Official MCP RegistryListed
WEM Price Compare
Price comparison across partner retailers. Read-only, 90-day history, disclosed affiliate.
First seen 2 Oct 2026. Evidence as of 7 Oct 2026.
11
Tools
From an anonymous probe
1
Source listings
Each with its own history
30
Recorded changes
Since first seen
Tools
| Tool | Description | Behaviour |
|---|---|---|
| compare_offers | Lists the retailer offers WEM's catalogue holds for one product, current prices first and each group cheapest first, with WEM's 90-day price low (null when the product is held only in another currency). The product is found by barcode, catalogue slug or wem3.ai/pl/ URL, WEM ID, or a title (a model name, ASIN, MPN or merchant SKU) that must pass a relevance check; there is no live retailer search. A barcode, slug or WEM ID match is the product itself; a title match is inferred and marked so in `identity`. A marketplace offer priced far below the product's other offers is withheld and counted in `filtered`. When WEM does not hold the product, `found` is false and `nextTool` names search_products with a query. | Read-only |
| compare_products | Lays 2 to 5 listings from earlier search results side by side in `comparison`: each listing's price and currency, and its rating, shipping and features where the retailer source supplies them (many listings carry none). Each item needs the listing's `provider` and its `id` as `product_id`. Listings that cannot be found are left out, and fewer than two found is an error. Prices stay in each listing's own currency. | Read-only |
| find_lowest_price | Picks one listing for a kind of product within the shopper's constraints, from WEM's catalogue and a live retailer search (a current catalogue match answers without the live search). Candidates are first filtered to plausible matches, so an accessory, another size, an out-of-stock listing or one priced far below the product's other offers is not picked. With no `priorities`, or with `cheapest` first, the lowest price wins; `best_rated`, `free_shipping` and `fastest` (has a delivery estimate) are weighed in the order given, where listings carry ratings or delivery details, and can outrank a lower price. WEM's commission is not a factor. `recommendation` is null with a reason when nothing matched confidently, when the matches differ in size, or when only stale prices remain; when `coverage.kind` is `marketplace_only` it is null but `alternatives` still lists the listings. `recommendation.verified` is true when WEM has recently observed that price at the retailer. | Read-only |
| get_categories | Lists the six broad shopping categories WEM covers (electronics, fashion, beauty, home, sports, collectibles), each with example products, the shops WEM has read a price from in the last 14 days (busiest first, with how many shops there are in all) and the default currency (GBP). Use it to help a shopper narrow a vague request. It returns no prices, the category names are labels for the shopper, not filter values, and a shop on the list is not a promise that WEM holds a given product there: compare_offers says which shops WEM has for one product. | Read-only |
| get_evidence_receipt | Fetches an evidence receipt by its id (wem-evr- followed by 32 hex characters), as issued with a verify_offer result. Returns the receipt's fields: verdict, observed_at, source, amount, currency and amount_minor, identity_method, verifier, standardVersion and issuedAt, with `signed` true and an HMAC `signature` when WEM signed it. It holds the citation, not the product's offers. A receipt issued moments ago may not be fetchable yet. | Read-only |
| get_product | Returns one product's details. Given `provider` and `product_id` from a search result, it returns that listing as its retailer source supplies it (title, price and link, with rating, shipping or features where the source has them); when the source cannot be reached it falls back to WEM's catalogue record of the listing, and an unknown listing is an error. Given `wem_id`, it returns that catalogue product with the retailer offers WEM holds for it. | Read-only |
| lookup_products | Looks up to 20 product identifiers in one call: barcodes (EAN/UPC/GTIN), Amazon ASINs, WEM IDs, catalogue slugs or wem3.ai/pl URLs. Each row has a status: found (WEM's catalogue holds it; the row gives its number of retailer offers, the lowest current price at a named retailer in the shopper's currency, a marketplace low where there is one, and a link to WEM's product page), not_found (WEM does not hold it yet, which says nothing about whether it exists or has a price), unrecognised (not an identifier, such as a product name) or not_checked (not reached in this call, so not a miss). Identifiers beyond 20 are counted in `overLimit`. | Read-only |
| search_products | Searches WEM's catalogue and its connected retailer sources for products matching a query. The query can be a product name or an identifier: a barcode (EAN/UPC/GTIN), an Amazon ASIN, an MPN, a merchant SKU that names one catalogue product, a WEM ID or a wem3.ai/pl/{slug} URL, and several identifiers may be comma-separated. When the query identifies a product WEM holds, a `catalogMatch` block (`catalogMatches` for several) gives that product's retailer offers; a barcode, ASIN, WEM ID or URL match skips the live retailer search, so `products` then holds catalogue offers only. Barcode, ASIN and slug matches are identity-resolved; MPN, SKU and title matches are inferred. Accessories, bundles, other models and listings priced far below the product's other offers are withheld and counted by reason in `filtered`. | Read-only |
| search_promotions | Lists current promotions (sales and offers) that retailers in WEM's Awin affiliate programmes have published, for the shopper's market. Filter by merchant or by words in the offer. Each row gives the offer, its dates and a tracked link. A promotion is not a price, and it is not a discount on a product unless its terms say it covers that product. Checkout codes are shown only where the retailer's programme lets WEM publish them; other matching promotions are counted by reason in `withheld`, and a withheld code may still exist. An empty result covers only these programmes, not every offer a retailer runs. | Read-only |
| semantic_search | Searches WEM's partner-feed products by meaning, for a plain-language need such as "comfortable shoes for standing all day" or "gift for a 10 year old who likes science". If the description is a product identifier (a barcode, ASIN, MPN, merchant SKU or wem3.ai/pl URL), that product is looked up instead and the reply takes the keyword-search shape. When no products come back, `reason` says why: `index_empty` means nothing matched; `no_embedding_key`, `no_catalogue_client`, `embedding_failed`, `query_failed` and `timed_out` mean the semantic index could not be searched this time, which says nothing about whether such products exist. | Read-only |
| verify_offer | Checks a price someone has claimed for a product against the prices WEM has itself observed at retailers (recent readings, within a small tolerance; not a live quote), and reports the cheapest observed offer. Identify the product by gtin (strongest), slug, wem_id, provider + externalId, or title (weakest, relevance-checked). `retailer` names the shop the claim is about; without it the nearest observed price at any shop is checked. Only offers in the claim's currency are compared. Verdicts: confirmed (WEM observed that price there), price_moved (WEM last observed a different price there), not_at_retailer (WEM has no observed price there, though it may hold a feed price), no_claim (no price given; the offers are returned), unknown_product (the product could not be resolved, or WEM holds no observed price for it in that currency). unknown_product means the claim could not be checked, not that it is false. `lastConfirmedAt` says when WEM last observed a price in the answer, or is null. Each call records an evidence receipt, whose id can be cited later. | Changes data |
Change history
- semantic_search: input schema changed
- search_products: input schema changed
- get_product: input schema changed
- get_categories: input schema changed
- get_categories: description changed (+"the shops WEM has read a price from in" +"last 14 days (busiest first, with how many shops there are in all)" +"values, and a shop on the list is not a promise that WEM holds a given product there: compare_offers says which shops WEM has for one product.")
- find_lowest_price: input schema changed
- compare_products: input schema changed
- compare_offers: input schema changed
- verify_offer: input schema changed
- verify_offer: description changed (+"Checks" +"someone has claimed for" +"against the prices WEM")
- semantic_search: input schema changed (+provider)
- semantic_search: description changed (+"Searches WEM's partner-feed" +"by meaning," +"a plain-language need such as")
- search_promotions: input schema changed
- search_promotions: description changed (+"Lists current" +"that" +"in WEM's Awin")
- search_products: input schema changed (+currency)
- search_products: description changed (+"Searches WEM's catalogue and its connected retailer sources" +"matching a query." +"can")
- lookup_products: input schema changed
- lookup_products: description changed (+"Looks" +"to 20 product identifiers" +"IDs, catalogue slugs")
- get_product: input schema changed
- get_product: description changed (+"Returns one product's details. Given `provider`" +"`product_id` from" +"result,")
- get_evidence_receipt: input schema changed
- get_evidence_receipt: description changed (+"Fetches an" +"its" +"(wem-evr- followed by 32 hex characters), as issued with")
- get_categories: description changed (+"Lists the six broad shopping" +"WEM covers (electronics, fashion, beauty, home, sports, collectibles), each with example products, plus the retailer sources currently enabled" +"default currency (GBP).")
- find_lowest_price: input schema changed (+condition)
- find_lowest_price: description changed (+"Picks one listing for a kind of" +"within" +"shopper's constraints, from WEM's catalogue and a live retailer search (a current catalogue match answers without")
- compare_products: input schema changed
- compare_products: description changed (+"Lays 2 to 5 listings from earlier search results" +"side in `comparison`: each listing's price" +"currency,")
- compare_offers: input schema changed
- compare_offers: description changed (+"Lists the retailer" +"WEM's catalogue holds" +"product, current prices first and each group")
- server instructions changed (+"Which WEM tool fits: compare_offers lists the retailer offers WEM holds for one product, found by barcode, WEM slug or wem3.ai/pl/ URL, WEM ID, or a model name or part number passed as title. verify_offer checks a price someone claimed for one product at one retailer. lookup_products checks up to 20 barcodes, ASINs, WEM IDs or product URLs at once. search_products finds products from a name or an identifier; semantic_search from a plain-language description of what the shopper needs. find_lowest_price picks one listing for a kind of product within the shopper's constraints, and does not resolve a specific model name. When verified is false the match was inferred from the name: it is not a confirmed identity and it is not the cheapest. Each offer's `url` opens that retailer's page for the offer WEM priced, and `links` lists them cheapest first. A retailer URL found elsewhere may be a different listing or price. Rows with `affiliate: false` earn WEM nothing, and `disclosure` says whether all, some or none of the links do. When there are no rows, a returned `search` link is WEM's results page for the query. Those links are in the text payload as well as in a rendered card.")
| Source | Listing | First seen | Last seen | Versions |
|---|---|---|---|---|
| Official MCP Registry | ai.wem3/wem-price-compare | 2 Oct 2026 | 7 Oct 2026 | 1 |