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Working from your own files and images

In this lesson we hand an assistant a screenshot of a table and get the rows back for a spreadsheet. First we try to describe the table in words and see where that goes wrong. Then we upload the picture with a brief that says what to keep exact. The check is a count of the cells that came back wrong. A second run compares two versions of a short contract, where the brief says which differences matter. By the end you have a rule for working with files and images: when to upload and when to type.

You need a chat assistant that accepts images. Most do, and the one this lesson checks its limits against takes pictures in the common formats up to 8000 by 8000 pixels each, about twenty of them in one message, and a file size limit that changes between products and over time, so check the one your product states [1]. Every response shown here is illustrative. The author wrote it to show the pattern, and your model gives a different text.

The table

Section titled “The table”

Here is the material. It is a stock count from Brindlewick Instruments, the fictional company from the previous lesson, and it exists only as a picture: someone photographed the count sheet, or took a screenshot of a system you have no export from. The task is to get these six rows into a spreadsheet.

A screenshot of a table titled "Storeroom B, stock count, 18 September" with six rows and the columns Item code, Description, Shelf, Counted, Expected and Difference.

Look at it once now. Thirty-six cells, some of them one digit, some of them a minus sign in front of a digit. You could type them, and typing is where a -1 becomes a 1. The point of this lesson is to make the assistant do the typing and to make the check quick.

Describe the table in words

Section titled “Describe the table in words”

The first instinct is to describe what you see. Before you read on, predict what comes back when you do that. Where does the assistant get the values you leave out?

Prompt (illustrative, not a recorded transcript)

I have a stock count table with six rows. The columns are item code, description, shelf, counted, expected and difference. The items are a torque wrench, a calibration weight, two digital calipers, a thermocouple probe and a spirit level. The item codes start with BI and a dash and a four-digit number. Can you give me the rows to paste into a spreadsheet?

Response

Here is the table as tab-separated rows. I have filled in the codes and numbers as placeholders where you did not give them, so replace those with the real values.

Item code  Description  Shelf  Counted  Expected  Difference
BI-0001  Torque wrench  B1  10  10  0
BI-0002  Calibration weight  B1  5  5  0
BI-0003  Digital caliper  B2  12  12  0
BI-0004  Digital caliper  B2  12  12  0
BI-0005  Thermocouple probe  B3  8  8  0
BI-0006  Spirit level  B3  4  4  0

The response says so itself, and it is still no use. The numbers are made up, because the prompt gave none, and the two calipers are indistinguishable because the prompt did not say how they differ. You would now type thirty numbers into the assistant’s placeholders, which is the work you wanted to hand over. A description is a lossy copy of the picture, and the loss is in the exact values, which is the one part of the task that matters.

Upload the screenshot

Section titled “Upload the screenshot”

Now attach the picture. Save the screenshot from this page to your computer, open a fresh chat, add the file to the message, and write the ask under it. The brief has the parts you used for the expense guideline in the previous lesson. The goal is rows for a spreadsheet. The context is the attached file, named as the only source. The limits say what to keep exact and what to leave out. The done-criterion is one you can check against the picture.

Prompt (illustrative, not a recorded transcript)

[stock-count.png attached]

Attached is a screenshot of a stock count. Give me every row as tab-separated values that I can paste into a spreadsheet, with the header row first and the rows in the same order as the picture. Keep the item codes and the numbers exactly as shown, including the sign. Do not add a total or any row that is not in the picture. Where a cell is unreadable, write a question mark instead of guessing.

Response
Item code  Description  Shelf  Counted  Expected  Difference
BI-1042  Torque wrench 20-100 Nm  B3  14  15  -1
BI-1108  Calibration weight 1 kg  B1  8  8  0
BI-2260  Digital caliper 150 mm  B4  21  19  +2
BI-2271  Digital caliper 300 mm  B4  6  6  0
BI-3015  Thermocouple probe, type K  B2  37  40  -3
BI-3390  Spirit level 600 mm  B5  11  11  0

Paste the rows into a spreadsheet and put the picture next to it. Go through the cells one at a time and count the ones that differ from the picture. On a clear screenshot like this one the count is zero or one, and the cells that go wrong are the ones a person mistypes too: a sign dropped from a negative number, or a 1 read as a 7. The vendor’s own documentation says that the model reads small, blurry or rotated text badly and that its counts of objects are approximate. It recommends text that is legible in the picture. A crop that makes the text larger should still show the context around it, such as the header row [1]. The check is what tells you which kind of picture you have.

The upload changed the task. You wrote one sentence about the file and three about what to keep exact, and the assistant did the thirty-six cells. The same brief works for a photo of a whiteboard, a PDF price list, a spreadsheet export, or a scanned form. Name the attachment as the source and say what must be copied exactly. Give the model a way to say “I can’t read this”, so that it doesn’t fill the gap.

Checkpoint · choice

Which ask gets the table?

Section titled “Which ask gets the table?”

You have the screenshot of the stock count and a chat open. Which ask gets you rows you can paste and check in a minute?

Compare two versions of a contract

Section titled “Compare two versions of a contract”

Here is a second use of the same move. A short service agreement has come back from the other side with changes, and you want to know what changed. The versions are below, and each is short on purpose so that you can check the answer. In your own work they would be two files, and you attach both.

Service agreement, calibration services (version 1)

  1. Brindlewick Instruments calibrates the Client’s measuring equipment listed in Schedule A once every twelve months.
  2. The fee is 1,200 euros per visit, invoiced after each visit and payable within 30 days.
  3. Either party may end this agreement with 60 days’ written notice.
  4. Brindlewick repeats a faulty calibration free of charge when the Client reports it within 14 days of the visit.
  5. Brindlewick keeps the calibration records for five years and provides copies on request.
  6. Brindlewick may not subcontract the work without the Client’s written consent.

Service agreement, calibration services (version 2)

  1. Brindlewick Instruments calibrates the Client’s measuring equipment listed in Schedule A once a year.
  2. The fee is 1,350 euros per visit, invoiced after each visit and payable within 30 days.
  3. Either party may end this agreement with 30 days’ written notice.
  4. Brindlewick repeats a faulty calibration without charge when the Client reports it within 14 days of the visit.
  5. Brindlewick keeps the calibration records for five years and provides copies on request.
  6. Brindlewick may subcontract the work to a certified laboratory and remains responsible for it.

“Compare these two” gives you a list in which a fee increase and a changed turn of phrase sit side by side with the same weight. The brief says which differences matter and what to do with the rest.

Prompt (illustrative, not a recorded transcript)

[contract-v1.txt and contract-v2.txt attached]

Attached are two versions of a service agreement. List every difference that changes an amount, a period, a deadline or an obligation. For each one, quote the sentence from both versions. Rewording that keeps the meaning goes in one line at the end, and if a clause is unchanged, do not mention it.

Response
  1. Fee. Version 1: “The fee is 1,200 euros per visit”. Version 2: “The fee is 1,350 euros per visit”.
  2. Notice period. Version 1: “with 60 days’ written notice”. Version 2: “with 30 days’ written notice”.
  3. Subcontracting. Version 1: “Brindlewick may not subcontract the work without the Client’s written consent.” Version 2: “Brindlewick may subcontract the work to a certified laboratory and remains responsible for it.” The Client’s consent is no longer needed.

Rewording only: clause 1 says “once a year” instead of “once every twelve months”, and clause 4 says “without charge” instead of “free of charge”.

Check it against the two texts. Each of the three items quotes both versions, so the check is finding two sentences, and the reworded clauses are named and set aside rather than mixed in. The brief did that. It named the kinds of change that matter (amount, period, deadline, obligation), asked for the quote behind each, and gave the rewording a place to go.

Checkpoint · sort

Which differences does the brief ask for?

Section titled “Which differences does the brief ask for?”

What an upload discloses

Section titled “What an upload discloses”

An attachment goes to the same place as pasted text, under the same terms, and the model reads all of it. The difference is that you read pasted text as you paste it, and you rarely read a file before you attach it. In the lesson on redacting before you paste you read a document with the task in mind and split it into what the task uses and what says who is involved. Do the same with a file, and where a file holds both, make a copy that holds only the first part: crop the screenshot, or export the one sheet.

Checkpoint · scenario

Which file goes in the brief?

Section titled “Which file goes in the brief?”

You want a chart of the daily totals column from the team’s spreadsheet, two hundred rows of it. The sheet also has a column of names and a column of salaries. What do you attach?

When to upload and when to type

Section titled “When to upload and when to type”

Upload when the material is long, structured or visual: a table, a diagram, a photo of a whiteboard, a document with numbering you want kept. Describing it loses the exact values, and the exact values are the task. Type when the material is one or two sentences, or when the file holds things the task doesn’t need and you can’t cut them out in a minute.

Either way the brief is the one you wrote for the expense guideline in the previous lesson, with the attachment in place of the pasted text. Name the file as the source, say which values must be copied exactly, give the model a way to say it can’t read something, and check the result against the file. A read of a picture is a transcription, and a transcription error is silent until you look.

Exercise

Save the stock count screenshot from this page, open a fresh chat, attach it, and send the brief from the “Upload the screenshot” section. Paste the rows into a spreadsheet and compare them with the picture, cell by cell, and write down the number of cells that differ and what each one says. It takes about five minutes and produces one number and at most a few lines. Doing it once by hand shows you what kind of error a picture read makes, so you know what to check for next time. A good result is a count you can name, with a line for each wrong cell, and zero is a fine count. Which of the wrong cells, if any, would you have got wrong yourself if you had typed the table?

Stretch: Shrink the screenshot to half its width in any image editor, run the same brief on the smaller copy, and see whether the count of wrong cells changes.

Recap

  1. A description of a table is a lossy copy of it, and the loss is in the exact values. Attach the picture or the file, and let the model do the typing.
  2. The brief for an upload has the same four parts as any other. Name the attachment as the only source, say which values must be copied exactly, and give the model a way to say it can’t read a cell.
  3. Check the result against the file, cell by cell. A model reads small, blurry or rotated text badly, and a transcription error is silent until you look [1].
  4. When comparing two files, say which kinds of difference matter and where the rest should go, and ask for the quote from both versions behind each one.
  5. An attachment discloses its whole content, the same as pasted text. Crop or copy out the part the task needs before you attach.

You can now

  • Writes a brief with goal, context, limits and done-criteria

References

Section titled “References”
  1. Anthropic. Vision. Claude Platform documentation. Reference. Claude docs vision