Previous value: -"Product or model name, e.g. Sony WH-1000XM5. Weakest identifier — used only when no barcode, slug, or WEM ID is available. Same relevance gate as verify_offer; a miss means fall back to search_products, not a guess."New value: +"Product or model name, or a bare MPN / merchant SKU (e.g. AF400UK). Weakest identifier — used only when no barcode, slug, or WEM ID is available. Same relevance gate as verify_offer; a miss means fall back to search_products, not a guess."

Previous value: -"Affiliate disclosure to relay once per answer. Outbound links are tracked at no extra cost to the buyer."New value: +"Disclosure to relay once per answer, verbatim. Its wording changes with the rows: it states whether every outbound link is affiliate-tracked, only some are, or none are. Never substitute the version you saw last time — a row marked `affiliate: false` earns WEM nothing, and saying otherwise misdescribes it to the shopper."

Previous value: -"False when the product is not in WEM’s catalogue. The rest of the fields below are then absent — do not read that as the product being unavailable or unpriced. Follow `nextTool`."New value: +"False when the product is not in WEM’s catalogue. The rest of the fields below are then absent — do not read that as the product being unavailable or unpriced. Check `unavailable` before describing the result, then follow `nextTool`."

Previous value: -"What re-reads this retailer’s prices: `live-api` a product-lookup API, `feed` a partner datafeed, `none` nothing at all. `none` means the figure is frozen at whatever seeded it and will not move however long it sits — say so rather than quoting it flat."New value: +"What re-reads this retailer’s prices: `live-api` a product-lookup API, `feed` a partner datafeed, `crawl` WEM reading the retailer’s own public product page, `none` nothing at all. `none` means the figure is frozen at whatever seeded it and will not move however long it sits — say so rather than quoting it flat. A `crawl` price was observed on the retailer’s page rather than supplied by them, so date it with `priceAgeDays` and expect `affiliate: false` unless a programme also exists."

Previous value: -[
-  "live-api",
-  "feed",
-  "none"
-]New value: +[
+  "live-api",
+  "feed",
+  "crawl",
+  "none"
+]

Previous value: -"Present only when `found` is false: which identifier missed, and why."New value: +"Present only when `found` is false: which identifier missed, and why. When `unavailable` is true this describes the outage rather than a missing product — quote it as the reason the lookup failed, not as a fact about the product."

Added value: +{
+  "description": "Present and true only when WEM could not reach its catalogue at all. `found` is false for the same reason it is on an ordinary miss, so the two are indistinguishable without this flag. When it is set, WEM does not know whether it holds the product: say the lookup could not be completed, never that WEM has no offers, no price, or does not stock it. Still call `nextTool` — the live retailer search does not depend on the catalogue.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Present when this result names no offer. GIVE THE USER THIS LINK — it is the answer when WEM has nothing else to say, and `markdown` is ready to paste. WEM searches retailers live on that page, including shops it holds no affiliate programme with, so an empty or withheld result here is not evidence the product is unavailable or unpriced.",
+  "properties": {
+    "markdown": {
+      "description": "The same link, pre-formatted.",
+      "type": "string"
+    },
+    "reason": {
+      "type": "string"
+    },
+    "url": {
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

Previous value: -"Every verified retailer offer for one catalogue product, cheapest first."New value: +"Every verified retailer offer for one catalogue product, cheapest first. When `found` is false WEM simply does not hold this product yet — that is a normal answer, not a failure, and it says nothing about whether the product exists or what it costs. Call `search_products` with `nextTool.query` before telling the user anything; reporting \"WEM returns nothing\" without doing so is wrong, because the live retailer search routinely finds supply this catalogue has not ingested."

Added value: +{
+  "description": "False when the product is not in WEM’s catalogue. The rest of the fields below are then absent — do not read that as the product being unavailable or unpriced. Follow `nextTool`.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Present only when `found` is false: the call to make next, with the text to pass. This is the recovery path, not a suggestion — a named model that misses the catalogue is the ordinary case, and the live search is where its offers are.",
+  "properties": {
+    "query": {
+      "type": "string"
+    },
+    "tool": {
+      "enum": [
+        "search_products"
+      ],
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

Added value: +{
+  "description": "Present only when `found` is false: which identifier missed, and why.",
+  "type": "string"
+}

Previous value: -[
-  "product",
-  "offers",
-  "priceHistory",
-  "source",
-  "disclosure"
-]New value: +[
+  "found"
+]

Added value: +{
+  "description": "Present when `price` is the OPENING price of a range, not the price of this item: a multi-variation listing where the seller advertises its cheapest variant and the shopper picks a size on the page. Quote it as \"from £X\", never as the price or the cheapest. Absent means the price is firm for the row as described.",
+  "enum": [
+    "from"
+  ],
+  "type": "string"
+}

Added value: +{
+  "description": "ISO 4217 code for the shopper's market. Default GBP. Decides which retailers are searched, not just how the answer reads — pass it explicitly, because WEM does not infer the market from IP. When WEM holds the product only in another currency it says so rather than presenting a foreign listing as the answer.",
+  "type": "string"
+}

Added value: +{
+  "description": "retailer is a named shop (Boots, Currys). marketplace is eBay/AliExpress/Temu-style parallel listings. Do not present a marketplace cluster as competing authorised retailers.",
+  "enum": [
+    "retailer",
+    "marketplace"
+  ],
+  "type": "string"
+}

Added value: +{
+  "description": "Delivery window when the feed stated one.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Previous value: -"Present when every surviving row is a marketplace listing clustered at similar prices. That is not a retail floor — do not name the cheapest as the deal, and do not present the listings as competing retailers. WEM does not hold an authorised retailer for this product."New value: +"Present when surviving rows include a marketplace cluster at similar prices. That is not a retail floor — do not name the cheapest marketplace listing as the deal. The listings are still in the payload; give the user those links. If `next` points at the Chrome extension, send the shopper there for shops WEM does not yet hold as partners."

Added value: +{
+  "description": "Where to send the shopper when WEM's set is thin. chrome_extension means compare the same product on any retailer page — WEM shows that price even without an affiliate programme.",
+  "properties": {
+    "reason": {
+      "type": "string"
+    },
+    "surface": {
+      "enum": [
+        "chrome_extension"
+      ],
+      "type": "string"
+    },
+    "url": {
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

Added value: +{
+  "description": "False when this is a retailer page WEM observed without a programme. Still a real listing; the click is not commission-bearing. Absent means the usual partner path.",
+  "type": "boolean"
+}

Added value: +{
+  "description": "Present when every surviving row is a marketplace listing clustered at similar prices. That is not a retail floor — do not name the cheapest as the deal, and do not present the listings as competing retailers. WEM does not hold an authorised retailer for this product.",
+  "properties": {
+    "currency": {
+      "type": "string"
+    },
+    "high": {
+      "type": "number"
+    },
+    "kind": {
+      "enum": [
+        "marketplace_only"
+      ],
+      "type": "string"
+    },
+    "listings": {
+      "type": "number"
+    },
+    "low": {
+      "type": "number"
+    },
+    "provider": {
+      "description": "ebay, aliexpress, or marketplace when mixed.",
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

Previous value: -"When WEM last read these offers — the freshness of this answer. Same field verify_offer publishes."New value: +"When WEM last actually read any price in this answer. Null means none of them can be dated — say so rather than implying the answer is current."

Previous value: -"When WEM last wrote this offer row."New value: +"When WEM last VISITED this offer row — not when it read the price. The refresh sweep touches this even when the retailer lookup fails, so it is not evidence the price is current. Use `priceAgeDays` to date a price; never this."

Previous value: -"Whole days since WEM last wrote this price. Null means unknown age — report it as unknown rather than assuming it is current."New value: +"Whole days since WEM last actually READ this price from the retailer or a datafeed. Null means WEM cannot say — common and correct for Amazon, whose licence caps price retention at 24 hours. Report null as undated; never present it as current."

Added value: +{
+  "description": "The tracked links from `offers`, cheapest first, pre-formatted to quote. Give these to the user when you name an offer: they carry the attribution WEM is funded by, and a retailer URL you compose yourself does not. Present even when the host renders a WEM card — never assume the card reached the user.",
+  "items": {
+    "properties": {
+      "currency": {
+        "type": "string"
+      },
+      "markdown": {
+        "description": "The same link as `[Retailer — £0.00](url)`, for hosts rendering markdown.",
+        "type": "string"
+      },
+      "price": {
+        "type": "number"
+      },
+      "retailer": {
+        "type": "string"
+      },
+      "url": {
+        "description": "WEM tracked redirect. Relay it exactly; never rewrite or shorten it.",
+        "type": "string"
+      }
+    },
+    "type": "object"
+  },
+  "type": "array"
+}

Added value: +{
+  "description": "When WEM last read these offers — the freshness of this answer. Same field verify_offer publishes.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Added value: +{
+  "description": "When WEM last wrote this offer row.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Added value: +{
+  "description": "Whole days since WEM last wrote this price. Null means unknown age — report it as unknown rather than assuming it is current.",
+  "type": [
+    "number",
+    "null"
+  ]
+}

Added value: +{
+  "description": "What re-reads this retailer’s prices: `live-api` a product-lookup API, `feed` a partner datafeed, `none` nothing at all. `none` means the figure is frozen at whatever seeded it and will not move however long it sits — say so rather than quoting it flat.",
+  "enum": [
+    "live-api",
+    "feed",
+    "none"
+  ],
+  "type": "string"
+}

Previous value: -[
-  {
-    "required": [
-      "gtin"
-    ]
-  },
-  {
-    "required": [
-      "slug"
-    ]
-  },
-  {
-    "required": [
-      "wem_id"
-    ]
-  }
-]New value: +[
+  {
+    "required": [
+      "gtin"
+    ]
+  },
+  {
+    "required": [
+      "slug"
+    ]
+  },
+  {
+    "required": [
+      "wem_id"
+    ]
+  },
+  {
+    "required": [
+      "title"
+    ]
+  }
+]

Added value: +{
+  "description": "Product or model name, e.g. Sony WH-1000XM5. Weakest identifier — used only when no barcode, slug, or WEM ID is available. Same relevance gate as verify_offer; a miss means fall back to search_products, not a guess.",
+  "type": "string"
+}

Added value: +{
+  "description": "How the product was identified. Never present a strength of \"inferred\" as a barcode-exact identity.",
+  "properties": {
+    "method": {
+      "enum": [
+        "gtin",
+        "slug",
+        "listing",
+        "title"
+      ],
+      "type": "string"
+    },
+    "strength": {
+      "description": "exact = barcode; catalogued = a WEM key or listing id; inferred = matched on the product name and still a guess.",
+      "enum": [
+        "exact",
+        "catalogued",
+        "inferred"
+      ],
+      "type": "string"
+    }
+  },
+  "type": [
+    "object",
+    "null"
+  ]
+}

Previous value: -"Ascending by price. Every row IS the product — resolved by barcode, not by title."New value: +"Ascending by price. Barcode, slug and WEM ID rows are the product. A title match is inferred — check identity.strength before stating it as exact."

Added value: +[
+  {
+    "required": [
+      "gtin"
+    ]
+  },
+  {
+    "required": [
+      "slug"
+    ]
+  },
+  {
+    "required": [
+      "wem_id"
+    ]
+  }
+]

Removed value: -[]

Added value: +{
+  "description": "Why the offers are in this order. Offers are ordered by price, lowest first; affiliate commission is not an input.",
+  "properties": {
+    "basis": {
+      "type": "string"
+    },
+    "parameters": {
+      "description": "The published ranking parameters.",
+      "type": "string"
+    },
+    "reason": {
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

Added value: +{
+  "description": "WEM ID (W + 10 Crockford characters + check). Active catalogue products only.",
+  "type": "string"
+}

Added value: +{
+  "description": "WEM ID of this active product. Omit when unknown; never invent one.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Previous value: -"WEM canonical product slug, as in wem3.ai/pl/{slug}."New value: +"WEM catalogue slug, or a wem3.ai/pl/{slug} URL / host path. Hosts may pass either form."

Added value: +{
+  "description": "Product photo, served from wem3.ai. Null when none is available — do not substitute one.",
+  "type": [
+    "string",
+    "null"
+  ]
+}

Previous value: -nullNew value: +{
+  "description": "Every verified retailer offer for one catalogue product, cheapest first.",
+  "properties": {
+    "currency": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "disclosure": {
+      "description": "Affiliate disclosure to relay once per answer. Outbound links are tracked at no extra cost to the buyer.",
+      "type": "string"
+    },
+    "highPrice": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "lowPrice": {
+      "type": [
+        "number",
+        "null"
+      ]
+    },
+    "offers": {
+      "description": "Ascending by price. Every row IS the product — resolved by barcode, not by title.",
+      "items": {
+        "properties": {
+          "brand": {
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "currency": {
+            "description": "ISO 4217 code.",
+            "type": "string"
+          },
+          "id": {
+            "type": "string"
+          },
+          "image": {
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "inStock": {
+            "type": [
+              "boolean",
+              "null"
+            ]
+          },
+          "price": {
+            "description": "Indicative price. The retailer sets the final price at checkout.",
+            "type": "number"
+          },
+          "provider": {
+            "description": "Retailer slug, e.g. \"ebay\", \"currys\".",
+            "type": "string"
+          },
+          "rating": {
+            "type": [
+              "number",
+              "null"
+            ]
+          },
+          "reviewCount": {
+            "type": [
+              "number",
+              "null"
+            ]
+          },
+          "seller": {
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "shipping": {
+            "properties": {
+              "cost": {
+                "type": [
+                  "number",
+                  "null"
+                ]
+              },
+              "free": {
+                "type": "boolean"
+              }
+            },
+            "type": [
+              "object",
+              "null"
+            ]
+          },
+          "title": {
+            "type": "string"
+          },
+          "url": {
+            "description": "WEM tracked link to the retailer. Send the user here — WEM never takes payment.",
+            "type": "string"
+          },
+          "verified": {
+            "type": "boolean"
+          }
+        },
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "priceHistory": {
+      "description": "The 90-day low, for telling a real discount from a repackaged one.",
+      "properties": {
+        "days": {
+          "type": "number"
+        },
+        "low": {
+          "type": [
+            "number",
+            "null"
+          ]
+        }
+      },
+      "type": "object"
+    },
+    "product": {
+      "properties": {
+        "brand": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "gtin": {
+          "description": "The barcode identity was resolved on.",
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "slug": {
+          "type": "string"
+        },
+        "title": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "slug",
+        "title"
+      ],
+      "type": "object"
+    },
+    "source": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "product",
+    "offers",
+    "priceHistory",
+    "source",
+    "disclosure"
+  ],
+  "type": "object"
+}