Give Claude a folder for one bounded job

Example result.

summary.md: 5 items in kit-list.csv: 3 cleared, 2 awaiting check. Cleared: camera body, tripod, audio recorder (kit-list.csv, rows 2, 4 and 6). “Cleared” means the battery and lens check passed, not that the item is reserved (status-definitions.txt). Reservations: unknown. There is no reservations file in the folder. Source files changed: none.

1. Make a practice folder and connect it

Create a new folder and copy in only the files this job needs. Leave unrelated subfolders out, because connecting a parent folder hands Claude everything inside it.

It helps to be clear about what each route does. Uploading a file gives Claude a copy. Connecting a folder lets Claude read and write the real files on your computer. Telling it to “stay in this folder” in a prompt is a request, not a lock: the folder you connect is the real limit.

In the Claude desktop app, select Cowork in the message box. (On the newer layout there is no Chat/Cowork switch; describe the task in any conversation.) Choose your practice folder with the app’s folder option, then set the permission mode selector to Manual, so Claude asks before it acts and you choose Allow or Deny each time. Claude always asks before permanently deleting a file.

Start the task in the desktop app and keep the app open. A Cowork session started on the web can’t reach your local folders, and a session loses access to them while the app is closed. If you need only one excerpt, uploading or pasting it is simpler than folder access.

Why this works: the folder you connect decides what Claude can reach. A five-file folder is one you can check completely; your whole Documents folder is not.

What you should see: the practice folder named in the task, nothing above it, and Manual in the mode selector. If Cowork is missing or can’t see the folder, work through Troubleshoot Claude when it cannot see a file or finish a task before widening access.

2. Ask for a read-only inventory first

Before anything gets written, find out which files Claude can actually read. A sample from each file gives you something to compare against the original.

For this first stage, read only the folder [folder name] and make no file changes. The job is [result]. List the source files you can read, show two or three values or a short passage from each, and name any file you could not read or expected but could not find. Propose one new output file called [filename]. Do not rename, delete or edit any file, use other folders, connect services or send anything. Wait for my feedback on the plan.

[folder name] is the folder you connected. [result] is the job in one line, such as “a status summary of the kit list”. [filename] is the new file you want, such as summary.md.

Why this works: a short sample from each file is evidence you can check in a minute. Asking Claude to “tidy up the folder” to find out what is there is how originals get renamed.

What you should see: a list of files, a few values from each, a plan for one new file and no changes. Open the files and compare the samples. A correct filename with invented values doesn’t prove Claude read the file, and a correct value from row 2 doesn’t prove it read row 60.

3. Ask for one new file

Once the plan and samples check out, give the creation instruction in the same task.

Create only [filename] in [folder name], using the files you listed: [source files]. Include [what the summary must contain]. Leave missing information as unknown, and cite the filename and row or passage for each important fact. Do not change any source file. When you finish, report the output path, any files you changed and the checks you ran. Take no actions outside this folder.

[source files] are the filenames from step 2. [what the summary must contain] is your list of sections or counts, such as “item count by status and the meaning of each status”.

Why this works: naming one file and asking for a change report gives you something specific to check instead of “done”.

What you should see: in Manual mode, Claude asks before it writes. Check the filename in the request before you choose Allow. At the end, Claude reports one new file and no changed sources.

Check the result

• Open the new file yourself, from the folder, rather than reading Claude’s chat reply.
• Compare the counts and two or three cited rows with the source files.
• Check that every status word means what the source says it means.
• Look at the folder: one new file, and the source files’ modified dates unchanged.

The usual failure: the summary stretches a status word. “Cleared” becomes “reserved”, “ready” becomes “available on Friday”, and a date appears that no file contains. Spot it by searching the sources for every date and status word in the summary. If Claude says “done” without listing what it changed, treat the file as unchecked.

Return to the agreed scope: use only [source files] and change only [filename]. The current summary says [wrong claim], which [source file and row] does not support. Correct that line from the source, keep the facts you have already checked, and report every file you changed and any file you still cannot read.

[wrong claim] is the sentence that went too far. [source file and row] is where the real meaning lives.

Fictional example. A video team’s practice folder, shoot-kit, holds two files.

kit-list.csv
row 1  item,status
row 2  camera body,cleared
row 3  35mm lens,awaiting check
row 4  tripod,cleared
row 5  light panel,awaiting check
row 6  audio recorder,cleared

status-definitions.txt
Cleared means the battery and lens check has passed.
It does not mean the item is reserved for a shoot.

The step 2 inventory listed both files, quoted rows 2 and 5 and the definition line, and proposed summary.md. After step 3, the first version said:

Five items. Camera body, tripod and audio recorder are reserved for Thursday’s shoot. Lens and light panel awaiting check. Done.

The repair prompt from Check the result, filled in: [wrong claim] is “three items are reserved for Thursday’s shoot” and [source file and row] is status-definitions.txt, line 2. The corrected file:

5 items: 3 cleared (camera body, tripod, audio recorder), 2 awaiting check (35mm lens, light panel). Source: kit-list.csv, rows 2–6. Cleared means the battery and lens check passed, not reserved (status-definitions.txt). Reservations: unknown. There is no reservations file in the folder. Files changed: summary.md created. kit-list.csv and status-definitions.txt unchanged.

• The count was right; the meaning wasn’t. Five, three and two all match the CSV. The error was stretching “cleared”, which is why the check reads the definitions file and not only the numbers.
• Thursday came from nowhere. Neither file contains a date. Searching the sources for each date in the summary catches this in seconds.
• “Done” became a change list. The repaired report names one new file and two untouched ones. The folder’s modified dates confirm it.

Task kit for this job: Download (ZIP) · Reusable instructions

Go deeper

Add a second source without merging meanings

Suppose the team adds reservations.csv, which shows the tripod reserved for Tuesday. Thursday still appears nowhere. Copy the new file into the folder, run the step 2 inventory again for it, then ask for an update that keeps the two kinds of status apart.

Add [new file] to the sources for summary.md. Keep check status and reservation status as separate columns. Record only the reservations that file contains and leave every other item's reservation as unknown. Do not assume the other cleared items are free or reserved, and report the files you changed.

[new file] is the file you just added. The right result shows the tripod as cleared and reserved for Tuesday, the camera body and audio recorder as cleared with reservation unknown, and still no Thursday.

Keep the folder as the real limit

Cowork runs its code in an isolated environment, but that limits where code runs, not what Claude can read or change in the folders and apps you connect. Anything Claude reads, including a file or web page, can contain instructions written to mislead it, and the risk is highest when Claude can both read untrusted content and take actions. So keep Manual mode for folder work, don’t connect folders holding financial documents or other sensitive files, and keep a backup of anything that matters. If you work in Codex instead, Give Codex one practice folder and a clear job uses the same read-first, one-new-file pattern.

Leave a record for the next run

If the summary will be rebuilt every week, save a short note beside it: which source files and versions it used, the output path and the checks you ran. Next time, the step 2 inventory tells you whether a file is missing or new before Claude writes anything. For checking longer files, see Use business files and check the answer.

Sources

• Get started with Cowork (Claude Help Center)
• Use Claude Cowork on web, desktop and mobile (Claude Help Center)
• Use Claude Cowork safely (Claude Help Center)
• Install Claude Desktop (Claude Help Center)