System entities are pre-built entities provided by Dialogflow in order to facilitate handling the most popular common concepts. Here are examples of common system entities, distinguished by their structure:
System mapping entity
@sys.datematches common date references such as "January 1, 2015" or “The first of January of 2015” and returns a reference value in ISO-8601 format:
System enum type entity
@sys.colormatches most popular colors and returns the matched color as it is without mapping it to any reference value. For example, shades of red, such as “scarlet” or “crimson”, won't be mapped to “red” and will return their original values “scarlet” and “crimson”.
System composite entity
@sys.unit-currencyis meant for matching amounts of money with indication of currency name, e.g., “50 euros” or “twenty dollars and five cents”. It returns an object type value consisting of two attribute-value pairs:
Here is the full list of system entities with examples by language: