What Harness does with spreadsheets
Most spreadsheet work is repetitive: tidying an export, fixing dates that came out in three different formats, looking up values from another sheet, building the same monthly summary again. DeepSeek Harness does this work directly in your files. It opens the workbook, understands the columns, makes the changes and saves the result, while you check each step.
You don't need to know any formulas. Describe the outcome, such as "one row per customer with their total spend this year", and Harness works out how to get there. If you do know spreadsheets, you can ask for specific formulas, pivot-style summaries or a particular layout.
Excel - CSV
Workbooks with multiple sheets, plus plain CSV exports from other tools. Check the app for other formats.
A file you can open
Results are saved as a normal spreadsheet you can open, share and keep editing.
You approve changes
See the plan and a preview before anything is written. Keep the original as a backup.
Spreadsheet tasks you can hand over
| Task | What Harness does | Example request |
|---|---|---|
| Clean data | Trims spaces, fixes capitals, splits or joins columns, standardises dates and numbers | "Make all dates YYYY-MM-DD and remove extra spaces." |
| Remove duplicates | Finds exact and near-duplicate rows and explains what it would remove | "Remove duplicate customers, matching on email." |
| Summarise | Builds pivot-style totals, averages and counts by any column | "Total sales by region and month." |
| Write formulas | Adds formulas into the sheet so results update when the data changes | "Add a column with each order's tax at 18%." |
| Explain a sheet | Reads someone else's workbook and explains what each formula and tab does | "Explain how the forecast tab is calculated." |
| Merge - look up | Combines files or sheets and matches rows between them | "Add each product's price from prices.xlsx." |
| Reconcile | Compares two lists and shows what's missing, extra or different | "Which bank transactions aren't in the ledger?" |
| Charts | Creates charts from the data and places them on a summary sheet | "Add a monthly trend chart to a new Summary tab." |
| Convert - restructure | Reshapes wide data to long (or the reverse), splits one sheet into many, or turns a PDF table into rows | "Split this sheet into one file per branch." |
How a spreadsheet session works
- Open the folder that holds your spreadsheet(s) in Harness. New to Harness? Follow the setup steps first.
- Describe the result in plain language, and mention the file name if there are several.
- Review the plan. Harness says which columns it will use, how it will treat odd cases, and what it will produce.
- Check the preview: a few sample rows and the totals, so you can spot mistakes before the whole file is processed.
- Approve. The result is saved as a new file or a new sheet, so your original stays untouched.
Worked examples
Example 1 - Clean a messy export
Clean customers_export.csv: trim spaces, make names Title Case, put dates in YYYY-MM-DD, and remove duplicates that share an email address (keep the newest). Save as customers_clean.xlsx and tell me how many rows changed.
| Before | After |
|---|---|
" nimali PERERA " · 3/7/26 | Nimali Perera · 2026-07-03 |
"KAMAL silva" · 07-03-2026 | Kamal Silva · 2026-03-07 |
Two rows for ruwan@… | One row, keeping the most recent |
1,284 rows read · 311 names reformatted · 902 dates standardised · 37 duplicates removed. Six dates were ambiguous (they could be day/month or month/day) and are listed on a Check tab for you.
Example 2 - Monthly expense summary with a chart
Using bank_statement.csv, put each transaction into a category (rent, groceries, transport, utilities, eating out, other). Add a Summary sheet with totals per category for March and a bar chart. Use formulas so it updates if I fix a category.Harness sorts transactions into categories using the descriptions, flags the ones it isn't sure about, and builds the summary with live formulas rather than fixed numbers. Re-categorise a row and the totals and chart update on their own.
Example 3 - Reconcile two lists
Compare bank_march.xlsx with ledger_march.xlsx. Match on amount and date (allow ±2 days). Show me: transactions in the bank but not the ledger, in the ledger but not the bank, and matches where the amounts differ.
A new workbook with three tabs: Missing from ledger (4 rows), Missing from bank (2 rows) and Amount mismatch (1 row, a Rs 1,500 typo). Each row links back to the original line numbers so you can check it quickly.
Formulas, written and explained
Ask for a formula in plain English and Harness writes it into the right cells. Ask about an existing formula and it explains it in plain words. A few common examples:
| You ask | Formula Harness can write | What it does |
|---|---|---|
| "Total sales for the West region" | =SUMIFS(C:C, B:B, "West") | Adds column C only where column B says West. |
| "Look up each product's price" | =XLOOKUP(A2, Prices!A:A, Prices!B:B, "Not found") | Finds A2 on the Prices sheet and returns its price. |
| "Count orders over 10,000" | =COUNTIF(C:C, ">10000") | Counts the cells in C greater than 10,000. |
| "Flag late payments" | =IF(TODAY()-D2>30, "Late", "OK") | Marks a row Late if the date in D2 is more than 30 days ago. |
| "Month name from a date" | =TEXT(A2, "mmmm") | Turns a date into "March", "April" and so on. |
| "Remove extra spaces" | =TRIM(A2) | Removes spaces at the start and end, and doubled spaces in between. |
Automate recurring spreadsheet reports
If you build the same report every week or month, turn it into a scheduled task. Harness repeats the same steps on new files at the time you set.
Sales roll-up
Every Monday at 9:00, combine last week's branch files into one summary with a trend chart.
Expense report
On the 1st, sort last month's transactions into categories and save a summary for each person.
Stock check
Each evening, compare inventory with orders and list items below their reorder level.
Which model to use for spreadsheet work
| Task | Recommended model | Why |
|---|---|---|
| Cleaning, sorting, simple summaries | V4.1 Flash | Fast and cheap. The 1017 update improved multi-step tasks. |
| Complex formulas, reconciliations, financial logic | R1 | Reasons step by step and checks edge cases. |
| Long written analysis of the numbers | V4 Pro | Best at clear, polished explanations. |
Prompting tips for spreadsheets
| Do this | Why it helps | Example |
|---|---|---|
| Name the file and sheet | Avoids working on the wrong data. | "In sales.xlsx, sheet 'Q3'…" |
| Say how to match rows | Matching rules decide what counts as a duplicate or a match. | "Match on email, ignoring capital letters." |
| Give formats | Prevents inconsistent output. | "Dates YYYY-MM-DD, amounts in LKR, 2 decimals." |
| Say what to do with odd cases | Ambiguous rows are flagged, not guessed. | "Put anything unclear on a Check tab." |
| Formulas or values? | Decides whether results update later. | "Use formulas for the totals." |
| Ask for a new file | Keeps the original safe. | "Save as sales_clean.xlsx." |
| Ask for a short report | A quick way to check the work. | "Tell me how many rows changed and why." |
Accuracy and safety
| Risk | What can go wrong | How to avoid it |
|---|---|---|
| Wrong assumptions | A date like 03/07 is read as March 7 instead of 3 July. | State the format, and ask for unclear values to be flagged. |
| Overwriting data | The original file is changed by mistake. | Always ask for a new file, and keep a backup. |
| Formula errors | A range misses rows that are added later. | Check totals against a quick manual sum, and ask Harness to check its own totals. |
| Wrong categories | Transactions are sorted into the wrong group. | Review the flagged rows, and give examples of each category. |
| Sensitive data | File contents are sent to the model to be processed. | Remove personal or confidential columns first, or keep those files out of the working folder. |
| Financial decisions | Totals are used without being checked. | Treat results as a draft, and have important figures reviewed by a person. |
Troubleshooting
| Problem | Likely cause | Fix |
|---|---|---|
| "Can't open file" | The file is open in another app, password-protected, or outside the working folder. | Close it elsewhere, remove the password, and check the folder. |
| Strange characters | The CSV uses an unexpected text encoding. | Ask Harness to "detect and fix the encoding", or re-export the file as UTF-8. |
| Numbers treated as text | Thousands separators, currency symbols or spaces. | Ask it to "convert column C to numbers, removing Rs and commas". |
| Very large file is slow | Hundreds of thousands of rows. | Ask it to process the file in parts, or to use a script. See Harness Coding. |
| Formulas show errors | A sheet name or range has changed. | Ask Harness to "find and fix all formula errors". |
| Can't sign in or "server busy" | An account issue or peak demand. | See the login guide and updates. |
Harness for spreadsheets - frequently asked questions
Do I need to know Excel formulas?
No. Describe the result in plain English and Harness writes any formulas needed. It can also explain the formulas it writes.
Will it change my original file?
Only if you ask it to and approve the change. It's best to have it save to a new file or a new sheet.
Which file types work?
Excel workbooks and CSV files are the main ones. Check the Harness app for other formats.
Can it make charts?
Yes. Ask for the chart type, the data and where to put it, for example "a bar chart of totals by category on a new Summary tab".
Can it work with Google Sheets?
Harness works on files on your computer. Download the sheet as Excel or CSV, or connect cloud storage through a plugin if one is available.
Is it free?
Harness is free during the public preview. If you use an API key, normal token rates apply.
How is this different from using DeepSeek chat?
In chat you upload a file and get text back to copy. Harness edits and creates the actual files, can work across several at once, and can repeat the job on a schedule. Download the mobile app for chat on the go. For a broader comparison of AI assistants, see DeepSeek vs ChatGPT.
Is this an official DeepSeek page?
No. DeepSeekR1.com is an independent guide. See about us, our disclaimer, privacy policy and terms.