'at least 7 days of sales are needed'
Export a longer date range; 30 to 90 days works well.
A SKU shows 'sold but not in the stock list'
Add it to the stock list, or check the SKU is spelled the same in both files.
Order quantities look too high after a promotion
The promotion days raise the average. Export a typical period instead.
Claude does not use the skill
Check it is switched on in Settings → Capabilities → Skills, then name it in your message.
The script says a column is missing
Rename your header to one of the names in README, or say the mapping in your message.
Code execution is off
Skills with scripts need code execution enabled in Claude.ai settings.
FAQ
Which files work? Any sales export with a date, SKU and quantity per row, and a stock list with SKU and on-hand count. Lead time, supplier, cost and on-order columns are used when present.
How is safety stock worked out? z for the service level (1.65 for 95%) × the standard deviation of daily sales × the square root of the lead time in days.
Does it place orders? No. It writes a plan for you to check. Nothing is sent to suppliers.
Which service level should I use? 95% suits most SKUs. Use 97.5–99% for items that must never run out, and 80–90% for low-margin or bulky items.