watched it work, approved what it needed approved, and checked the result against a known answer. You'll also know which files it can reach and what it asks before it acts.

From lesson 4
Where do you add a tool that isn't in the connector list but gives you a connector URL?

In Customize › Connectors, as a custom connector: click + Add, then Add custom connector, and paste the address. On Team and Enterprise only an Owner adds it, in Organization settings › Connectors. Cowork can use your connectors too, the links to your mail, calendar and files.

ThinkDelegation

What would you hand over, and what does done look like?

A chat answers one question. Cowork takes a job: it makes a plan, works through the files and comes back with a result. Pick a job it can finish and you can check.

In lesson 1 you picked a first task:

It should have several steps, work on a set of files in one folder, and end in something you can check. For example, checking supplier invoices against deliveries, or turning a folder of meeting notes into one summary. Using the practice folder? Write "Check the Northgate invoices against goods received".

Name the result (a spreadsheet, a short report, a renamed set of files) and where it should be saved. Then name anything that has to stay exactly as it is: the originals, a signed contract, last year's folder.

PredictDiligence

What can Cowork reach, and what does it ask first?

Guess before you give it any files.

You give Cowork a folder called Invoices. Your Documents folder sits right next to it. Can Cowork read or change files in Documents?
Show the answer

Only the folder you gave it. Anthropic says Claude can read and write files on your computer only in folders you've connected, and it can delete them there too. The folder limits files only: Claude can still browse the web and use your connectors.

On Pro, Max and Ultra, a task runs on Anthropic's servers (their computers, not yours), and files it opens are processed there. On Team and Enterprise an Owner setting, Run Cowork in the cloud, decides. It starts on for Team. On Enterprise it starts off, and tasks run on your own computer. Either way Claude reads the folder, so keep sensitive files out of it.

Halfway through a job, Cowork decides some old files should be deleted. What happens?
Show the answer

It stops and asks. Before Cowork deletes a file for good, it shows a permission prompt and waits until you select Allow. Anthropic says this applies in every mode.

Anthropic doesn't promise the same prompt before Claude overwrites or renames a file. So work on a copy of the folder (step 1), and run the first time in Manual mode, where Claude asks before it acts (step 4).

Do

Hand over the job

Six steps. Tick each one when it's done.

Claude Cowork Asks before deleting files for good YOUR COMPUTER northgate-march-invoices The copy you connected 4 invoices (PDF) goods-received.csv README.txt mismatches.xlsx new, made by Cowork Documentsnot connected Downloadsnot connected Desktopnot connected
What you're setting upCowork works inside the one folder you connect and saves its result there. Your other folders stay out of reach. Connectors and the web still work.

  1. Make a copy of the folder.

    Copy the folder that holds the files for your job and give Claude the copy, so your originals stay safe. Take out anything sensitive, like passwords or personal records, because Claude reads whatever is in the folder.

    Or use the practice folder

    Northgate Cycles is a made-up bike shop in Ellisford, Texas. The folder holds four supplier invoices from March 2026 and goods-received.csv, a plain table of deliveries that opens in Excel. Download the ZIP (one file that holds the folder), unzip it (on Windows, right-click it and choose Extract All) and use the folder inside as your copy.

    Download the ZIP (125 KB)

  2. Open a new task in Claude Desktop.

    If the message box shows Chat and Cowork, select Cowork in the bottom left corner. If it doesn't, there's nothing to select: any new conversation can take the task.

  3. Connect the copy.

    Under the message box, click Add folder and choose your copy. In some versions the button says Work in a project or folder. Pick the folder for this one job, not your whole Documents folder.

    Every folder Claude may use is listed under Trusted folders in Settings. Check that only this one is there.

  4. Set the mode to Manual.

    In the message box, open the permission menu. It shows the current mode, such as Auto. Choose Manual (older versions call it Ask before acting). In Manual, Claude stops before it acts and waits for you to select Allow or Deny.

    Auto keeps working and runs a safety check before each action. Skip drops the pauses and the checks. On Enterprise plans Manual is the default.

  5. Describe the job and send it.

    Say what you want to end up with, the format, and which files to work from. Copy this, replace each part in [square brackets] with your own words (delete the brackets too), and send it:

    Work in this folder only. [Describe the job in one sentence and name the files it covers.] When you're done, save the result as a new [file type] called [name] in this folder. Don't change, move or delete any existing file. Show me your plan first. If something is unclear, ask me instead of guessing.

    Using the practice folder? Copy this version

    Work in this folder only. It holds four supplier invoices (PDF) for the week of March 9, 2026, and goods-received.csv, which lists what was counted into our stock room. Check every invoice line: does the quantity match goods-received.csv, and is the line total right (quantity times unit price)? List every mismatch in a new spreadsheet called mismatches.xlsx, with these columns: invoice number, supplier, line, what the invoice says, what it should say, and the difference in dollars. Don't change, move or delete any existing file. Show me your plan first. If something is unclear, ask me instead of guessing.

  6. Read the plan, then let it run.

    Claude first replies with its plan, a short list of what it will do. If the plan mentions files outside your folder or deleting anything, reply "Stay in this folder and don't delete anything." If it looks right, reply "Go ahead" and let it work. Tick this step once the Check below passes.

    While it works, answer its questions and its Allow or Deny requests. If it opens files or sites you didn't mention, stop the task.

If you see this instead

There's no Cowork option, or it's greyed out
Cowork isn't on the Free plan, and on Team and Enterprise an Owner can turn it off in Organization settings › Cowork. Otherwise update Claude Desktop. No Cowork option after that means the newer layout, where any conversation takes tasks.
Claude says it can't open the files, or the task stalls
Tasks that use files on your computer need the Claude Desktop app open and online. Wake the computer, reopen the app, and check that the folder is under Trusted folders in Settings.
Claude asks for permission to delete or replace something you didn't expect
Select Deny and ask why. Check that your prompt said to leave existing files alone. If it keeps going outside what you asked, stop the task.
The result file isn't where you expected
Open the task and read where Claude says it saved the file. Finished files also show in the task, where you can preview and download them. Then look under Storage folder in Settings.
You hit your usage limit quickly
Multi-step tasks use more of your plan than a quick question. Group related work into one task, start a fresh conversation for unrelated work, and check Settings › Usage.
CheckDiscernment

Is the result right, and did the originals survive?

A finished task can still be wrong. Test it against the files yourself.

1 · PLAN Plan 1 Read every invoice 2 Match lines to the CSV 3 Write mismatches.xlsx 4 Ask me if unsure You read the plan before it starts 2 · WORK HTT-26-3307.pdf MOS-2026-10418.pdf LWS-26-0457.pdf MOS-2026-10463.pdf Progress shows as it works. It may ask you a question. 3 · RESULT mismatches.xlsx Invoice · Line · Problem A new file in your folder. You check it.
How a handed-over task runsPlan, work, then a result file you check.

With your own task

Open the result and pick three items. For each, find the same item in its source file and compare, with a calculator for any sums. You pass when the result is in the format you asked for and all three agree.

You also pass only if nothing else changed. In the folder Claude worked in, every file but the new one should keep its name and its Date modified (list view on a Mac, Details view on Windows). To double-check, ask Claude to list every file it created, changed, renamed or deleted.

With the practice folder

You pass when mismatches.xlsx lists the two mismatches in the answer below, with numbers you can find in the PDFs, and the six files from the ZIP still have their old names and dates.

Show the answer

Invoice MOS-2026-10418 (Meridian, March 10), line 2, the Townsend hybrid. Four bikes at $256.40 come to $1,025.60, but the invoice shows $1,053.05, which is $27.45 too high.

Invoice MOS-2026-10463 (Meridian, March 12), line 1, the e-bike charger. It bills 8 and goods-received shows 4, so 4 extra at $48.00 is $192.00 too high.

The Halloway and Lathwell invoices match exactly. If Claude also lists the tax on the two Meridian invoices, that's right and still a pass. Tax is 8.25% of the subtotal, so it's $2.27 and $15.84 too high ($2.26 for the first if worked out from $27.45 alone).

If Claude lists anything else, open it in the PDF and decide whether it's real. A mismatch it can't show you numbers for doesn't count. If it lists fewer than two, ask it to show how it checked the invoice it missed.

Two questions from memory

Before Cowork permanently deletes a file, what does it do?

It stops and shows a permission prompt, and waits until you select Allow. Anthropic says that applies in every mode.

Why did you work on a copy of the folder?

Claude can read, change and delete files in the folder you connect. Anthropic only promises a prompt before a file is deleted for good, so the copy protects your originals from everything else, such as a file being overwritten or renamed.

Course 2, lesson 1 opens by asking the first one again.

Want the same job every week?

Cowork can run a task on a schedule. Anthropic suggests starting with low-risk tasks and checking the results regularly, because scheduled tasks run while you're away. Lesson 7 sets the rules for what Claude may touch.

Your plan so far

What you've decided

First task for Claude
Who starts
Training setting
Profile
First Project for
Documents in it
Project instructions
Shared with the team
File storage
Folders Claude should use
Storage connected
Daily tools to connect
Mail and calendar
Routine turned into a Skill
Skill
Task handed to Cowork
Cowork run
Lesson 7 sets the rules for your team.