Last updated: Oct 15, 2026 at 11:30AM
If the AI keeps answering a field differently than you'd like — your sizing conventions, your tone, a measurement your brand defines its own way — write it down once as a custom instruction on that field. Every future Prompt that touches the field follows your guidance automatically.
Add instructions to a field
- In the sidebar, open your marketplace and click Fields.
- Search for the field and open it. It opens on its Settings tab.
- On the Settings for all categories card, turn on Extra instructions and write your guidance in plain English.
- Click Save on the card.
As a shortcut, on a listing's Fields tab open the ... menu on any field's row and choose Field -> Settings. The field opens with the listing's category picked on its Instructions tab and in Add category-specific setting.
Turning Extra instructions off and saving removes your instructions. Until you leave the page, turning it back on brings back what you'd written.
What to write
Short, specific, factual statements work best:
- "Sleeve length is measured from the center back of the neck, not the shoulder seam."
- "Our fits run small — when choosing a fit description, size up."
- "Never mention other brand names in descriptions."
The same card has a Use a fixed value switch. Off (the default), the AI decides how to fill the field from all your product data. On, every listing gets the value you pick and the AI leaves the field alone, so the card hides Extra instructions. Saving a fixed value, changing it or turning it off updates your existing listings as a bulk action, with one row per listing, so you can follow it on the Bulk Actions page under Data (see Create listings in bulk). Saving the same field again before it finishes cancels the earlier run and starts a fresh one. To stop a field being filled at all, turn off Enabled under Status; the card then hides the fixed value and extra instructions too.
Formatting your instructions
Instruction boxes support Markdown, and you can write them either of two ways. A small toggle in the box's top-right corner switches between them at any time:
- Rich text — a toolbar for bold, italic, headings, bullet and numbered lists, inline code, code blocks, quotes, links and tables. Formatting is applied as you type.
- Markdown — the raw markdown source, if you'd rather type
**bold**and-yourself.
Both write the same thing, so switching never changes what you've written. Placeholders like {{ product_type }} and names with underscores are preserved exactly as typed in either view.
Formatting is optional — plain sentences work well. Headings and lists mostly help when a field needs several distinct rules.
Tables
Click the table button in the toolbar to insert a 3×3 table with a header row. Put the cursor in any cell and a second row of controls appears underneath the toolbar for adding and removing rows and columns, toggling the header row, or deleting the table.
Tables are saved as standard markdown pipe tables, so they stay readable and editable in Markdown view too. If you need a literal | inside a cell, type it normally — it's escaped for you when saved.
Tables are useful for anything with repeating structure, like a size chart or a per-category rule:
| Category | Rule |
|---|---|
| Dresses | Measure length from the shoulder seam |
| Knitwear | Always mention the fibre blend |
To choose which view instruction boxes open in by default, set Editor on your Preferences page.
Per-category instructions and settings
The same marketplace field can need different handling in different product categories. The field's Settings tab has two parts for this:
- Settings for all categories is the status, fixed value and extra instructions every category uses unless it sets its own.
- Category-specific settings lists the categories with their own. Overridden means the category sets its own status or fixed value, and Present means it has extra instructions. Each row's ... menu can Edit or Delete it, or Preview instructions for it.
The Instructions tab shows what the AI ends up with for all categories or one. Pick the category on its Category card, which lists the categories where you or the marketplace set something; it's left out when no category has anything of its own, or when the field has a fixed value for all categories and none of your category-specific settings. The Instructions card says whether the marketplace requires the field there, then Skip this field. when it's disabled, Use fixed value: and the value when there is one (with an Edit link to where it's set), otherwise each set of instructions in the order the AI reads them. Each of your own has an Edit link, and where you have none for all categories or for the picked category, a link to add them.
A field that picks the listing's category has no category-specific settings.
To add one, click Add category-specific setting, choose the category (for a field only some categories have, the list holds just those categories and the ones above them), then turn on Override status? or Override fixed value? to set its own, or turn on Extra instructions and write some for it, and click Save at the top of the page. Off, an override inherits the setting from the category's parent, or from all categories, and the page says which. Changing a status or fixed value also updates your existing listings as a bulk action you can follow on the Bulk Actions page.
The Details tab shows the marketplace's details for the field, such as its type and whether it fills the parent listing or each variant.
Category settings and instructions also apply to the category's subcategories. When a category and one of its parent categories both set a status or fixed value, the nearest category wins. Instructions add up instead: the AI reads the marketplace's instructions, your defaults, then your instructions for each category from the broadest to the most specific.
A field's Applicable Categories tab, the last one, lists the categories the marketplace uses it in. To list the fields that apply to a category, open Fields and filter by Category. The Enabled column then shows each field's status for that category, and opening a field previews it for that category.
Marketplaces have category-specific requirements of their own, too. Macy's, for example, wants a Highlights bullet for length, neckline and lining on Women's Outerwear. Osello maintains those and adds them to the field's instructions for listings in that category and its subcategories. You'll find them on the field's Instructions tab once you pick the category, and on the public marketplace directory.
When you edit a listing's field value, the Instructions & Description panel shows the instructions that apply to that listing: the marketplace's and yours, for all categories and for the listing's category. Below them, Requirements lists the field's limits for that category, such as its maximum length, how many items it takes, its allowed units, or its options when there are fewer than 50. The AI reads the same text before it fills the field.
Ask the AI to save an instruction for you
You can also teach the AI from a listing's or variant's AI Chats tab. Tell it plainly that you want something applied going forward — "From now on, measure sleeve length from the center back of the neck" or "Remember: any SKU containing ABC-123 belongs in the Outdoor Lighting category" — and it adds the rule to that field's custom instructions for the whole marketplace, below anything you've already written there. Open the field's Settings tab afterwards and you'll see it under Extra instructions on the Settings for all categories card, ready to tweak.
A few things to know:
- The AI only saves an instruction when you ask it to remember something. Asking it to fix a value on the listing in front of you changes that value, not the field's instructions.
- Saved rules are general by design. The AI won't write a rule about one specific listing or product, because every future fill of the field across the marketplace reads it — rules about SKU patterns, product types, or how your brand measures things are the right fit.
- Rules saved this way apply to the field in every category of that marketplace. For a category-only rule, use the per-category instructions described above.
- Saving a rule doesn't change existing values — re-run the field to apply it (see "When instructions take effect" below).
Store-wide instructions
For guidance that should shape everything the AI writes, open the store menu at the bottom of the sidebar, choose Profile & Preferences, and go to the Listing Settings tab. The Universal Custom Instructions box applies across every marketplace on your store. Your Store Profile — especially "What do you sell?" — also feeds the AI context about your catalog, so it's worth filling in well.
When instructions take effect
Instructions apply to every Prompt that runs after you save them. Existing values don't change on their own — re-run the field (choose Update with AI on the field's row, or run Fill in With AI with Skip filled values unchecked) to apply your new guidance. To confirm they were used, open the prompt's field detail: the "Instructions Followed" section shows exactly what the AI was told.