openfoodfacts-mcp-server

Compare Food Products Side-by-Side

off_compare_products

Read-onlyIdempotent

Side-by-side nutrition and scoring comparison for 2–10 products by barcode. Returns a normalized table of energy (kcal/100g), fat, saturated fat, sugars, salt, protein, fiber, Nutri-Score, NOVA group, and Green-Score. Designed for "which of these cereals is healthiest?" or "compare these pasta brands" workflows. Missing nutrition data for any product is preserved as absent — comparisons are not imputed. A batch is not all-or-nothing: barcodes that resolve are returned even when others fail, with confirmed-missing barcodes listed in not_found and failed fetches listed separately in failed. Scores carry regional formula caveats. Data under ODbL 1.0 — cite Open Food Facts in downstream use.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`barcodes`	Yes	2–10 barcodes to compare, returned as one row each in input order. Example: ["3017620422003", "7622210100146"].

Output Schema

TableJSON Schema

Name	Required	Description
`error`	No	Present when the call failed. Absent on success.
`failed`	No	Barcodes whose fetch failed, with the per-barcode reason. Absent when every fetch completed. A barcode listed here is unknown, not absent from Open Food Facts — retry it with off_get_product before concluding anything about the product.
`products`	No	Comparison rows in input order — one per barcode whose fetch completed, whether or not a record exists. Barcodes whose fetch failed have no row here; they appear in failed.
`not_found`	No	Barcodes Open Food Facts answered for, confirming no contributor record exists. Not an error — the product may exist but not yet be entered. Never used for a fetch that failed.
`succeeded`	No	Number of barcodes that resolved to a found product.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 8, 2026

changedOutput schema / properties / error / properties / data / properties / reason / description

Previous value: -"Machine-readable failure mode. Declared by this tool: `upstream_error`: Open Food Facts returns a 5xx other than 501, serves an HTML error page with a 2xx or 5xx status, or is unreachable — surfaced per barcode in failed[]. `upstream_timeout`: Open Food Facts did not answer within the request deadline — surfaced per barcode in failed[]. `upstream_rejected`: Open Food Facts answers 4xx or 501 Not Implemented for a barcode — surfaced per barcode in failed[]. `rate_limited`: This server's own per-minute request budget is spent, or Open Food Facts answers 429 — surfaced per barcode in failed[]. Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `upstream_error`: Open Food Facts returns a 5xx other than 501 or 504, serves an HTML error page with a 2xx or 5xx status, or is unreachable for a barcode — reported in that barcode's failed entry rather than failing the call. `upstream_timeout`: Open Food Facts did not answer a barcode within the request deadline, or answered 408, 425, or 504 — reported in that barcode's failed entry rather than failing the call. `upstream_rejected`: Open Food Facts refuses a barcode with a 4xx other than 404, 408, 425, or 429, or with 501 Not Implemented — reported in that barcode's failed entry rather than failing the call. `rate_limited`: This server's own per-minute product budget is spent, or Open Food Facts answers 429 — reported in that barcode's failed entry rather than failing the call. Other values are possible when a failure originates below the handler."

Changed5 schema fields changedSep 23, 2026

changedInput schema / properties / barcodes / items / description

Previous value: -"EAN-13 or UPC barcode (8–14 digits)."New value: +"Product barcode, digits only: 4–40 digits after any leading zeros."

changedInput schema / properties / barcodes / items / pattern

Previous value: -"^\\d{8,14}$"New value: +"^0*[1-9]\\d{3,39}$"

changedOutput schema / properties / failed / items / properties / barcode / description

Previous value: -"EAN-13 or UPC barcode whose fetch failed."New value: +"Barcode whose fetch failed, as provided in input."

changedOutput schema / properties / not_found / items / description

Previous value: -"EAN-13 or UPC barcode with no contributor record."New value: +"Barcode with no contributor record, as provided in input."

changedOutput schema / properties / products / items / properties / barcode / description

Previous value: -"EAN-13 or UPC barcode (same as provided input)."New value: +"Barcode, echoed exactly as provided in input."

Changed3 schema fields changedSep 22, 2026

changedOutput schema / properties / error / properties / data / properties / reason / description

Previous value: -"Machine-readable failure mode. Declared by this tool: `upstream_error`: Open Food Facts returns 5xx, serves an HTML error page, or is unreachable — surfaced per barcode in failed[] `upstream_timeout`: Open Food Facts did not answer within the request deadline — surfaced per barcode in failed[] `upstream_rejected`: Open Food Facts answers 4xx for a barcode — surfaced per barcode in failed[] `rate_limited`: This server's own per-minute request budget is spent, or Open Food Facts answers 429 — surfaced per barcode in failed[] Other values are possible when a failure originates below the handler."New value: +"Machine-readable failure mode. Declared by this tool: `upstream_error`: Open Food Facts returns a 5xx other than 501, serves an HTML error page with a 2xx or 5xx status, or is unreachable — surfaced per barcode in failed[]. `upstream_timeout`: Open Food Facts did not answer within the request deadline — surfaced per barcode in failed[]. `upstream_rejected`: Open Food Facts answers 4xx or 501 Not Implemented for a barcode — surfaced per barcode in failed[]. `rate_limited`: This server's own per-minute request budget is spent, or Open Food Facts answers 429 — surfaced per barcode in failed[]. Other values are possible when a failure originates below the handler."

changedOutput schema / properties / products / items / properties / ecoscore_grade / description

Previous value: -"Green-Score/Eco-Score (a–e or \"unknown\"). Often absent."New value: +"Green-Score (formerly Eco-Score) environmental impact grade: \"a-plus\" (lowest impact), then \"a\" through \"f\"; \"unknown\" when the data it needs is missing, or \"not-applicable\" for product categories the score does not cover. Often absent."

changedOutput schema / properties / products / items / properties / nutriscore_grade / description

Previous value: -"Nutri-Score letter (a–e). Absent when not computed."New value: +"Nutri-Score grade: \"a\" through \"e\", \"unknown\" when the nutrition data entered is not enough to compute it, or \"not-applicable\" for product categories the score does not cover. Absent when Open Food Facts sent none."

Changed6 schema fields changedAug 25, 2026

changedInput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

addedInput schema / additionalProperties
```
Added value: +false
```

changedOutput schema / $schema

Previous value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"

addedOutput schema / anyOf

Added value: +[
+  {
+    "not": {
+      "required": [
+        "error"
+      ]
+    },
+    "required": [
+      "products",
+      "succeeded",
+      "not_found"
+    ]
+  },
+  {
+    "required": [
+      "error"
+    ]
+  }
+]

addedOutput schema / properties / error

Added value: +{
+  "additionalProperties": {},
+  "description": "Present when the call failed. Absent on success.",
+  "properties": {
+    "code": {
+      "description": "JSON-RPC error code for this failure.",
+      "maximum": 9007199254740991,
+      "minimum": -9007199254740991,
+      "type": "integer"
+    },
+    "data": {
+      "additionalProperties": {},
+      "properties": {
+        "reason": {
+          "description": "Machine-readable failure mode. Declared by this tool: `upstream_error`: Open Food Facts returns 5xx, serves an HTML error page, or is unreachable — surfaced per barcode in failed[] `upstream_timeout`: Open Food Facts did not answer within the request deadline — surfaced per barcode in failed[] `upstream_rejected`: Open Food Facts answers 4xx for a barcode — surfaced per barcode in failed[] `rate_limited`: This server's own per-minute request budget is spent, or Open Food Facts answers 429 — surfaced per barcode in failed[] Other values are possible when a failure originates below the handler.",
+          "examples": [
+            "upstream_error",
+            "upstream_timeout",
+            "upstream_rejected",
+            "rate_limited"
+          ],
+          "type": "string"
+        },
+        "recovery": {
+          "additionalProperties": {},
+          "description": "Actionable next step for the caller.",
+          "properties": {
+            "hint": {
+              "type": "string"
+            }
+          },
+          "required": [
+            "hint"
+          ],
+          "type": "object"
+        },
+        "retryable": {
+          "description": "Whether retrying may succeed.",
+          "type": "boolean"
+        }
+      },
+      "type": "object"
+    },
+    "message": {
+      "description": "Human-readable description of what went wrong.",
+      "type": "string"
+    }
+  },
+  "required": [
+    "code",
+    "message"
+  ],
+  "type": "object"
+}

removedOutput schema / required

Removed value: -[
-  "products",
-  "succeeded",
-  "not_found"
-]

Changed3 schema fields changedJul 26, 2026

addedOutput schema / properties / failed

Added value: +{
+  "description": "Barcodes whose fetch failed, with the per-barcode reason. Absent when every fetch completed. A barcode listed here is unknown, not absent from Open Food Facts — retry it with off_get_product before concluding anything about the product.",
+  "items": {
+    "additionalProperties": false,
+    "description": "A single barcode whose fetch failed.",
+    "properties": {
+      "barcode": {
+        "description": "EAN-13 or UPC barcode whose fetch failed.",
+        "type": "string"
+      },
+      "error": {
+        "description": "What went wrong for this barcode and what to do about it.",
+        "type": "string"
+      },
+      "reason": {
+        "description": "Declared failure reason — one of upstream_error, upstream_timeout, upstream_rejected, rate_limited.",
+        "type": "string"
+      }
+    },
+    "required": [
+      "barcode",
+      "reason",
+      "error"
+    ],
+    "type": "object"
+  },
+  "type": "array"
+}

changedOutput schema / properties / not_found / description

Previous value: -"Barcodes with no contributor record. Not an error — the product may exist but not yet entered in Open Food Facts."New value: +"Barcodes Open Food Facts answered for, confirming no contributor record exists. Not an error — the product may exist but not yet be entered. Never used for a fetch that failed."

changedOutput schema / properties / products / description

Previous value: -"Comparison rows, one per barcode in input order."New value: +"Comparison rows in input order — one per barcode whose fetch completed, whether or not a record exists. Barcodes whose fetch failed have no row here; they appear in failed."

Changed1 schema field changedJul 5, 2026

changedInput schema / properties / barcodes / description

Previous value: -"2–10 barcodes to compare. All products are fetched in parallel. Example: [\"3017620422003\", \"7622210100146\"]."New value: +"2–10 barcodes to compare, returned as one row each in input order. Example: [\"3017620422003\", \"7622210100146\"]."

First observedMay 31, 2026

TDQS

Score is being calculated.

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