compare_productsSide-by-side comparison of 2 to 5 products by SKU: price ex/inc VAT, stock, brand, shipping weight and the specification bullet points, so an agent can recommend between options.
| Name | Required | Description | Default |
|---|---|---|---|
| skus | Yes | ||
| locale | No | Storefront locale such as en-GB (default), en-US, de, fr-FR, es-ES, it-IT, nl-NL, pl. Controls product names, slugs and prices. |
| Name | Required | Description | Default |
|---|---|---|---|
| comparison | Yes |
Changes observed during successful MCP inspections.
Output schema / properties / comparison / items / oneOfPrevious value: -[
- {
- "additionalProperties": false,
- "properties": {
- "found": {
- "const": false,
- "type": "boolean"
- },
- "sku": {
- "type": "string"
- }
- },
- "required": [
- "sku",
- "found"
- ],
- "type": "object"
- },
- {
- "additionalProperties": false,
- "properties": {
- "brand": {
- "type": [
- "string",
- "null"
- ]
- },
- "express_eligible": {
- "type": [
- "boolean",
- "null"
- ]
- },
- "found": {
- "const": true,
- "type": "boolean"
- },
- "in_stock": {
- "type": "boolean"
- },
- "name": {
- "type": "string"
- },
- "price": {
- "anyOf": [
- {
- "additionalProperties": false,
- "properties": {
- "bulk_prices": {
- "description": "Lower unit prices from min_quantity up.",
- "items": {
- "additionalProperties": false,
- "properties": {
- "ex_vat": {
- "type": "number"
- },
- "inc_vat": {
- "type": "number"
- },
- "min_quantity": {
- "type": "number"
- }
- },
- "required": [
- "min_quantity",
- "ex_vat",
- "inc_vat"
- ],
- "type": "object"
- },
- "type": "array"
- },
- "currency": {
- "type": "string"
- },
- "ex_vat": {
- "type": "number"
- },
- "inc_vat": {
- "type": "number"
- },
- "on_sale": {
- "type": "boolean"
- },
- "vat_rate": {
- "description": "VAT rate in percent (20 = 20%). null when unknown: ex_vat then equals inc_vat.",
- "type": [
- "number",
- "null"
- ]
- },
- "was_ex_vat": {
- "type": "number"
- },
- "was_inc_vat": {
- "description": "Price before the sale; only when on_sale.",
- "type": "number"
- }
- },
- "required": [
- "currency",
- "ex_vat",
- "inc_vat",
- "on_sale",
- "vat_rate"
- ],
- "type": "object"
- },
- {
- "type": "null"
- }
- ]
- },
- "sku": {
- "type": "string"
- },
- "specifications": {
- "items": {
- "type": "string"
- },
- "type": "array"
- },
- "stock_level": {
- "type": "number"
- },
- "summary": {
- "type": [
- "string",
- "null"
- ]
- },
- "url": {
- "type": [
- "string",
- "null"
- ]
- },
- "weight_kg": {
- "type": [
- "number",
- "null"
- ]
- }
- },
- "required": [
- "sku",
- "found",
- "name",
- "brand",
- "url",
- "price",
- "in_stock",
- "stock_level",
- "weight_kg",
- "express_eligible",
- "specifications",
- "summary"
- ],
- "type": "object"
- }
-]New value: +[
+ {
+ "additionalProperties": false,
+ "properties": {
+ "found": {
+ "const": false,
+ "type": "boolean"
+ },
+ "sku": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "sku",
+ "found"
+ ],
+ "type": "object"
+ },
+ {
+ "additionalProperties": false,
+ "properties": {
+ "brand": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "express_eligible": {
+ "type": [
+ "boolean",
+ "null"
+ ]
+ },
+ "found": {
+ "const": true,
+ "type": "boolean"
+ },
+ "in_stock": {
+ "type": "boolean"
+ },
+ "name": {
+ "type": "string"
+ },
+ "price": {
+ "anyOf": [
+ {
+ "additionalProperties": false,
+ "properties": {
+ "bulk_prices": {
+ "description": "Lower unit prices from min_quantity up.",
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "ex_vat": {
+ "type": "number"
+ },
+ "inc_vat": {
+ "type": "number"
+ },
+ "min_quantity": {
+ "type": "number"
+ }
+ },
+ "required": [
+ "min_quantity",
+ "ex_vat",
+ "inc_vat"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "currency": {
+ "type": "string"
+ },
+ "ex_vat": {
+ "type": "number"
+ },
+ "inc_vat": {
+ "type": "number"
+ },
+ "on_sale": {
+ "type": "boolean"
+ },
+ "vat_rate": {
+ "description": "VAT rate in percent (20 = 20%). null when unknown: ex_vat then equals inc_vat.",
+ "type": [
+ "number",
+ "null"
+ ]
+ },
+ "was_ex_vat": {
+ "type": "number"
+ },
+ "was_inc_vat": {
+ "description": "Price before the sale; only when on_sale.",
+ "type": "number"
+ }
+ },
+ "required": [
+ "currency",
+ "ex_vat",
+ "inc_vat",
+ "on_sale",
+ "vat_rate"
+ ],
+ "type": "object"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ },
+ "sku": {
+ "type": "string"
+ },
+ "specifications": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "stock_level": {
+ "type": "number"
+ },
+ "summary": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "url": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "weight_kg": {
+ "description": "Shipping weight in kg (packed), not net weight.",
+ "type": [
+ "number",
+ "null"
+ ]
+ }
+ },
+ "required": [
+ "sku",
+ "found",
+ "name",
+ "brand",
+ "url",
+ "price",
+ "in_stock",
+ "stock_level",
+ "weight_kg",
+ "express_eligible",
+ "specifications",
+ "summary"
+ ],
+ "type": "object"
+ }
+]Output schema / properties / comparison / items / oneOfPrevious value: -[
- {
- "additionalProperties": false,
- "properties": {
- "found": {
- "const": false,
- "type": "boolean"
- },
- "sku": {
- "type": "string"
- }
- },
- "required": [
- "sku",
- "found"
- ],
- "type": "object"
- },
- {
- "additionalProperties": false,
- "properties": {
- "brand": {
- "anyOf": [
- {
- "type": "string"
- },
- {
- "type": "null"
- }
- ]
- },
- "express_eligible": {
- "anyOf": [
- {
- "type": "boolean"
- },
- {
- "type": "null"
- }
- ]
- },
- "found": {
- "const": true,
- "type": "boolean"
- },
- "in_stock": {
- "type": "boolean"
- },
- "name": {
- "type": "string"
- },
- "price": {
- "anyOf": [
- {
- "additionalProperties": false,
- "properties": {
- "bulk_prices": {
- "description": "Lower unit prices from min_quantity up.",
- "items": {
- "additionalProperties": false,
- "properties": {
- "ex_vat": {
- "type": "number"
- },
- "inc_vat": {
- "type": "number"
- },
- "min_quantity": {
- "type": "number"
- }
- },
- "required": [
- "min_quantity",
- "ex_vat",
- "inc_vat"
- ],
- "type": "object"
- },
- "type": "array"
- },
- "currency": {
- "type": "string"
- },
- "ex_vat": {
- "type": "number"
- },
- "inc_vat": {
- "type": "number"
- },
- "on_sale": {
- "type": "boolean"
- },
- "vat_rate": {
- "anyOf": [
- {
- "type": "number"
- },
- {
- "type": "null"
- }
- ],
- "description": "VAT rate in percent (20 = 20%). null when unknown: ex_vat then equals inc_vat."
- },
- "was_ex_vat": {
- "type": "number"
- },
- "was_inc_vat": {
- "description": "Price before the sale; only when on_sale.",
- "type": "number"
- }
- },
- "required": [
- "currency",
- "ex_vat",
- "inc_vat",
- "on_sale",
- "vat_rate"
- ],
- "type": "object"
- },
- {
- "type": "null"
- }
- ]
- },
- "sku": {
- "type": "string"
- },
- "specifications": {
- "items": {
- "type": "string"
- },
- "type": "array"
- },
- "stock_level": {
- "type": "number"
- },
- "summary": {
- "anyOf": [
- {
- "type": "string"
- },
- {
- "type": "null"
- }
- ]
- },
- "url": {
- "anyOf": [
- {
- "type": "string"
- },
- {
- "type": "null"
- }
- ]
- },
- "weight_kg": {
- "anyOf": [
- {
- "type": "number"
- },
- {
- "type": "null"
- }
- ]
- }
- },
- "required": [
- "sku",
- "found",
- "name",
- "brand",
- "url",
- "price",
- "in_stock",
- "stock_level",
- "weight_kg",
- "express_eligible",
- "specifications",
- "summary"
- ],
- "type": "object"
- }
-]New value: +[
+ {
+ "additionalProperties": false,
+ "properties": {
+ "found": {
+ "const": false,
+ "type": "boolean"
+ },
+ "sku": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "sku",
+ "found"
+ ],
+ "type": "object"
+ },
+ {
+ "additionalProperties": false,
+ "properties": {
+ "brand": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "express_eligible": {
+ "type": [
+ "boolean",
+ "null"
+ ]
+ },
+ "found": {
+ "const": true,
+ "type": "boolean"
+ },
+ "in_stock": {
+ "type": "boolean"
+ },
+ "name": {
+ "type": "string"
+ },
+ "price": {
+ "anyOf": [
+ {
+ "additionalProperties": false,
+ "properties": {
+ "bulk_prices": {
+ "description": "Lower unit prices from min_quantity up.",
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "ex_vat": {
+ "type": "number"
+ },
+ "inc_vat": {
+ "type": "number"
+ },
+ "min_quantity": {
+ "type": "number"
+ }
+ },
+ "required": [
+ "min_quantity",
+ "ex_vat",
+ "inc_vat"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "currency": {
+ "type": "string"
+ },
+ "ex_vat": {
+ "type": "number"
+ },
+ "inc_vat": {
+ "type": "number"
+ },
+ "on_sale": {
+ "type": "boolean"
+ },
+ "vat_rate": {
+ "description": "VAT rate in percent (20 = 20%). null when unknown: ex_vat then equals inc_vat.",
+ "type": [
+ "number",
+ "null"
+ ]
+ },
+ "was_ex_vat": {
+ "type": "number"
+ },
+ "was_inc_vat": {
+ "description": "Price before the sale; only when on_sale.",
+ "type": "number"
+ }
+ },
+ "required": [
+ "currency",
+ "ex_vat",
+ "inc_vat",
+ "on_sale",
+ "vat_rate"
+ ],
+ "type": "object"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ },
+ "sku": {
+ "type": "string"
+ },
+ "specifications": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "stock_level": {
+ "type": "number"
+ },
+ "summary": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "url": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "weight_kg": {
+ "type": [
+ "number",
+ "null"
+ ]
+ }
+ },
+ "required": [
+ "sku",
+ "found",
+ "name",
+ "brand",
+ "url",
+ "price",
+ "in_stock",
+ "stock_level",
+ "weight_kg",
+ "express_eligible",
+ "specifications",
+ "summary"
+ ],
+ "type": "object"
+ }
+]Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": false,
+ "properties": {
+ "comparison": {
+ "items": {
+ "oneOf": [
+ {
+ "additionalProperties": false,
+ "properties": {
+ "found": {
+ "const": false,
+ "type": "boolean"
+ },
+ "sku": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "sku",
+ "found"
+ ],
+ "type": "object"
+ },
+ {
+ "additionalProperties": false,
+ "properties": {
+ "brand": {
+ "anyOf": [
+ {
+ "type": "string"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ },
+ "express_eligible": {
+ "anyOf": [
+ {
+ "type": "boolean"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ },
+ "found": {
+ "const": true,
+ "type": "boolean"
+ },
+ "in_stock": {
+ "type": "boolean"
+ },
+ "name": {
+ "type": "string"
+ },
+ "price": {
+ "anyOf": [
+ {
+ "additionalProperties": false,
+ "properties": {
+ "bulk_prices": {
+ "description": "Lower unit prices from min_quantity up.",
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "ex_vat": {
+ "type": "number"
+ },
+ "inc_vat": {
+ "type": "number"
+ },
+ "min_quantity": {
+ "type": "number"
+ }
+ },
+ "required": [
+ "min_quantity",
+ "ex_vat",
+ "inc_vat"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "currency": {
+ "type": "string"
+ },
+ "ex_vat": {
+ "type": "number"
+ },
+ "inc_vat": {
+ "type": "number"
+ },
+ "on_sale": {
+ "type": "boolean"
+ },
+ "vat_rate": {
+ "anyOf": [
+ {
+ "type": "number"
+ },
+ {
+ "type": "null"
+ }
+ ],
+ "description": "VAT rate in percent (20 = 20%). null when unknown: ex_vat then equals inc_vat."
+ },
+ "was_ex_vat": {
+ "type": "number"
+ },
+ "was_inc_vat": {
+ "description": "Price before the sale; only when on_sale.",
+ "type": "number"
+ }
+ },
+ "required": [
+ "currency",
+ "ex_vat",
+ "inc_vat",
+ "on_sale",
+ "vat_rate"
+ ],
+ "type": "object"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ },
+ "sku": {
+ "type": "string"
+ },
+ "specifications": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "stock_level": {
+ "type": "number"
+ },
+ "summary": {
+ "anyOf": [
+ {
+ "type": "string"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ },
+ "url": {
+ "anyOf": [
+ {
+ "type": "string"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ },
+ "weight_kg": {
+ "anyOf": [
+ {
+ "type": "number"
+ },
+ {
+ "type": "null"
+ }
+ ]
+ }
+ },
+ "required": [
+ "sku",
+ "found",
+ "name",
+ "brand",
+ "url",
+ "price",
+ "in_stock",
+ "stock_level",
+ "weight_kg",
+ "express_eligible",
+ "specifications",
+ "summary"
+ ],
+ "type": "object"
+ }
+ ]
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "comparison"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered; the description adds that the output is a comparison bundle spanning price ex/inc VAT, stock, brand, weight and spec bullets. It does not disclose any failure behavior (what happens if a SKU is unknown or out of range) or rate/locale caveats.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single dense sentence with the scope constraint front-loaded and the outcome framing at the end. No filler and nothing repeated verbatim from structured fields beyond the count range.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With an output schema and read-only annotations, the description need only convey scope and intent, which it does. The one gap is that locale's effect on which currency the ex/inc VAT prices are reported in is not hinted at, though it is documented in the schema.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 50% and both parameters carry their own descriptions; the description's '2 to 5 products by SKU' merely restates the schema's minItems/maxItems and item description. It says nothing about locale, whose effect on currency and naming is left entirely to the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Names a specific verb and resource ('Side-by-side comparison of 2 to 5 products by SKU') and enumerates the compared fields, so an agent knows exactly what comes back. It is clearly distinct from single-item siblings like get_product and from list/search siblings.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The clause 'so an agent can recommend between options' tells the agent the situation that selects this tool (decision support between candidates). It stops short of naming alternatives such as get_product for a single SKU or search_products for discovery.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.