# Using slots?

**URL:** <https://forum.rasa.com/t/using-slots/20524>\
**Category:** Rasa Open Source\
**Created:** [October 28, 2019, 12:35am UTC](https://forum.rasa.com/t/using-slots/20524 "2019-10-28T00:35:07Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![sten](https://avatars.discourse-cdn.com/v4/letter/s/73ab20/32.png) [@sten](https://forum.rasa.com/u/sten)\
**Post date:** [October 28, 2019, 12:35am UTC](https://forum.rasa.com/t/using-slots/20524/1 "2019-10-28T00:35:07Z")

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if I have entities like this :

`* substring of a [string](type)`

but nothing is declared in domain.yaml is the slot used ?

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**Author:** ![IgNoRaNt23](https://dub1.discourse-cdn.com/flex013/user_avatar/forum.rasa.com/ignorant23/32/8029_2.png) [@IgNoRaNt23](https://forum.rasa.com/u/IgNoRaNt23)\
**Post date:** [October 28, 2019, 5:26am UTC](https://forum.rasa.com/t/using-slots/20524/2 "2019-10-28T05:26:12Z")

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What problem are you trying to solve?

If you dont specify a slot it cant be filled, so I dont see where this question is aiming at.

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**Author:** ![sten](https://avatars.discourse-cdn.com/v4/letter/s/73ab20/32.png) [@sten](https://forum.rasa.com/u/sten)\
**Post date:** [October 28, 2019, 5:28am UTC](https://forum.rasa.com/t/using-slots/20524/3 "2019-10-28T05:28:40Z")

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I’m unsure how it works ? Does it autovivify implicitly if I just use it OR I have to explicitly have to declare it in domain.yaml so I can use it in stories.md

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**Author:** ![IgNoRaNt23](https://dub1.discourse-cdn.com/flex013/user_avatar/forum.rasa.com/ignorant23/32/8029_2.png) [@IgNoRaNt23](https://forum.rasa.com/u/IgNoRaNt23)\
**Post date:** [October 28, 2019, 6:13am UTC](https://forum.rasa.com/t/using-slots/20524/4 "2019-10-28T06:13:44Z")

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This should answer your questions

> **[Domain](https://rasa.com/docs/rasa/domain/#slots)**

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**Author:** ![sten](https://avatars.discourse-cdn.com/v4/letter/s/73ab20/32.png) [@sten](https://forum.rasa.com/u/sten)\
**Post date:** [October 28, 2019, 1:41pm UTC](https://forum.rasa.com/t/using-slots/20524/5 "2019-10-28T13:41:14Z")

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that’s the problem the documentation does not explain that !!