Alexa Discovery Objects

The Alexa.Discovery interface describes messages used to identify the endpoints associated with the user's device account. You send a Discover.Response event so that a user can discover the devices and scenes associated with your Smart Home skill. For details, see Alexa.Discovery.

The following are the objects that you send to Alexa in your discovery messages.

The endpoint object

The endpoint object represents a connected device or component associated with a user's device cloud account. An endpoint describes one of the following:

  • A physical device
  • A virtual device
  • A group or cluster of devices, such as in a scene
  • A software component, such as a mobile app

Endpoint object example

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{
  "endpointId": "<unique ID of the endpoint>",
  "manufacturerName": "Sample Manufacturer",
  "description": "Smart Light by Sample Manufacturer",
  "friendlyName": "Living Room Light",
  "displayCategories": ["LIGHT"],
  "additionalAttributes":  {},
  "capabilities": [],
  "connections": [],
  "relationships": {},
  "cookie": {
    "extraDetail1": "information used by your skill",
    "extraDetail2": "you can have multiple entries",
    "extraDetail3": "don't save device state here"
  }
}

Endpoint object schema

Field Description Type Required
endpointId The identifier for the endpoint. The identifier must be unique across all devices for the skill. The identifier must be consistent for all discovery requests for the same device. An identifier can contain letters or numbers, spaces, and the following special characters: _ - = # ; : ? @ &. The identifier can't exceed 256 characters. String Yes
manufacturerName The name of the manufacturer of the device. This value can contain up to 128 characters. String Yes
description The description of the device. The description should contain the manufacturer name or how the device connects. For example, "Smart Lock by Sample Manufacturer" or "Wi-Fi Thermostat connected by SmartHub". This value can contain up to 128 characters. String Yes
friendlyName The name used by the user to identify the device. This value can contain up to 128 characters, and shouldn't contain special characters or punctuation. This field is required for all interfaces, with some exceptions. Check the documentation for your interface to see if this field is optional. String Yes
displayCategories In the Alexa app, the category that your device is displayed in. An array of strings from display categories. Yes
additionalAttributes Additional information about the endpoint. Amazon recommends that you include this field, because it can improve the user experience in the Alexa app. An additionalAttributes object. No
capabilities The capability interfaces that your skill supports for the endpoint, such as Alexa.BrightnessController or Alexa.PowerController. The capabilities field is subject to size limits. An array of capability objects. Yes
connections Information about the methods that the device uses to connect to the internet and smart home hubs. An array of connection objects. No
relationships The endpoints that an endpoint is connected to. For example, a computer endpoint might be connected to a home network endpoint. A relationships object. No
cookie Information about the device that your skill uses. The contents of this property can't exceed 5000 bytes. The API doesn't read or use this data. A list of name/value pairs. No

The additionalAttributes object

The additionalAttributes object contains additional information about an endpoint. Alexa can use this information to identify devices when different skills describe the same device in different ways.

For example, when different skills describe the same device in different ways, the same device appears multiple times in the Alexa app, which confuses users. Alexa can use the additionalAttributes object to identify duplicate devices and improve the user experience in the Alexa app.

Additional attributes object example

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{
  "additionalAttributes":  {
    "manufacturer" : "Sample Manufacturer",
    "model" : "Sample Model",
    "serialNumber": "<the serial number of the device>",
    "firmwareVersion" : "<the firmware version of the device>",
    "softwareVersion": "<the software version of the device>",
    "customIdentifier": "<your custom identifier for the device>"
  }
}

Additional attributes object schema

Field Description Type Required
manufacturer The name of the manufacturer of the device. This value can contain up to 256 alphanumeric characters, and can contain punctuation. String No
model The name of the model of the device. This value can contain up to 256 alphanumeric characters, and can contain punctuation. String No
serialNumber The serial number of the device. This value can contain up to 256 alphanumeric characters, and can contain punctuation. String No
firmwareVersion The firmware version of the device. This value can contain up to 256 alphanumeric characters, and can contain punctuation. String No
softwareVersion The software version of the device. This value can contain up to 256 alphanumeric characters, and can contain punctuation. String No
customIdentifier Your custom identifier for the device. This identifier should be globally unique in your systems across different user accounts. This value can contain up to 256 alphanumeric characters, and can contain punctuation. String No

The capability object

A capability object represents an interface that your skill supports. For example, your skill might support turning on a light by supporting the Alexa.PowerController interface. To find available interfaces for smart home devices, see List of Alexa Interfaces.

Capability object example

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{
    "type": "AlexaInterface",
    "interface": "Alexa.PercentageController",
    "instance": "<Controller instance name>",
    "version": "3",
    "properties": {
        "supported": [
            {
                "name": "percentage"
            }
        ],
        "proactivelyReported": true,
        "retrievable": true
    },
    "capabilityResources": {},
    "configuration": {},
    "semantics": {},
    "verificationsRequired": []
}

Capability object schema

Field Description Type Required
type The type of capability. Currently, the only available type is AlexaInterface. String Yes
interface The name of the capability interface. String Yes
instance You can implement multiple instances of some interfaces. In that case, you give each instance of the interface a unique name. For details, see Generic Controller Interfaces. String No
version The version of the interface. Different interfaces have different versions from each other. Always check the documentation for an interface to verify the current version. String Yes
properties The properties of the interface that your skill supports. A properties object. No
capabilityResources You can provide friendly names that users can use to interact with some interfaces. For details, see Friendly Name Resources and Assets and the documentation for each interface. Object No
configuration Some interfaces require a configuration object that contains information about how you are using the interface. For details, see the documentation for each interface. Object No
semantics You can optionally map the words open, close, raise, and lower to existing directives, for some interfaces. A semantics object. No
verificationsRequired You can optionally require the user to verify an action before Alexa performs it, for some interfaces and locales. An array of verificationsRequired objects. No

The properties object

Properties object example

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{
  "supported": [
    {
      "name": "percentage"
    }
  ],
  "proactivelyReported": true,
  "retrievable": true
}

Properties object schema

Field Description Type Required
supported The properties of the interface that your skill supports. Array No
proactivelyReported True if your skill sends change reports when the properties change. The default is false. Boolean No
retrievable True if you respond to state report requests and report the values of the properties. The default is false. Boolean No

The semantics object

When you use an Alexa interface, the voice interaction model is already built for you. Users can interact with your device by saying standard utterances. You can optionally enable additional utterances by using semantics. When you use semantics, you manually map the phrases "open", "close", "raise", and "lower" to directives.

Semantics object example

The following is an example of a semantics object in the discover response for a device that implements the RangeController interface. For details about each field, see the semantics object schema table following the example.

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{
  "semantics": {
    "actionMappings": [
      {
        "@type": "ActionsToDirective",
        "actions": ["Alexa.Actions.Close", "Alexa.Actions.Lower"],
        "directive": {
          "name": "SetRangeValue",
          "payload": {
            "rangeValue": 0
          }
        }
      },
      {
        "@type": "ActionsToDirective",
        "actions": ["Alexa.Actions.Open", "Alexa.Actions.Raise"],
        "directive": {
          "name": "SetRangeValue",
          "payload": {
            "rangeValue": 100
          }
        }
      }
    ],
    "stateMappings": [
      {
        "@type": "StatesToValue",
        "states": ["Alexa.States.Closed"],
        "value": 0
      },
      {
        "@type": "StatesToRange",
        "states": ["Alexa.States.Open"],
        "range": {
          "minimumValue": 1,
          "maximumValue": 100
        }
      }  
    ]
  }
}

Semantics object schema

Field Description Type Required
actionMappings An array of mappings between action phrases and interface directives. An array of action mapping objects. One of actionMappings or stateMappings is required.
stateMappings An array of mappings between Alexa states and your controller states. Include state mappings so that users can query the device state using the phrases Open and Closed. An array of state mapping objects. One of actionMappings or stateMappings is required.

The action mapping object

Action mapping object example

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{
  "@type": "ActionsToDirective",
  "actions": ["Alexa.Actions.Close", "Alexa.Actions.Lower"],
  "directive": {
    "name": "SetRangeValue",
    "payload": {
      "rangeValue": 0
    }
  }
}

Action mapping schema

Field Description Type Required
@type The type of action mapping. Currently, the only valid value is ActionsToDirective. String Yes
actions An array of actions that are mapped to a single directive. Valid values are Alexa.Actions.Open, Alexa.Actions.Close, Alexa.Actions.Raise, and Alexa.Actions.Lower. Array Yes
directive The directive to call for the actions. Object Yes
directive.name The name of the directive. The directive must be a directive of the interface in the capability object that the semantics object is included in. String Yes
directive.payload The payload appropriate for the directive. Some directives do not require a payload, and the type of the payload depends on the directive. For details, see the documentation for each interface. Object No

The state mapping object

State mapping object example

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{
  "@type": "StatesToRange",
  "states": ["Alexa.States.Open"],
  "range": {
    "minimumValue": 1,
    "maximumValue": 100
  }
}

State mapping schema

Field Description Type Required
@type The type of state mapping; one of: StatesToValue or StatesToRange. String Yes
states An array of Alexa states that are mapped to your controller values. Valid values are Alexa.States.Open and Alexa.States.Closed. Array Yes
value The value of your controller that corresponds to the specified Alexa states. Value Yes when @type is StatesToValue
range The range of values of your controller that corresponds to the specified Alexa states. Object Yes when @type is StatesToRange

The verificationsRequired object

When a user asks your skill to perform an action, such as turning on a light, you can require the user to verify the action before Alexa performs it. To require user verification, specify which directives you require verification for in your Discover.Response.

User verification is supported for the following interfaces only: PowerController and ThermostatController.

Verifications required object example

The following is an example of a verifications required object in the discover response for an Alexa skill that implements the ThermostatController interface and requires user verification before Alexa sets the target temperature for the thermostat. For a full example, see example for a thermostat that requires user verification.

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{
  "directive": "SetTargetTemperature",
  "methods": [
    {
      "@type": "Confirmation"
    }
  ]
}

Verifications required object schema

Field Description Type Required
directive The name of the directive to require verification for. The directive must be a directive of the interface in the capability object that the verificationsRequired object is included in. String Yes
methods The methods for obtaining user verification. Currently the only supported verification method is Confirmation. Array Yes

The connections property

The connections property represents the methods that a device uses to connect to the internet and smart home hubs. The connections property contains an array of connection objects.

Connections property example

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{
  "connections": [
    {
      "type": "TCP_IP",
      "macAddress": "00:11:22:AA:BB:33:44:55"
    },
    {
      "type": "ZIGBEE",
      "macAddress": "00:11:22:33:44:55"
    },
    {
      "type": "ZWAVE",
      "homeId": "<0x00000000>",
      "nodeId": "<0x00>"
    },
    {
      "type": "UNKNOWN",
      "value": "00:11:22:33:44:55"
    }
  ]
}

Connection object schema

Field Description Type Required
type The type of connection; one of TCP_IP, ZIGBEE, ZWAVE, or UNKNOWN. String Yes
macAddress The unique identifier for the network interface controller (NIC). Optionally include this field when the connection type is TCP_IP or ZIGBEE. String No
homeId The Home ID for a Z-Wave network that the endpoint connects to. The format is 0x00000000 with UTF-8 characters. Optionally include this field when the connection type is ZWAVE. String No
nodeId The Node ID for the endpoint in a Z-Wave network that the endpoint connects to. The format is 0x00 with UTF-8 characters. Optionally include this field when the connection type is ZWAVE. String No
value The connection information for a connection when you can't identify the type of the connection more specifically. The information that you provide in this field should be stable and specific. This value can contain up to 256 alphanumeric characters, and can contain punctuation. String Yes when type = UNKNOWN

The relationships object

A relationships object lists the endpoints that an endpoint is connected to. For example, a computer endpoint might be connected to a home network endpoint, or a headlight might be connected to a car.

Relationships object example for networking devices

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{
    "relationships": {
        "isConnectedBy": {
            "endpointId": "<unique ID of the home network endpoint>"
        }
    }
}

Relationships object example for connected vehicle endpoints

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{
    "relationships": {
        "Alexa.Automotive.IsPartOf": {
            "endpointId": "vehicle-1"
        }
    }
}

Relationships object schema

Field Description Type Required
isConnectedBy The endpoint ID of the network that this endpoint is connected to. The specified endpoint should implement Alexa.Networking.HomeNetworkController. For details, see Understand Networking and Wi-Fi Skills. Object Yes
Alexa.Automotive.IsPartOf The endpoint ID of the vehicle that this endpoint is connected to. Use this to connect parts of a vehicle, such as lights or locks, to the vehicle. For details, see Connected Vehicle Skills for Alexa. Object No
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