# `inventory.facets` **Info: A2A invocation** This skill is invoked through A2A's `SendMessage` operation (`SendMessage` JSON-RPC method or `POST /message:send` over HTTP+JSON), not a dedicated REST URL. The same payload travels on either A2A binding — see [JSON-RPC binding](https://autoagentprotocol.org/docs/v0.2/bindings/json-rpc.md) or [REST binding](https://autoagentprotocol.org/docs/v0.2/bindings/rest.md). AAP only defines what goes inside `Message.parts[].data`. The `inventory.facets` skill returns aggregated facet counts and ranges over a dealer's inventory. A buyer agent uses it to discover what a dealer actually carries before composing a search — for example, to learn the set of available makes and models, the year range, or the price ceiling. | Property | Value | |---|---| | Skill id | `inventory.facets` | | Request type | `inventory.facets.request` | | Response type | `inventory.facets.response` | | Anonymous allowed | yes | | Consent required | no | | ADF compatible | no | ## Request shape ```json { "type": "inventory.facets.request", "filters": { "...": "(same shape as inventory.search filters; all optional)" } } ``` | Field | Type | Required | Description | |---|---|---|---| | `type` | const | yes | `inventory.facets.request`. | | `filters` | object | no | Optional scoping filters. Same shape as the [`inventory.search`](https://autoagentprotocol.org/docs/v0.2/skills/inventory-search.md) filter block; all fields are optional. | When `filters` is absent, facets are aggregated over the dealer's entire inventory. When it is present, facets are aggregated over only the matching subset (e.g. all `condition: ["used"]` listings). ## Response shape ```json { "type": "inventory.facets.response", "data": { "makes": [{ "value": "string", "count": 0 }], "models": [{ "value": "string", "count": 0 }], "trims": [{ "value": "string", "count": 0 }], "years": [{ "value": 0, "count": 0 }], "conditions": [{ "value": "string", "count": 0 }], "transmissions": [{ "value": "string", "count": 0 }], "fuels": [{ "value": "string", "count": 0 }], "drivelines": [{ "value": "string", "count": 0 }], "bodies": [{ "value": "string", "count": 0 }], "exterior_colors": [{ "value": "string", "count": 0 }], "interior_colors": [{ "value": "string", "count": 0 }], "rooftops": [{ "value": "string", "count": 0 }], "statuses": [{ "value": "available | intransit | pending", "count": 0 }], "price_range": { "min": 0, "max": 0 }, "mileage_range": { "min": 0, "max": 0 }, "year_range": { "min": 0, "max": 0 } } } ``` Each facet array entry is `{ value, count }` where `value` is the facet term (string or integer) and `count` is the number of matching listings. The `statuses` facet's `value` is drawn from the controlled vehicle status enum — `available`, `intransit`, or `pending` — since those are the only statuses that appear in inventory feeds. The three `*_range` fields are `{ min, max }` integer ranges (`price_range` in whole US dollars). `price_range` aggregates the FTC-final `price` field (see [Pricing and FTC compliance](https://autoagentprotocol.org/docs/v0.2/pricing-and-ftc.md)). ## Scoped facets example Used-only facets: ### Request ```json { "type": "inventory.facets.request", "filters": { "condition": ["used"] } } ``` ### Response ```json { "type": "inventory.facets.response", "data": { "makes": [ { "value": "Honda", "count": 12 }, { "value": "Toyota", "count": 27 } ], "models": [ { "value": "Civic", "count": 5 }, { "value": "Accord", "count": 4 }, { "value": "Camry", "count": 9 }, { "value": "Corolla", "count": 8 } ], "conditions": [ { "value": "used", "count": 39 } ], "statuses": [ { "value": "available", "count": 34 }, { "value": "intransit", "count": 3 }, { "value": "pending", "count": 2 } ], "year_range": { "min": 2015, "max": 2024 }, "price_range": { "min": 9990, "max": 38990 }, "mileage_range": { "min": 8400, "max": 142000 } } } ``` ## When to use it - The buyer agent wants to enumerate the dealer's makes/models before constructing a search. - The buyer agent needs to surface a price slider or year filter to the user. - The buyer agent wants a count of the dealer's used inventory before recommending a deeper conversation. `inventory.facets` is anonymous and consent-free. The dealer agent SHOULD return the same set of facet keys regardless of filter, omitting only those for which it has no inventory.