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Dialogflow provides many system entities
to extract common types from end-user expressions.
For example, the @sys.color type can be used
to extract values like "red" or "blue".
You can see the full list of system entities in the
System entity reference.
For most applications, the values provided by system entities work well.
However, your application may need to add additional values for system entities.
For example, you may want to add "blue-green" to the list of values for @sys.color.
Some system entities can be extended for this purpose.
The
System entity reference
lists the system entities that can be extended.
The remaining sections of this document describe how to extend system entities.
When building an agent,
it is most common to use the
Dialogflow ES console (visit documentation, open console).
The instructions below focus on using the console.
To access system entity data for your agent:
If you are building an agent using the API instead of the console, see the
EntityTypes reference.
The API field names are similar to the console field names.
The instructions below highlight any important differences between the console and the API.
Extend a system entity from the entities page
From the entities page,
you can view system entities used by your agent
and extend them by following these steps:
The system entities currently used by your agent are listed.
Entities shown in a grey font color are not extendable,
and entities shown in a normal font color are extendable.
You can select an extendable entity and update the extended values.
Provide entity entries using the values you want to extend the entity with.
Extend a system entity with the API
If you are using the API to extend system entities,
create system entity extensions similar to how you create
custom entities.
Provide the name of the system entity you wish to extend,
and provide the values you want to extend it with.
If you attempt to extend a system entity that is not extendable,
you will receive an error.
Extend a system entity while annotating a training phrase
From the intent page's training phrase section,
you can extend a system entity while
annotating a training phrase.
If you manually annotate a training phrase part
with an extendable system entity that does not include the selected value,
you will be prompted to add this value to the system entity.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-07 UTC."],[[["\u003cp\u003eDialogflow uses system entities to identify common types in user input, such as colors.\u003c/p\u003e\n"],["\u003cp\u003eWhile system entities work well for most applications, some can be extended to include additional values specific to your needs.\u003c/p\u003e\n"],["\u003cp\u003eSystem entity support can vary by language, and some system entities cannot be extended.\u003c/p\u003e\n"],["\u003cp\u003eSystem entities can be extended through the Dialogflow ES console's Entities page by selecting the System tab and updating the values of an extendable entity.\u003c/p\u003e\n"],["\u003cp\u003eSystem entities can also be extended by annotating a training phrase with a new value or creating a new system entity through the API.\u003c/p\u003e\n"]]],[],null,["# System entities\n\nDialogflow provides many *system entities*\nto extract common types from end-user expressions.\nFor example, the `@sys.color` type can be used\nto extract values like \"red\" or \"blue\".\nYou can see the full list of system entities in the\n[System entity reference](/dialogflow/docs/reference/system-entities).\n\nFor most applications, the values provided by system entities work well.\nHowever, your application may need to add additional values for system entities.\nFor example, you may want to add \"blue-green\" to the list of values for `@sys.color`.\nSome system entities can be extended for this purpose.\nThe\n[System entity reference](/dialogflow/docs/reference/system-entities)\nlists the system entities that can be extended.\nThe remaining sections of this document describe how to extend system entities.\n\nSystem entity support differs for each language.\nSee the\n[system entity limitations](/dialogflow/es/docs/reference/system-entities#limits)\nfor details.\n\nWhere to find this data\n-----------------------\n\nWhen building an agent,\nit is most common to use the\nDialogflow ES console ([visit documentation](/dialogflow/docs/console), [open console](https://dialogflow.cloud.google.com)).\nThe instructions below focus on using the console.\nTo access system entity data for your agent:\n\n1. Go to the [Dialogflow ES console](https://dialogflow.cloud.google.com).\n2. Select an agent.\n3. Select **Entities** in the left sidebar menu.\n4. Select the **System** tab for system entities.\n\nIf you are building an agent using the API instead of the console, see the\n[EntityTypes reference](/dialogflow/docs/reference/common-types#entitytypes).\nThe API field names are similar to the console field names.\nThe instructions below highlight any important differences between the console and the API.\n\nExtend a system entity from the entities page\n---------------------------------------------\n\nFrom the entities page,\nyou can view system entities used by your agent\nand extend them by following these steps:\n\n1. Use the system entity in one of your [parameters](/dialogflow/docs/intents-actions-parameters).\n2. Select **Entities** in the left sidebar menu.\n3. Select the **System** tab for system entities.\n4. The system entities currently used by your agent are listed. Entities shown in a grey font color are not extendable, and entities shown in a normal font color are extendable.\n5. You can select an extendable entity and update the extended values.\n6. Provide entity entries using the values you want to extend the entity with.\n\nExtend a system entity with the API\n-----------------------------------\n\nIf you are using the API to extend system entities,\ncreate system entity extensions similar to how you create\n[custom entities](/dialogflow/docs/entities-custom).\nProvide the name of the system entity you wish to extend,\nand provide the values you want to extend it with.\nIf you attempt to extend a system entity that is not extendable,\nyou will receive an error.\n\nExtend a system entity while annotating a training phrase\n---------------------------------------------------------\n\nFrom the intent page's training phrase section,\nyou can extend a system entity while\n[annotating a training phrase](/dialogflow/docs/intents-training-phrases#annotation).\nIf you manually annotate a training phrase part\nwith an extendable system entity that does not include the selected value,\nyou will be prompted to add this value to the system entity."]]