Store refs
Every store-scoped call names its store as <store>-<CC> — the store and the marketplace in one string, taken verbatim from get_user_context.
A store ref is the store's name, a dash and the marketplace's country code: myStore-US, myStore-DE, myBrand-UK. noon accounts use the same shape, such as myNoon-AE. It is the store argument of every store-scoped tool — over MCP, over the Tool API and in the sidebar alike.
Take refs from get_user_context — never build one
get_user_context returns a ready-made store_refs list for each store. Your agent passes one verbatim. It never glues a name to a country code itself, and never guesses a marketplace: picking one by hand is how a call lands on a marketplace your plan doesn't cover.
No Amazon seller (SP-API) tool takes a separate country code — the ref already names the marketplace. The Amazon Ads tools are the exception: they also take a countryCode for the advertising profile.
A bare name is refused — with the answer
A bare store name (myStore) names the store but not the marketplace, so it is refused with a 400. The refusal lists every ref that would have worked, so your agent corrects itself in one step:
For a store selling in the US, Canada and Mexico, that is myStore-US, myStore-CA and myStore-MX.
A ref that matches two of your stores is refused too, the same way — rename one of them in the app.
Paused stores
A store whose every marketplace is inactive on your plan stops syncing, so its report data would be out of date. Rather than answer from stale data, SellerSheet refuses the store (403), naming it, your plan's usage and both remedies:
- upgrade the plan, or
- free a marketplace slot under My Stores → Edit Marketplaces — in the app, Settings → Stores & Marketplaces → Edit markets.
get_user_context marks such a store paused with the reason, so your agent knows before it picks a store. A store with only some marketplaces active is not paused: it keeps syncing those and answers for them.
noon marketplaces count against the same plan quota as Amazon ones, so a noon account can be the reason an Amazon marketplace is not active.
Stores shared with you
A store another account shares with you appears in your store_refs like your own. What you can do on it is what its owner granted you — and a key never reaches beyond that. See Stay in control.